I remember those 50s vintage stereo cabinets. Vox AC30 clone. 6BQ5 x 4 = 30watts but the power tubes would need to be rewired in parallel to get that kind of power. Minor circuit modifications to turn it into a guitar amp, you would need a good front end guitar circuit on the phone input. Dried out filter caps, typical in these old amps.

Thank you so much Uncle Doug and Rusty! This is such a good video. I grew up in Monte Vista, Cupertino, Silicone Valley now. I went to school with Steve Jobs and Steve Wozniak. My uncles sold their orchards to Apple. But what you really awoke me to is Ampex in Sunnyvale. Anyway, I use to collect all of these tubes out of these amplifiers which now you are pointing out are so useful and should be saved. God, we would pull out all of these tubes and save them in shoe boxes and trade them with a couple of our school mates for fun. Now that I am old and have played bass all these years, I realized the my little Ampeg svp-pro with five tubes in the preamp have been discontinued. I plugged into it a few weeks ago when finding out that it was discontinued by Ampeg, and OH MY GOD! The tubes make all the difference! Thank you for your educational video. I am now going to get my eleven year old son to get interested in these. I did not know that those nice tubes could still be good. Aloha, Paul

@UncleDoug

9 жыл бұрын

Paul Mikul You're welcome, Paul. I guess we all took tube-powered devices, like amplifiers, for granted while growing up, and now wish that we had rented a storage garage some time in the 1960's and kept them all, instead of "sending them to the dump". We would now probably have a fine assortment of tubes and amps......and a $100,000 storage bill :) Thanks for posting, and please get your son involved. We need new recruits to carry the torch after we're gone.

I heard an Ampex amp once and it had an amazing sound! What a find your friend made! Too many people are so excited when they find a vintage piece of tube gear that they can't wait to plug it in without proper precautions being taken only. Thanks for sharing.

@UncleDoug

9 жыл бұрын

You're welcome, Mick. I was impressed by the Ampex also, so I ended up getting it from my garage-sale-hunting friend. You're right about the hazards of simply "firing up" (sometimes literally) new gear, particularly without using a Current Limiter (see video) to protect the circuit from damage. Much harm is done by careless "smoke testing" of vintage gear. Thanks for your input :)

Love this old gear! Love the marvelous heavy duty engineering inside it, & love the way you present it! Thank you!

@UncleDoug

2 жыл бұрын

Thanks, Neville. Glad to hear it :)

love these type of videos doug, these are what ive been looking to score on.

@UncleDoug

9 жыл бұрын

chuck jones Glad you like them, Chuck, and best of luck in your pursuit of great old electronic devices.

I use to plug up my Les Paul to my moms old stereo cabinet like that Zenith. Man the sound was awesome.

@UncleDoug

4 жыл бұрын

I'll bet it was, James. Sweet memories of our youth :)

@jameswatkins7263

4 жыл бұрын

@@UncleDoug so that would be around Midland, Tx to Van Horn area for you?

@UncleDoug

4 жыл бұрын

@@jameswatkins7263 The other way, James.....El Paso, Las Cruces.

@jameswatkins7263

4 жыл бұрын

My sister graduated from Mayfield high school in 86. I went to school on the Missle Range and then we moved to Germany. Question for you. Is a Rocky R12S amp, designed by Dennis Kager/Sundown Technology Inc(Moog) worth repairing? I can't find the schematic, but the info I have says it has a 6V6 and 2 12AX7. I have the amp chassis but need to build a cab and get a 10" speaker. Has the original transformers no tubes.

Thank you so much for your feedback,and it saves me lot of time without lot of readings searching looking for best transformer around.there are so many forums talking about different ideas about how they effective in terms of sound quality(i don't know if it's true or not) thanks again for your kindness.love all your videos..

@UncleDoug

9 жыл бұрын

Alvin s You're welcome, Alvin.

Thanks for another great video! I'm sure all of us would be interested in maybe a one or two part video in which you would demonstrate how you would go about testing a find like these.

@UncleDoug

9 жыл бұрын

You're welcome, Robert. On amps such as this, I visually inspect for shorts, missing insulation, burnt parts, obvious problems (like are the correct tubes in the sockets?) and then hook them up to a proper-impedance speaker (if they lacked one), plug them into a Current Limiter (see my video on how to make one) and Variac if they've been sitting for a while (most have), and see if they work. Based on what happened, I would make repairs; test voltages, plate current (PC), and plate dissipation; and monitor the amp for 30 minutes or so of operation, usually monitoring PC. If the CL flashed bright at any time during this entire procedure, I would immediately shut the amp down and correct the cause. I have demonstrated all of these steps at different times in different videos and the procedure is fairly simple and effective.

Thanks for the interesting video Doug. We don't see much of this kind of stuff for sale where I live north west of England. Its a real feast for your eyes and ears. Take care and see you both again soon. Colin

@UncleDoug

9 жыл бұрын

You're quite welcome, Colin. Thanks so much for watching and commenting. It's always good to hear from you :)

Thanks for another great video, Doug. Last year I purchased a Silvertone console record player with a stereo single-ended 6bq5 amp. I have the parts from other such finds to turn it into a PP, which is still between workbench and boxes. I have plans to use the nice SE transformers for Champ-style builds. I love what you do - keep it up!

@UncleDoug

9 жыл бұрын

You're quite welcome, Britt. When I get comments like this, it makes me want to run out to my workshop and start on a new project. There's nothing like having a hot soldering iron, plenty of parts, and a snoring old dog curled up nearby :) Never fear.....Rusty and I will be doing this until the undertaker says otherwise. Best of luck with your projects, Britt. It's always great to hear from you.

