I absolutely love my STR-DB930 which is very similar to this amp. Sounds incredible.

Those were beautiful amplifiers. We used to repair them occasionally, while working on the Sony repair contract. The digital board is for the digital sound processing, which is responsible for for sending the correct sound to the correct channel. The amplification for the subwoofer is done in the sub (active subwoofer), which was an active unit, with 250 Watts and an 8" driver IIRC. These units still work well today, but only on the optical in as there's no HDMI support on board, although that can be done externally. If you are getting pops or clicks, then check for dry joints on the power supply. ;)

@JulianIlett

4 жыл бұрын

And I just found the reverb section - a whole load of room types from Jazz Club to Church Hall - also done on the digital board I'm guessing :)

@johnnodge4327

4 жыл бұрын

@@JulianIlett Yes. All the preset sound effects/delays, reverberation are processed by the DSP on all 5 channels separately. It's a good system, which is still functional and useful today, as long as the optical in is used.

One of the best Amps made, I've got 2 of them, they have a nasty habit of getting dry solder joints especially on the power section and need a soldering iron run over the power sections now and then. You'll know when it needs doing as it will throw fault codes on the front panel. You'll find my repair pictures on one of the AV forums as its still there to my knowledge. They have a lovely beefy PSU unlike the nasty switch mode junk you get in some amps. There is no sub woofer amp, its just a woofer line out. The AC out is switched with the power switch. The relays also suffer from poor solder joints. Lastly the pre amp board on the top can get rather warm. I fitted a small fan inside the case to keep things cool. In its day it was a high grade amp and I think it can still hold its own today :-)

@davidarthur852

4 жыл бұрын

Ah, mine is causing huge issues and simply worn't work now. Which joints need reflowing please?

@melkiorwiseman5234

4 жыл бұрын

@@davidarthur852 Just look for the thickest PCB tracks which the transformer outputs connect to. Those are the most likely ones to need the solder reflowed. Just think of every place which is likely to get hot. They'll be another likely candidate for needing a reflow of the solder. Edit: You can't go wrong with resoldering all the major power connections on that power board which is on the left in the video. It may not help, but if you know how to solder properly then you're not likely to do any harm.

@PhoneVidoes

4 жыл бұрын

@@davidarthur852 have a look on the bad caps forum as this was where I put some pics up on this thread www.badcaps.net/forum/showthread.php?t=6648 there is also the relays which can end up needing some reflowing. Lots of the PCB work can be done just by taking the bottom panel off which means you dont need to do any major stripping. Also I would go along and resolder all the large power transitor connections which mount on the heat sink, Again I think these can be got at from the underside. Its about a 15min job with a soldering iron. this cured all my "protector faults" and stopped it suddenly shutting down and making horrible noises.

@jeannoelsandrazie1874

Жыл бұрын

I have a STRDE845, which is still in use. The main problem is, as you say, the dry solder faults. I use an electrical panel fan on top of the receiver. It may not be pretty, but it keep the receiver cool as spares may be drying out now. Cheers

Ive still got my STR-DB940, was a great amp in its time. There was a problem with some of the amps where there was dry solder joints on the surround relays which caused the relay to switch on and off intermittently. Fresh bit of solder sorted that 👍. I now use an Onkyo TX-RZ 820.

Nice piece of amplifier! I have the STR-DB790 and a friend of mine has the one you have. They differ but both of them are very good sounding amps.

@dantdmnl

3 жыл бұрын

It's nice indeed, we have one in our living room with a 5.1 setup and it sounds quite nice. I have a Sony STR-D565 in my room with 2 JBL LX500's and it's pretty damn good too.

Sony receivers are notorious for having terrible soldering, it mainly cracks at the relay, so if it doesn't have sound and doesn't click, just re solder the driving transistor and the relay and you should be good

@hermannschaefer4777

4 жыл бұрын

Most amps have this problem after some years. They often use 90 degrees vertical cards and other stupid mechanical connections, which, together with the heat and cooling, kill all solder connections. If an older amp has problems, first check the caps, then all solder connections, then the relays...

We've gone downhill, now we've got DIY Dave in his shed taking apart his appliances. Please go back inside and play electronics again.

Julian introduces his stubble cam at 4:37 !

There's a Service Manual of this STR-DB940 including schematics here: sportsbil.com/sony/STR/STR-D/STR-DB840_DB940.pdf The schematics of the power amplifiers are on page 33, no MOSFETs, just complementary common collector output stage using Darlington NPN, PNP. A common circuit that many amplifiers use. Looks like there are only 5 power amps. There are 7 outputs because the main L + R have two outputs A and B. These just share the same power amp. The relay clicking is due to the speaker output protection, it waits (and measures) that the outputs are stable enough and have almost no DC voltage on them. Only then is it safe enough to connect the speakers so the relays click.

