Great project. Thank you for sharing !

very sweet amp - great work, sir. I am gearing up to build a 300B classic amp and this is a great resource for me.

Very much enjoyed the video, thanks for including the shots of SE Amp Cad, Tube Cad and PSU Designer, I use these as well, great tools. Really like the use of the EL-34 driving the 300B.

Ultra informative video, thank you! Wish i was smart enough to design a tube amp.

Great job. Thanks for sharing your design and build process.

Holy crap, just whipped those out, did ya? Really impressive. Thanks for sharing.

Magnificent. You are an artist as well as an engineer. I wish I possessed your capability. Truly fantastic. Best I've seen. Cheers from a neighbor to your south.

@ampwerx.canada

Жыл бұрын

Thanks for your comment and for your kind words.

Wow! Well done sir.

Amazing! I have a pair of DIY 300B amplifiers too.

Absolutely Beautiful, obviously an incredible amount of time and detail went into these amps. I would love to get a copy of the final design and layouts to try and duplicate.

@ampwerx.canada

4 жыл бұрын

Thank you. Send me an email by going to my web site at ampwerks.ca/ and clicking the Contact Us link at the bottom of the page.

BEAUTIFUL

You do beautiful work and I am impressed at the harmonic profile at 1 watt. I expected to see a much higher 2nd order harmonic and a descending profile of all the harmonics much like a triangular wave. I have been building push pull amplifiers for a long time and really like the Williamson design but lately I have decided to do some SE amplifier work. I have a bunch of 300B's and started searching for others that have used this tube and found your video. I really enjoyed your video and am a Klipsch owner also with the Klipschorns and other less efficient speaker systems. I also prefer the 6SN7 to the 6SL7 as I do not need that gain from the Aux level devices of today. One of the reasons I am writing to you is the way the suppressor grid is connected to the plate of the EL34 and the screen is grounded (at lease for signal). I realize the EL34 is a pentode and has three wire grids and is not the beam-power tube format of the 6L6 family but from my experience grounding the screen usually shuts the tube off. Is your schematic accurate or should the connections of the suppressor grid and screen be reversed? Not doubting the performance of your amplifier but just wondering if that is a drawing error. At the moment, the amplifier I am building will use a choke for the plate load separated by a capacitor and utilizing the full primary of a good quality push pull transformer as the matching inductor to the speaker. Modeling it in LTSpice seems to turn out OK but we know models are not always the real world. Anyway, I am very impressed with the quality of your work and the results you showed. I think I will be experimenting with a variable NFB control. I made one poor attempt at a SE amplifier years ago using a 833A and a push pull output transformer and even though the OPT would deliver over 1KW of power in push pull, it saturated at 150 mA which was the quiescent current of the 833A. I am going to do it a little different this time... :-) I experienced poor LF response, as would be expected with a saturated core, but I am confident it will turn out better this time. Any thoughts or comments you have are always welcome. Stay safe...

@ampwerx.canada

4 жыл бұрын

Thank you for your comment and for your kind words. You are right, the pin connections to the EL34 in the schematic are incorrect (although the pin numbers appear to be correct). My mistake. You are the first one to point it out. I like your meticulous approach and look forward to following your progress.

@ElPasoTubeAmps

4 жыл бұрын

@@ampwerx.canada I definitely understand. Back around 1983 I had an article published in the US and and then the UK on peak reading RF wattmeters using LEDs. I drew the output of the detector straight to ground.... fortunately, it was brought to my attention by a local ham radio operator and I was able to send a message to the UK publisher of the mistake and he corrected it. It is so easy to overlook the smallest of details. I think I have already mentioned that it is your amplifier and video that convinced me to make the commitment to build a pair of monoblocs SET's with the 300B. I have recently ordered six inductors (two 40H, 100mA chokes, two 5K to 8 ohm non-gaped SE OPT and two standard gaped core 5K to 8 ohm SE OPT, investing $250 in just those parts. ) I plan on loading the plate into the 40H chokes and isolating it from the OPT with a capacitor and using the non-gaped OPT to match to the speaker load. Looks pretty good in LTSpice models. The issue is the LF response as I see it. The two standard SE OPT are to have around just-in-case. I am also open to suggestions and thoughts so I don't have to reinvent the wheel if you see I am going too far astray. Thanks for your reply.

@ampwerx.canada

4 жыл бұрын

@@ElPasoTubeAmps Wow, that RF wattmeter error was a close call! Glad to hear that my amp project inspired you to take the 300B to the next level. Your choke plate loading configuration looks very interesting. I will be watching your progress with interest. Thanks.