WOW! that is awesome. Love those vintage amps

Fantastic finds! Congrats to the fortunate buyers of these hidden jewels. Another good place to find inexpensive tube amps is in older organs, such as Hammond and Lowerey.

@UncleDoug

2 жыл бұрын

Thanks for your input, CS.

Hi. I have 2 sets of the Zenith amp and preamp at the beginning of the video. One I have overhauled and is reinstalled in it's original cabinet with Cobra-Matic turntable. Sounds really nice. The other is in the process of being overhauled and will be installed in another cabinet with another Cobra-Matic turntable. Fun to have around.

@UncleDoug

5 жыл бұрын

I'll bet they are, Bruce. It's good that you're restoring these old devices back to proper function.

I love this! I recently scored a 1958 Hoffman Electronics satellite speaker with a lovely pair of Schumacher transformers, and some Amperex tubes. All the basics needed for a stripped down, one channel AC15 style amp. This will be my first foray into converting an amp for guitar use. Exciting stuff!

@UncleDoug

Жыл бұрын

Sounds like a great project, Stephen. Best of luck with it.

This summer I grabbed a mid-60's Airline console stereo for $5. Turns out the dual class-A Ultratone amp has the perfect complement to re-work into a push-pull mono amp - plus a load of low noise radio tubes to spare.

@UncleDoug

8 жыл бұрын

+Karlfalcon A great score, Karl. Hearing success stories like this renew my interest in garage sales. Thanks for sharing :)

I as inspired by you and disassemble a old turntable amplified by valves I fixed the amp, is working now, iam trying to build it in a wood base, thx for your teaching an videos 😊

@UncleDoug

4 жыл бұрын

You're welcome, Diogo. Best of luck with your projects.

Hi Doug I was salivating over that speaker 😝 very interesting video 👍

@UncleDoug

7 жыл бұрын

Greetings, Steve. Thanks.....it was indeed a very nice speaker :)

Some really cool quality finds. Love the information. Thanks Doug.

@UncleDoug

2 жыл бұрын

Thanks for watching, Picker :)

Great video! Nothing sounds like vinyl through a stereo tube amplifier. You don't have to, but upgrading the speakers can give you even more 3D sound. I ran my 1958 Pilot stereo into a pair of Infinity 150 studio monitors for years and listening to "Mountain" or classical music is incredibly detailed. Electrolytic recap is highly recommended with power conditioning, etc. Great advice Doug!

@UncleDoug

2 жыл бұрын

Thanks for your helpful hints, Amo.

down in ecuador watching an uncledoug vid. love your show !!!!. ibecause of you i always look for cool oldy's to mod. they gotta be in ecuador somewhere. i heard once a man passed away here. and had a lil shop...... the family gave away all his tubes > that's so nice. cheers to you, uncledoug :)

@UncleDoug

7 жыл бұрын

Thanks so much, FT. Rusty sends his greetings to all his fans in Ecuador :) Good luck with your hunt for vintage amps. We hope you do better than we have lately :(

Hi Uncle Doug! I just pulled a beautiful 25 watt tube amp out of a 1946 Bell and Howell Filmosound 16 mm projector. Along with it came a very early alnico Jensen 12' speaker. The amp and speaker sound divine.

@UncleDoug

8 жыл бұрын

+Bruce Nasmith Wow....what a great discovery, Bruce. I love the pre-50 circuits and an Alnico Jensen to boot !! I shiver to think how good it must sound :))) Congratulations. This is what keeps me going to garage sales, even though 99% are wastes of time.

@brentgilbert4208

2 жыл бұрын

I THINK Anthony Wilson (GREAT jazz guitarist) uses a Bell & Howell tube amp like you describe!

OMG!!! That JBL speaker in that Ampex is a diamond! What a find!

@UncleDoug

9 жыл бұрын

Greetings, Brad. I agree....in fact I liked it so much that I ended up buying the Ampex unit from the guy who found it at an estate sale. I'm not sure what to do with it now. It's really too nice to tear apart, but not all that neat-looking or usable as is.....decisions....decisions.

@rogertyler3237

3 жыл бұрын

Yah They Do Have A Good Sound. I Have 3 JBL Bluetooth Speakers & A Ryobi Bluetooth Speaker. & They All Sound Great.

@jamiboothe

2 жыл бұрын

I use the A 692 model and pre amp it with a peavey Decade. It sounds amazing, also the 692 has a large bolt that runs into the back of the speaker and through the back of the cabinet so you can tune the speaker box for taste. Another thing that can be done is using the door to muffle the sound, to bring out crazy bass tones. Two of these used through stereo outputs can change your world.

That Ampex tape player amp is really a work of art. Very well made! Sorry I found it funny "almost burned his house down!" Some people really just don't get it. It is bad to burn out anything vintage like this.... but smoke from a resistor doesn't equal "about to burn the house down!" The uninitiated are so easily scared! Thanks again for sharing these old devices with us!

@UncleDoug

6 жыл бұрын

You're welcome, David :)

Thats the best advice Ive heard to purchase parts to build I have come buy.

@UncleDoug

8 жыл бұрын

+John Miner Thanks, John. It's sometimes possible to acquire hundreds of dollars worth of parts for a fraction of their value if you can find an old amp, phonograph, etc. that is being sold dirt cheap on Craigslist or in a garage sale.