Added excitement ....inspect it with the power on!

Looking very similar to the faulty Sony STR-DB835 I tore apart for spare parts a while back. If I recall correctly, those big power transistory things were Darlingtons. I had intended on repurposing the transformer and caps for a nice and beefy linear benchtop power supply. Never got around to building it, let alone actually design the thing. I've got notes somewhere on the pinouts of the transformer and DC board, although it wasn't that difficult to figure out, so I could pick up the project again once my plate is a little clearer. Yes, the volume control on the remote drives the volume knob motor. Which is bizarre considering it's all digital, so they could just tell the microcontroller to increment or decrement the volume independent of the input from the volume rotary encoder, rather than telling the motor to rotate the encoder. I'm guessing they just did it to give the volume knob that nice heavily damped feel. As for the volume getting quieter when you increased the treble frequency, that's most likely a combination of the frequency response of the little tweeters and the filters on the tuner. Analogue FM radio has a fairly low bandwidth, so the low-pass filter in the tuner output stage would roll-off relatively low compared to any filtering on the other inputs.

This thing is quite literally a gold mine of nichicon caps. It still hurts my heart that I don't have it anymore

@neddyladdy

4 жыл бұрын

Do you mot know the meaning of literally ?

@nldestinyx1440

4 жыл бұрын

@@neddyladdy what does that matter? 😂

@westinthewest

4 жыл бұрын

@@neddyladdy I don't think s/he meant 'literally' literally.

The workbench surface appears to be made from decking material in the new studio. Useful material, I replaced the top of an old garden table with decking planks a couple of years ago 👍

Take a look at the Sony Service Manual (86 pages). Sony make some of THE best support documents for service engineers. They include schematics, PCB layout designations, block diagrams of the chip internals, chip pin designations, self test modes, factory reset, etc. Not quite as good as earlier manuals which had theory of operation, but still, pretty darn good. sportsbil.com/sony/STR/STR-D/STR-DB840_DB940.pdf

@mrpsychodeliasmith

2 жыл бұрын

Thanks for the service manual link. I have just been gifted on eof these but there is an issue with the sound.

I have (and still regularly use) the standard two-channel stereo amp from Sony's QS range (TA-FB940R). I think it's around twenty years old, by now. The matching DVD player from their range at the time would've been something like the DVP-NS900V.

I have a Sony DVD player from the mid 90's that has the same colour and styling as that amp... I have been looking for some components that match it so thanks for this :D

Cool. I've got the STR-DB930. Interesting to compare them :)

@vince_martyn

4 жыл бұрын

I have the STR-DB925 which is sitting in my study because it played up, I replaced it with a newer amp and can't remember what was wrong with it now.

What a gorgeous amplifier. :)

I used to use a Yamaha A595 for surround which is similar is age and specs than this Sony. It wasn't very good. Thankfully I gave up on surround as it's very gimmicky and bought a much better Cambridge Audio stereo amp. I was amazed by the difference especially with the bottom end response. But you can't complain about a freebie !

7.1 surround has 3 front speakers (left, centre and right), 2 side speakers (left and right), 2 rear speakers (left and right) and a sub-woofer. 5.1 surround is almost the same except without the side speakers.

Those white things are duel emitter resistor in each power amplifier. Yes it does only have 5 power amplifiers but probably inputs for 7 down mixed, The relays you hear coming in after a few seconds are speaker protection relays usually monitoring DC off set or power issues. The reason you have a 4/8 ohm switch is because the amplifiers will overheat or even blow up if you use 4 ohms, they get round this but either changing the output stage voltage or adding limiters to reduce power output. I would NOT use 4 ohm speakers at all on such equipment. Power output is usually rated with just 2 channels working, all 5 on at once will really drop the voltage and power will really drop. Which is just as well as the heat sinks are VERY under rated for sustained high power output. They rely on the fact that a 5 channel movie, most of the time only a few channels will operate at any one time. A film like Star Wars will make the amplifier get VERY hot (over hot on my opinion) A fan added will prolong the life considerably. Even the digital chips often overheat because of no heat sinks. Still, you do get alot for the money but almost every part of it (in HiFi terms) are a compromise.

@DrGreenGiant

4 жыл бұрын

What's the extra lead on a dual emitter resistor?

@MichaelBeeny

4 жыл бұрын

@@DrGreenGiant It's usually a common lead.

I love this reciever but if you like this youl loveeee the da777es, its unbelieveable how good it is.