Nice

Thank you, very informative. Shame about that couch :)

I see from your circuit you are using AC for your 300b filaments. is that the centre tap connected to ground via a 1k resistor? Do you have any noticeable hum? i have 300bs fed from a 6v transformer into bridge rectifier then into a lt1085 regulator circuit adjustable via a trim pot. It’s reasonably quiet but not silent as it should be. After a few minutes it’s somewhat silent. I’ve never tried AC on the filaments though. btw, looks and sounds great. love the cymbals splashing and the sound of the snare even with the limitations of YT.

@ampwerx.canada

4 жыл бұрын

Yes, the 1K resistor connects the 300B filament winding to ground and provides cathode bias voltage. The filaments are AC because I did not want to use any solid state devices in the design. Like you have found, there is some audible hum on startup, but it disappears when the tubes warm up. Thanks for your comment.

about 300b in OTL

Nice job. Wish I had your expertise. My only question is, I noticed the speaker terminals were far away from the output transformers, wouldn't it be better if it were right beside it?

@ampwerx.canada

Жыл бұрын

It would, but my priority was to minimize the length of the high impedance input leads inside the chassis since they are the most sensitive part of the circuit. The speaker leads are low impedance and are not likely to pick up hum of interference. Speaker leads are usually many feet in length, so adding a few inches inside the chassis should not impair performance. Thank you for your comment.

@sonusancti

Жыл бұрын

@@ampwerx.canada Thank you for the education. Keep up the great work!

Excellent! May I ask what the first demo piece you played was?

@ampwerx.canada

2 жыл бұрын

The first demo piece is from the KZread audio library and is titled 'This is a jazz space.' The artist is listed as Midnight North. The sound quality of the demos is really bad because it seems the mics on the handycam I used were designed to record speech, not music.

How much per pair? If possible would like to buy a pair if not too expensive!

This is beautiful work. This AA34 is beautiful! Do you plan on ever selling any of these? I've always wanted a pair of Tube monoblocks, but have never had the 2 or 3 grand they usually cost.

@ampwerx.canada

5 жыл бұрын

Thank you for your kind words. The amps are part of my main audio system right now, but I do plan to continue building new designs in the future as time permits, so I may consider selling them then to finance new projects. John

@JessHull

5 жыл бұрын

@@ampwerx.canada well I you ever do decide to sell them. Please let me know thank you .

@ampwerx.canada

5 жыл бұрын

Will do. Thanks. John

Dommage que c'est pas en Français. Sinon top!

Very nice project - if you were Japanese and the monos were green you could sell them for 20 grand (Shindo lab) ;-) May I ask a question? Please don't take it in any way offensive it is really something I would like to understand. Why tubes? I understand the SE aspect, I understand that nobody needs 50 watts, that's all fine, but good tubes are not available anymore. The last good old GEs and Telefunken and what ever you name it were sold in the 80s-90s where ppl already paid like 1200$ for one 300B and like 400 for a 2A3. The new cheap China tube are pretty much crap and after 6 month of use they start to sound really terrible even with driver tubes like ecc82 ecc83 which should last forever. Why have you not thought about building a true SE transistor amp and I am not talking Nelson Pass style but with a real output transformer. If you say "coz I want tubes" that's fair enough but if there is a technical reason I would be more than interested. And please don't take it in any way offensive, I am German and that's just the way we ask questions. I totally love your project.

@ampwerx.canada

5 жыл бұрын

Thank you for your kind words. I have been building and restoring tube and solid state amplifiers on and off for many years, but I had never designed a high fidelity SET amplifier from scratch, so that's why I chose to build these amps. This is a hobby for me and I enjoy the experience. I learned electronics in the vacuum tube era and I'm very comfortable working with tubes. I like to experiment, and tubes are very tolerant of overloads, transients, and wiring mistakes. They are pretty hard to kill. But I enjoy working with silicon too and have great-sounding amps of both types. The ElectroHarmonix 300Bs now have more than 100 hours on them and they still sound very good. Thank you for your comment. Have a happy New Year. John

Definitely musical…but not hearing any bottom end bass or punch really, hmmm. IDK.

@ampwerx.canada

2 жыл бұрын

This was recorded using the video camera's built-in mic which really is optimized for speech, not for music. Thanks for your comment.

Absurd location for the speakers, too close, one playing into a sofa ....

sound very "empty"

@dougg1075

4 жыл бұрын

roslitz you got that from KZread! Amazing

Sory bad sound

What you claim about amplification is opinion only.