Hell Uncle, Greetings from Ireland. Picked up a nice Pignose 700A at a car boot or garage sale last year. The seller thought it was a broken radio. he didn’t realise that they are designed to switch off when the input jack is removed! Got it for under $10. Also got one of those hi fi console chassis for $40 incl shipping on eBay. Two original RCA 6V6s and two very nice sounding G.E. 12AT7s. Rewired it as a 5D3 Tweed Deluxe the one with the self-balancing paraphase phase inverter - ideal for harmonica distortion. Enjoy your videos. Keep up the good work…

@UncleDoug

8 жыл бұрын

+Dave Keating It sounds like you've been busy, Dave. Best of luck with your discoveries and acquisitions, from your pals in Texas, USA :)

Great job, makes me wanna go look for stuff!

@UncleDoug

9 жыл бұрын

Thanks, BC. Good luck with your search. Let us know if you turn up any good stuff :)

The Zenith console is a spectacular home stereo too. Those 12” Zenith AlNiCo’s are some of the best Hi-Fi 12’s you’ll ever hear. I’d think good and hard before parting that increasingly rare beauty out.

@UncleDoug

Жыл бұрын

Thanks for your input, W.

Another great video! Thanks for sharing.

@UncleDoug

9 жыл бұрын

You're welcome, DR. Glad you liked it :)

I picked up 2 "Mono each" Lier Siegler/Bogen mo200a Valve/tube 200 watt rms amps with "8" 8417 output tubes, and these amps were...Standard in the Industry back in the Day. They have multi/ohm Z = Impedence Taps, and Just a line cord "2 Wire", a on/off toggle switch, and a main gain slotted screwdriver shafts for turning gain up & down. Still have from 1981 when I worked at a Transformer Factory, they were in boxes wrapped with suran wrap, they are Rack Mount and they look & Play like New. Class A Circuitry I'm sure. A Sweet Find "Uncle Doug !

@UncleDoug

7 жыл бұрын

Wow, an exotic find indeed, Mr. R. I can imagine what an incredible dual monobloc stereo you could create with these beasts....or a really stout pair of guitar amps. Let us know how they turn out.

Hi Uncle Doug! I'm a brazilian huge fan of yours! Your videos are just amazing! Congratulations!

@UncleDoug

7 жыл бұрын

Greetings, Wellington, and thanks for your very nice comments :)

Very interesting. I'll have to keep an eye out . Thanks for taking the time to make these videos.

@UncleDoug

9 жыл бұрын

You're welcome, Bryan. Check your newspaper for garage and estate sale listings, as well as Craigslist. Best of luck with your pursuit of vintage gear :)

@onemancarnage

9 жыл бұрын

Hope I'm not being a pain. But I've found something already. Not sure if I can do anything with it or if I even should . It's an old 60, something reel to reel . Haven't picked up yet but it has a tube amplifier . Couldn't beat the price !,free. If you don't mind I'll send you a picture of it and any specifications , tube type etc. As always we all appreciate the videos and the time you and rusty put into them.

@UncleDoug

9 жыл бұрын

Congratulations on a good find, Bryan. Some of the amps in reel-to-reel tape decks are of good quality. No need for a photo, since I am not an expert on such recorders. You need to find a model number and do a Google search for info about it and perhaps a schematic of the amp. Rusty and I are glad you enjoy the videos....thanks for watching :)

@onemancarnage

9 жыл бұрын

Yeah sometimes I get a little over the top about things. And thanks for the information. Cheers.

@UncleDoug

9 жыл бұрын

Likewise, Bryan. If you make something of the amp, please feel free to post the results on my FaceBook page: Uncle Doug's Vintage Amps. You are always welcome :)

Hi Uncle Doug, nice to see some vintage electronic rescuing going on. I visited our local Waste Management Facility (Junk Yard) or as we Aussies call them "Tips" last weekend and at their "shop" picked up a Line 6 display unit for guitar pedals which had a power supply unit with leads for about 10 x9volt power adapters. Plus an old speaker cabinet, with an Australian made ( yes like the USA we used to make things) 1970's Plessey - formally Rola /celestion factory, 8" speaker, took it home and it's loud with a nice fat bottom end. It's amazing what you can pick up for a few dollars although Tube stuff is getting rarer to find. Kind regards, Colin

@UncleDoug

9 жыл бұрын

Greetings, Colin. It's always good to hear from you, and to learn of your recent "finds" at the local junk yard. It is sad that our countries have dispensed with so much of their manufacturing capability, preferring instead to import goods from areas with a less expensive work force. Old treasures like your cabinet and items featured in my videos are about all we have left from the "good old days", which makes them all the more dear. Thanks for watching and for posting :)

I speak fluent canine. Rusty said "Drop ball? Don't joke like that."

@UncleDoug

9 жыл бұрын

dieselscience Yes, he did....and in an Australian accent, which is a nice change of pace from the neighbor's German shepherd and Scottish terrier.

@thatellipsisguy8984

4 жыл бұрын

If he was speaking real Australian, he would’ve used slightly stronger words...

I agree 6bq5's are capable of super realistic sound, low power but that is all up to what type of speaker used. great fun video uncle Doug.

@UncleDoug

8 жыл бұрын

+jeff b Thanks, Jeff :)

your'e a great teacher, thanx for your videos, ive learned a lot !

@UncleDoug

5 жыл бұрын

You're welcome, Gene. Thank you for your nice comments.

Excellent video uncle Doug!

@UncleDoug

8 жыл бұрын

+Martin Thanks, Martin.....glad you liked it :)

Nice find. I only say that the EL84'S were typically run very hot and typically very long in old hifi's and as result are typically fairly spent by the time you find them...just tap them while in operation and watch for sparks!

Hi Uncle Doug, Rusty & Jack, I hope your all doing good. Spring is just around the corner, yeah. In the video, I heard you mention that the 4 6BQ5's, etc. would be the makings for a Vox AC 30 amp. I have always wanted to see your version of one. Unless the stereo amp was a customers, it sounds like you have the makings for one, unless it was sold. It would make an awesome video series, provided your still doing them. Lately, it seems as though all my favorite channels have decided to quit YT. I understand life is precious, and, one can only do so much, Thankyou for all you shared and taught about amps. Be good, C.

@UncleDoug

7 жыл бұрын

Greetings, Cass. The stereo amp belonged to a customer and is long gone. Rusty and I haven't given up on KZread, but have been very busy with other hobbies for the past few months. Hopefully, we can get back into video production before we both croak :)

@cassvirgillo3395

7 жыл бұрын

Uncle Doug Hello Uncle Doug & Family, Glad to hear you have something other than Fender on the brain, LOL. Your a couple of lads with a long way to go. No reply necessary. Peace & Happiness from Oregon, C.

Doug, My New Year's resolution is to watch ALL your vids. ; ) I'm soaking up all kinds of good knowledge and being entertained at the same time. I don't know why KZread has a video (to the right of this one) on making beef jerky in your own oven. Maybe it's intended for Rusty...

@UncleDoug

9 жыл бұрын

Greetings, Rick. I'm very flattered by your New Year's resolution.....best of luck and be sure to have plenty of caffeine handy for the video marathon :) I guess Rusty's love of jerky is so widely known that even the advertisement placement spies at KZread have heard of it :) Thanks so much for your nice note, and be sure to have a great New Year.

Enjoyed that very much. The Ampex is quite a gem. Love the vids!

@UncleDoug

9 жыл бұрын

Thanks so much, BK. Glad you liked the amp and the videos :)

thanks uncle doug... really cool video... that speaker in that ampex is gorgeous..

@UncleDoug

7 жыл бұрын

You're welcome, YRU. I agree, it's really well designed and constructed.

I really need to get my Victor model A sound reproduction amplifier going. It's part of a Victor 16mm sound projector and it's a nice little Western Electric-designed tube amp with a 6v6 push-pull output stage.

@UncleDoug

8 жыл бұрын

It sounds like the Bell & Howell projector amp featured in a recent video series, D20. If you haven't seen it yet, please check it out.

You've inspired me to go out early and do some granny trampling.

@UncleDoug

5 жыл бұрын

Be sure you have proper certification from the state, Felton. You don't want to get cited for "undocumented trampling".

Treasure! lots of tube sockets, tubes and transformers to use.

@UncleDoug

2 жыл бұрын

Yes, indeed. A plethora of useful items !!!

Ooh I got goosebumps when you showed the Zenith. We used to have that same model when I was a kid. My Mother worked for Zenith for quite a few years. I have no idea what happened to ours. Ill have to ask her about it. Thank you.

@UncleDoug

9 жыл бұрын

Hi, Brian. I think all of us over 50 or so can recall a similar console record player somewhere in our past. At first it was wonderful and played continuously, later it became junk to be hauled off, now it's back to being wonderful. I see why some people hoard things......you never know which items will return to their former glory :)

Shhhh UD, you're going to turn people on to my parts sources! Just kidding, this is absolutely true, there are so many parts out there to work with, and cheap! One of the best things to get hold of is an old combo TV-radio console, sometimes you can find them as low as $20, or maybe even free if you haul it away. Multiple power/output transformers, miles of wire, multiple speakers, carbon resistors (check for drift), fuse holders, potentiometers, chassis, and many times vacuum tubes that still have a lot of life in them. Plus, by disassembling them, you learn a lot about how all the parts go together, so it's educational, too. And yeah, you can use old TV sweep tubes to make some serious guitar noise!

@UncleDoug

9 жыл бұрын

Excellent advice, MA. I can see we'll be bumping elbows at the next estate sale :))

Nice finds indeed. Tube console hi-fis are often asking big money. Good deal for the tube complement and those output transformers. That Ampex must have been a pricey piece in its day.

@moldyoldie7888

Жыл бұрын

Ampex products were pricey, period.

The title alone got my thumbs up !

@UncleDoug

Жыл бұрын

I hope you enjoyed it Travis :)

Doug, last weekend I found an old Lowery organ tone cabinet from 1949. It had 60 Ken-Rad 12AX7 tubes in it. The tubes were mfg. in 9/48. On the back of the tube panels were a bunch of nice Bumble Bee capicitors. 16 on each panel. Quiete a good find for $50.

@UncleDoug

9 жыл бұрын

Bbendfender Good grief, BB, a discovery like this is what we garage-sale addicts are all looking for......a lifetime supply of exceptional 12AX7's and a whole hive of bumble bees. Congratulations!!! (Even though we're all jealous :)

Awesome finds Uncle Doug! Once again great video...hey Rusty, King says WooF, he said you would understand.

@UncleDoug

9 жыл бұрын

Greetings and thanks, F86. Rusty says that while he is deeply conflicted by the existential implications of King's statement, he still prefers tennis balls to Frisbee's.

@TheF86Sabre

9 жыл бұрын

You just made my day! lol. "I'll pass on the wisdom.

About 5 years ago I would scour CL every week looking for vintage tube stuff people were selling or getting rid of (most of it was the latter). My first score was donations from a guy who lived nearby who had gotten into tube amps for a bit and then decided he was done. I got several PAs (a 20W Davis PA, a Bogen CHB35A, and a Grommes Precision Electronics 60PA) and a Hammond L100 series organ amp from him. My first organ was a Conn Caprice with a stereo amp and 45 or so 12AU7s. lol. It had a stereo amp which didn't interest me. The speaker was mediocre, so I ended up parting it out and selling the parts and made a tasty profit. $30 for the organ and I made over $150 on the amp itself. Got a Hammond L103 (which I made into a Marshall 18W style), an M3 (which I made into a 5E3-ish style). I also got a Baldwin and a Kimball and a Radio/Phonograph/wire-recorder thingie with a mint 15" JBL speaker in it) From all of it, I got some great speakers (some P12Qs, the 15" JBL), miles of wire. From the one solid state organ I parted out, I got a lifetime supply of shielded cable. Made a good bit of change parting those things out made some nice amps out of it. The only thing I regret parting out is the Grommes PE 60PA. It had a really nice replacement OT on it that I wish I had kept. Oh well, at least I traded it for a really nice OT, so it wasn't a complete loss.

@UncleDoug

2 жыл бұрын

Your story merely emphasizes the upside of shopping for electronic gear at garage sales, etc., Pete. Thanks for sharing.

Very nice videos Uncle Doug!

@UncleDoug

8 жыл бұрын

+ΜΠΑΜΠΗΣ ΡΟΥΧΛΑΣ Thanks :)

My parents' Magnavox hi-fi had two 12's and two 6V6 power tubes with sockets for two more. It was my first guitar amp after I added a quarter-inch jack. A building contractor stole it out of my storefront.

@UncleDoug

2 ай бұрын

Those building contractors can be a shifty lot ;)

that ampex was gorgeous

@UncleDoug

8 жыл бұрын

Thanks, Tom. I agree, their electronic items are all first-class :)

Great video on all topics! I'm familiar with McGohan amplifiers, both tube and solid state. I have several myself. They were always very good sounding and durable, even up to through the earlier solid state units. The last of their solid state amps got rather junky due to the imported components and "improved" designs. Try and find yourself an earlier MS-203 with the vinyl wood grained hoods. You will be impressed! They are amazingly powerful for a 20 w amp, and wonderful sounding. I know Jim McGohan through work ( Don was his dad). Sadly the company was forced to discontinue building amplifiers due to the imported equipment being far less expensive. ~Kat

@UncleDoug

7 жыл бұрын

Thanks, Kat, both for your nice comment and your very informative input.

love that ampex , great video

@UncleDoug

7 жыл бұрын

Thanks, Blair. The Ampex really is a nice unit :)

i live in Vietnam. I love your dog and like your video.

@UncleDoug

5 жыл бұрын

Thanks so much, Huu. We appreciate your time and interest.

Hi Uncle Doug....when I asked about the OT testing, I wasn't worried about DC voltage being used but only if the "wall wart," 12 volt @500ma would hold it's voltage while testing so I would get consistent results. Thanks as usual for your knowledge...Daniel

@UncleDoug

2 жыл бұрын

You can monitor the AC input and the AC output simultaneously with two DMM's, Daniel, which would make it evident if the supply was stable.

Another sublime cinematic feature Rusty. I truly enjoyed that cameo of you in the beginning, the juxtaposition of the ball in your jaws is a fine metaphor of post neo-realistic struggle. Uncle Doug, I've heard about some that disconnect that negative feedback line. What's the story there?

@UncleDoug

7 жыл бұрын

Rusty appreciates your analysis, Rick. Apparently, his years of study with Stella Adler really paid off. Disconnecting the NFB causes earlier breakup and overall raunchier tone. See my video in which I demonstrate the effects of different NFB resistance on my Homebuilt Fender Champ (scrap parts).

Tube Amplifiers with point to point soldering.

@jonsanford0

9 жыл бұрын

Hot

@UncleDoug

9 жыл бұрын

***** Then you're in good company, Karl. All of us are tube ampoholics.....hopelessly addicted to the nostalgia and tone of tube amplification.

I know this is a late posting, but you should know that all amps in the series of Ampex "portable amplifiers" are very hi-fi. The speaker is an oem by JBL... basically the D208 with additional magnetic shielding. This was incorporated because Ampex was a very high-end tape recorder company, and one could expect these amps being used in the field in locations where Ampex recorders and lots of recorded on and unused tape was present. From the Mullard design 6AF6 input to the full-range JBL, these amps, with their common cathode self-biasing topology and simple but effective (and very musical sounding) tone controls, they are genius in design and despite their diminutive size and 10 WRMS ouput are true thoroughbreds. ~If only... I had kept the four that I've had over the years. DRAT! Be sure, ASAP, to replace the coupling caps between the cathodyne phase splitter outputs and 6V6 output tubes since every one of these amps I've worked on had some degree of DC leakage which will at a minimum distort the otherwise superb sound of an Ampex Portable and anything deyond that will eat the 6V6s' lunch. BTW, did I mention that these units are keepers? Please restore and use the amp, it's just wrong to keep them around as dustcollectors. There is plenty of inferior junk better suited to that task. -DE-

@UncleDoug

7 жыл бұрын

Good advice and information is never too late, Richard. We sincerely appreciate this helpful input. You'll be glad to know that I have kept the Ampex unit completely original, other than the component changes described in the video......and the coupling caps you mentioned. It is simply too beautifully designed and constructed to alter. Thanks again :)

What a neat video. And tubes (e.g., that matched quartet of 6BQ5s) are WONDERFUL at reproducing music. Oh to be young again & over at the nearby airbase & NOT walking by the things that said McIntosh on them... thanks for sharing the great finds.

@UncleDoug

9 жыл бұрын

You're welcome, Wes. Vintage Amperex 6BQ5's can be a little pricey, and this matched set of four really got my attention....glad you liked them. I share your remorse over not buying all the Fender, Gibson, McIntosh, etc. gear that was available over the years. Perhaps this video will encourage youngsters not to make the same mistakes we did :)

@weshoward4301

9 жыл бұрын

Uncle Doug I had one question for you (maybe wrong place). I see regularly on your bench what I think is a "leak light". I'm gonna build one of these. If so, have you found an optimum bulb wattage to make modern house AC play nice with vintage transformers as are found in my BF Champ? Thanks! :) (Oh yeah, good advice before on stiff-arming the little old ladies at those yard sales - ya gotta bring it!)

@UncleDoug

9 жыл бұрын

Wes, I made a video showing how to make a Current Limiter. You need a 250W incandescent bulb for smaller amps like the Champ. If you can't find one locally, they are available on Amazon. Good luck :)

@weshoward4301

9 жыл бұрын

Uncle Doug Many thanks - I'll seek it out. :)

Parade of Bargains. Love it

@UncleDoug

8 жыл бұрын

+BUCKSKI Check your local newspaper for garage and estate sales this weekend, Buck. There may be some good items :)

@BUCKSK1

8 жыл бұрын

+Uncle Doug I will be looking at the Alemeda Swap Meet too. It's a gold mine. Except you have to push through more hipsters than grannies.

@UncleDoug

8 жыл бұрын

Hipsters can be trampled almost as easily as grannies, if they get between you and a great deal :) :)

I have a McGohan M102 similar to the one in your video. The one I have has the EZ81/6CA4 rectifier tube as opposed to the solid state that is in the video. I am sure it is a somewhat older version. We converted it to a Marshall circuit, the phono is high gain and the mic is normal. We changed the pots from left to right to Gain Treble Bass and Master Volume. Also all pre-amp tubes were changed to 12AX7. Major overhaul but worth it. This is clean or mean.

@UncleDoug

4 жыл бұрын

Wow.....that sounds like an excellent series of modifications, VR.

great inputs on cheap amp starter bait. My Eico Signal Tracer is having a bumpy road but i am learning and getting closer. to my first amp making music, I hope.

@UncleDoug

3 жыл бұрын

Thanks, Dennis. Please see my video on building a Fender Champ from an old RF signal generator.

Nice finds. Alas I've noticed recently that folks take the tubes out of these sets and sell them separately on eBay, etc. This makes restoration of the sets so much harder and the prices of many tubes has now become crazy. Oh well.

@UncleDoug

9 жыл бұрын

Yes, having to buy a whole set of tubes would definitely take the "bargain" out of the term "garage sale bargain". Ebay has ruined the simplicity and joy of hunting down treasures. Everyone is a self-professed expert....utterly determined to squeeze every dime out of every item. Pawn shops are the worst, in my opinion. They hunt down the absolute highest price ever obtained for an item that even vaguely resembles whatever they're trying to sell.....and then add 10%. Thanks for your input Z :)

You still have the Ampex? Seems like it would made a cool little powered monitor for, like, a solo acoustic performer or something.

@UncleDoug

9 жыл бұрын

You're right, I hadn't considered that use for it. Thanks for your input, Brad :)

Used to have a bunch of Electrovoice 15” speakers with cast aluminum frames like that ( huge magnets, they weighed a ton )

@UncleDoug

5 жыл бұрын

They are excellent speakers, Michael. I can't imagine how great a 2 x 15" cabinet would sound with a pair of them.

Now i need to keep some money in my pocket while i take the kids around trick or treating. I might see a treasure,and go home with some candy of my own. great video Uncle Doug.

@UncleDoug

9 жыл бұрын

Thanks so much, Franky....glad you liked it. It really pays to keep the eyes and ears open for "treasures" that other people seem to consider "junk". I'm always glad to haul it off for them :)

I call it dusty gold! Thanks for sharing!

@UncleDoug

9 жыл бұрын

You're welcome, JR.....glad you liked it :)

Re. using old wire, it may sound obvious but give the stuff a quick look to see if it's useable. Natural rubber was often used as insulation and it can perish and become brittle, as can other formulations after 5 decades of use and heat. The wire can also oxidise along it's whole length, having reacted with both the jacket and air. Otherwise it's a great idea.

@UncleDoug

7 жыл бұрын

Good advice, Martin.

C’mon, Rusty. Get it together, man. 😁 Aloha to you and family, Uncle Doug. Hope all is well. ✌️🤘🤙

@UncleDoug

2 жыл бұрын

Thanks, D ;)

Wow, I am so envy of that garage sales tradition in US! :)

@UncleDoug

9 жыл бұрын

Greetings, Nusior. About 98% of the garage sale items are uninteresting or pure junk; but, just like mining for gold, every once in a while, you can make a major discovery.

@nusior

9 жыл бұрын

Uncle Doug Too bad garage sales aren't a common thing in Poland. We have flea markets but it's inconvenient unless you're living next door to one :) But if shipping overseas wasn't so expensive to me, I'd "mining" ebay all the time.

@UncleDoug

9 жыл бұрын

I'm sure that overseas shipping must be awful. Shipping even within the U.S. has become quite costly. Ebay pressures sellers to offer free shipping, but it's becoming more and more difficult for sellers to absorb this increasing expense.

What a great video! Get up early and start trampling grannies!!! Hilarious.

@UncleDoug

7 жыл бұрын

You gotta do what you gotta do, if you want to get those Garage Sale Bargains !!!

Thanks for the education!

@UncleDoug

7 жыл бұрын

You're welcome, PM :)

Noticed that the schematic you show is for an Ampex 621, but the unit you have is a 622. They are similar, but perhaps the most interesting thing that you didn't mention is the compensating network and the switch on the external speaker jack. The compensating network is designed to match the internal speaker and enclosure to produce the flattest possible output. Since that would incorrectly color a different speaker system, the compensating circuit is switched out when an external speaker is plugged in, providing a flat output to the external speaker.

@UncleDoug

9 жыл бұрын

Ampex Quad Very interesting, AQ. Thanks for the input :)

great find sir, i once found a old made in England Sugden A88 class a amp.it was very good for what i paid.should of kept it though.

@UncleDoug

8 жыл бұрын

Yes, it would have been a good candidate for conversion to guitar use, Ralph. Don't feel too bad.....there are lots more convertible amps still out there, waiting for you :)

I know what you mean. I picked up a 1956 Victor projector speaker cab only and it had a Jensen P12Q in perfect condition. sounds even better than the 1946 speaker.

@UncleDoug

8 жыл бұрын

+Bruce Nasmith So many of these ancient and often-overlooked devices contain fabulous components, Bruce. It's like hunting for buried treasure :)

Hi uncle Doug. I've learnt quite a lot from your videos but I'm still quite baffled by a lot of it, I would like to learn more on electrical engineering and some amp building. I can't afford to go back to collage to learn properly, are there any books or sources you could recommend me reading to start learning about amps and electronics etc. keep up the great videos!

@UncleDoug

9 жыл бұрын

***** Thanks, Brian. It's a complex topic that takes time to understand. Gerald Weber has written some good books (see Amazon) and the Internet is full of instructional sites and videos. Start doing some searches on topics you don't understand. You can learn all this yourself if you take the time and apply the energy to do so. Good luck.

Loving your videos Especially the two on oscilloscope usage. What part of Texas are you in? I am near Abilene.

@UncleDoug

5 жыл бұрын

That's good to hear, Ron. I'm further west.....El Paso.

Ok thanks I think that's my best, thanks.

I was just given an old Baldwin organ. Man, what an amazing piece of work that is! I think it has over 30 12AU7s and 25 12AX7s. And two nice big 6L6s. A massive PT and a nice OT. Not to mention lots of super nice old cloth covered wiring. Gotta love Craig's list. Thanks for the video. It made me jealous!

@UncleDoug

8 жыл бұрын

+John Heaphy This sounds like a major coup, John. Twenty-five vintage 12AX7's, and they're probably a good brand, is like winning the lottery. Congratulations !!! Now I'm jealous :)

@inUR2teeth

8 жыл бұрын

hope you will have the veerrry nice idea to upload a video and let us, the very jealous people, hear that jewel of yours.. ;)

@UncleDoug

8 жыл бұрын

Which jewel, IT ?

@inUR2teeth

8 жыл бұрын

+Uncle Doug I am willing to hear his Baldwin organ.

@UncleDoug

8 жыл бұрын

Hopefully, John will read your comment and post a video. However, I'm not sure if the Baldwin is in good working condition.

Uncle Doug - They just don't make your particular model of American any more...Super informative instructional videos and great dog. Many Many Thanks...Ed M, NYC

@UncleDoug

8 жыл бұрын

Thanks so much, Ed. Rusty and I really appreciate your nice comments :)

Outstanding!

@UncleDoug

9 жыл бұрын

Thanks, Chance :)

I had two huge cabinets with vinyl players in them in my house as a kid. We didn't have a lot of money, so I suspect they were secondhand. I'm fairly sure they still worked too

@UncleDoug

2 жыл бұрын

.....and they probably would have made good guitar amps :)

I've recently picked up a Challenger HF8 -- a little mono hi-fi amp built around a pair of push-pull 6V6s. I plan to convert it to guitar use and build it into a little tweed-covered Champ-style cabinet; it'll be a fun project for my kids and I to work on. Luckily, I was able to find a Photofact sheet for it, which has been really helpful. One of the funny things about this little amp is the input... there are 3 inputs: magnetic phono, crystal phono, and tuner. The mag phono goes though what I assume is an RIAA-equalization stack and into the first half of a 6SC7 for recovery before going on to the second half of the 6SC7 for the first gain stage (the crystal phono just goes right into the second half of the 6SC7). Then to the volume and treble controls before going into the first half of a 6SL7 (the second half of the 6SL7 is the phase inverter). The bass control appears to be part of the negative feedback loop into the first half of the 6SL7. My plan is to do a basic cap job on it, then start experimenting. One thing I want to do is relocate the controls... I'm not really pleased with the controls it comes with (tapped linear pot for volume - turn it one way for phono, the other way for tuner! - and the power switch is on the bass control!). I was thinking about putting a new set of controls into a new chassis that I can locate at the top of the cabinet (I'd prefer to keep the amp chassis at the bottom for various reasons), but I'm concerned about introducing noise with such a relatively long run of wire.

@UncleDoug

9 жыл бұрын

Jason Thorpe Jason, your circuit analysis and conversion plans all make good sense. Several vintage amps I have encountered use the two-chassis approach, with pre-amp and controls at the top and power supply and output section on the floor of the cabinet. You can greatly reduce, or hopefully eliminate noise by using shielded wire for signal-carrying cable(s) between the two chassis. In fact, I often use shielded cable for signal-carrying wires within the pre-amp, just to play it safe. Good luck with your project.

Thanks for your very informative videos, I have a question for you, I purchased a 120 volts subwoofer from the USA that I am using with a stepdown transformer here in the UK, but I notice that the subwoofer manufacturers have put the power transformer for the amplifier in a separate compartment away from the amplifier, can I change the transformer for a 240 volts one?

@UncleDoug

9 жыл бұрын

You're welcome, Anthony. If the subwoofer operates on 120VAC, and the transformer you intend to install converts 240VAC down to 120VAC and can satisfy the current demands of the subwoofer, then it should work just fine. In effect you are simply replacing the external step-down transformer with an internal one, if I understand your inquiry properly.

Great video.. Regarding the Ampex amp: That 2W 1K resistor is not really a screen resistor. The screens have their own 20µf filter cap so that reistor is a typical B+ screen dropper between the plate- and screen cap instead of a more expensive choke.. Also the amp has a 40µf fiter cap after the 6AX5 rectifier.. That sounds a little overboard as the datasheet has a recommended 10µf cap, though the datasheet says you can use more capacitance but you need to increase the effective plate supply impedance or the rectifier will be damaged..

@UncleDoug

9 жыл бұрын

MrAnders1976 Thanks for your knowledgeable input, Mr. A.

One thing I noticed about that Ampex amplifier/speaker unit that again confirms how excellently designed it is: the fact that the whole amplifier circuit is on at full blast volume, and the only audio level control is right at the very input. The amp circuitry is all crammed together in a tiny space and there are no hum or white noise or regeneration-feedback, etc, problems, Uncle Doug?

@UncleDoug

8 жыл бұрын

I agree, Terry. The entire unit displays a high degree of engineering and good design. The speaker and enclosure are particularly impressive.

Beautiful examples of point to point construction. It would be worth the cost just to study how they were built, plus I could have saved a lot of money on my scratch build. Thank you and Rusty. The quiz; McGohan = cathodyne, Ampex = long tail pair.

@UncleDoug

9 жыл бұрын

Greetings, Andrew. It's always good to hear from you. To me, the beauty of point-to-point wiring is that it's all done completely by hand.....a lost art. Today, nothing I can think of is done by hand, except maybe obscene gestures :) Rusty says you get 100% on your quiz. Congratulations !!

@tubical71

9 жыл бұрын

Uncle Doug Too late for exam, damn ;)

hey uncle Doug. this stuff is amazing. great videos, thank you. could you possibly do a video showing a beginner how to make a very basic, as simple as possible, tube amp? I've kind of wanted to build myself a basic headphone tube amp, and although all the info is available out there,.. seeing it physically put together in your videos really helps. I say headphone amp, but a mini first tube amp would be cool too.. like a 1 Watt. would any of this be possible? thanks. have a great day!

@UncleDoug

7 жыл бұрын

Greetings, VC, and thanks for the nice comments. I have posted several video series showing how to scratch-build small amps, but of the 5W to 8W variety, such as the Fender Champ. The procedures are essentially the same to produce a 1W amp, so you could study the videos and simply apply them to a lower watt build. The technical and procedural challenges are essentially the same for both. Good luck.

@virtualcar2359

7 жыл бұрын

Uncle Doug thanks buddy 👍🍻 I haven't made it all the way through all your videos yet.. so I look forward to seeing those. thank you.

@UncleDoug

7 жыл бұрын

You're welcome.

that jbl speaker is awesome !

@UncleDoug

7 жыл бұрын

Thanks. It really is a nice speaker, Peta :)

Greetings Uncle Doug, first off, many thanks to you for all the great videos. I've been working on electronic gear and tube amps for 40 years and I learn something new from each of your videos. Well done. When I watched this one I was shocked and amazed to see the Ampex utility amp as I have two of them. Great little amps, I was missing the cord on one so I modified it to use a standard grounded power cord. A friend and I each bought a pair of these amps from another co-worker whose Dad was a salesman from Ampex tape machines. They used to haul the speakers around to demo Ampex 440 tape decks. I'm looking for an input selector switch if you know of a source. Say hi to Rusty for me.

@UncleDoug

8 жыл бұрын

+Archtop6038 You're welcome, Arch, glad you enjoyed the videos. Rusty says "Hi" back :)

I have greatly enjoyed your videos Uncle Doug. I look forward to your return. Today I am playing with a Stromberg Carlson Sau-10 and have only a fuzzy schematic to go by. Could you suggest where I might find one? A standard Google search found a few Sau-10's but only one very fuzzy schematic. This is a 4 tube, single ended 6L6 output equipt PA amp with a single 6au6, 6av6, 5y3 and 6L6.

@UncleDoug

7 жыл бұрын

Thanks, Dan. I'm sorry but I have no special source for schematics. Like you, I keep running searches until I come up with one that I can read......and am generally, but not always, successful. Best of luck.

And don't mention the presentation.Wonderfull.I like it.

@UncleDoug

9 жыл бұрын

Thanks so much.....glad you liked the video :)

Thanks for your prompt reply, no inside the subwoofer, there is a transformer, with four metal pins on top I think that's were the power comes in from my step down, now the question is how many volts would the secondary be feeding the amp and I would have to find out if I can re wire the primary side for 240 volts.

@UncleDoug

9 жыл бұрын

I really can't provide any sort of insight on this matter without personally inspecting and evaluating the transformer. If no literature or schematic are available, perhaps you could contact the company that made the unit and ask them. Best of luck.

Uncle Doug Can you do a video on OP Amp explanation and show schematics too....Thanks Jim

@UncleDoug

6 жыл бұрын

Greetings, Jim. I deal exclusively with vintage tube amps, so Op Amps are outside my field of interest and expertise. Hopefully, there are many videos on this subject available on YT, posted by experts in the topic.

Lucky dog. Good for you bro. It looks like art inside they should not have hidden the electronics back then.

@UncleDoug

7 жыл бұрын

Thanks, WP. Rusty sends his regards to the fine pup in your icon photo.

awesome!

With the first amp you can build a stereo amp and be able tu use stereo pedals in front, or a stereo multi fx.

@UncleDoug

6 жыл бұрын

Good suggestion, IP :)