I have the STR-DB1070, never failed me and is in use every day to this date. Only issue I can mention is that the display is getting a bit dim. Very happy with it. The one you have looks like mine but mine are 6.1, it has a center back speaker in addition to your setup that's 5,1. Never used that feature tho as it basically uses a Dolby pro logic type of processing to create the center channel audio as there are no such thing on Dolby digital or dts. Other difference i can spot is that yours are missing rgb ports on the back and my volume knob is not motorized. It's just a digital sort of arrangement, does not turn when you use the remote, but the dB level shows on the display.

For those of us that don't have solar. These are a great source for a multi tap transformer to power your bench top power supplies.

I spent some $4,000 dollars in Sony Audio gear back in the 80's. Wish I spent that money on Pioneer.

4:37 LD = LaserDisc, coaxial = two wires to carry the digital signal as opposed to optical

At least it's output stage is class A/B, I gave my older Sony ES pro logic amplifier to my son when I upgraded to a much newer Sony ES amplifier which had HDMI, more output power and more features only to realize that I don't like it! No direct access to hardware bass and treble controls! Class D amplifier output stage! It's definitely more powerful but it's very harsh sounding when listening to music! Movies sound just fine. The older one sounded excellent on both movie's and music! I have never had any luck with class D amplifiers, not even in the car! The only place that they seem to be perfect for is portable applications where quality doesn't matter much, you just need it to be loud since you loose a lot of volume to the atmosphere! It looks like someone has been inside that amplifier before, the transistors look like they have been replaced, I doubt that Sony would have been so sloppy with the heatsink compound! Considering it's age, I would be guessing that most if not all those Nichi Con capacitors need to be replaced! Nichi Con capacitors have a good reputation but I have found that there was a period where they didn't last as long as one would expect, my son has a Sony DAT machine that was one of the early models and it's a work of art inside, everything is copper shielded! Beautiful Nichi Con capacitors are everywhere! It's like someone decided to use the best of the best of everything! But every single one of those capacitors were bad! Non of them had leaked their electrolyte but they all leaked DC, the copper shielded transformer ran hot, after a complete re cap, it's power consumption dropped dramatically and the transformer ran much much cooler! A re cap is a job in itself but if you like the piece of equipment and want it to last, re cap it, it's worth the effort and it's cheaper than buying a new one, Yamaha is making new versions of their older stuff but they aren't cheap, they never really were, but that's the choice that we have! Re cap an older model or pay more and get a brand new one! But you have to make sure that the new one isn't junk like the majority of them out there today!

If I remember correctly from school back in the 80s, the output stage is class B push/pull with NPN and PNP. It was quite common I believe.

@matsv201

4 жыл бұрын

Some have AB stages where the push pull is slightly offset.

I still use this thing. Only downside, I have to use optical in, because it doesn’t support HDMI

Can I plug in only a passive subwoofer? and what pl;ug should?

Ive got this amp, it doesnt go in to protection mode but it has no sound on all speakers, i can faintly hear the radio but only if i crank the volume to maximum, i think the voltage amplifier ic's have been destroyed by bad solder connections. and dont touch those capacitor terminals because they will kill you.

Ive got one of these 😊 youngest son absolutely s**** himself when he turns it up 🤣🤣

@dantdmnl

3 жыл бұрын

We have one of these in our living room lol, we mainly use it for movies.

I've also own a Sony STR DB940 - nice device

Hi Mr . Julian. How are you.. I didn't found your Mppt charge controller...... what happened about that...... how to get that..

@benwinkel

4 жыл бұрын

it's called Muppet

Just realised you're in the new shed (Forgive me, I'm a bit tipsy) - is this because the missus is kicking you out of your normal "studio", or are you going to use this for bigger projects?

New drinking game, take a shot each time Julian mispronounces Nichicon. 😋

@JulianIlett

4 жыл бұрын

Nichicon - he he - now I know :)

@TomStorey96

4 жыл бұрын

@@JulianIlett :-) How do you think your new shed will hold up in winter, in terms of comfort that is? Or do you only plan to use it during the warmer months?

You should get one of the new fancy AV-amps with a calibration mic. The calibration process will blow your mind.

Unplugging kit helps with not worrying about getting a belt from it. Just a tip.

Hi i have got this one and also TEAC AG15D, so really don’t know which one is better. Just need some help Thanks

That's a 5.1 amp. It just has A and B for the main speakers

some relays are for speaker protection or output switching or other things

@JulianIlett

4 жыл бұрын

Yeah, I think the delayed click was the anti-thump relay(s). There must also be relays for the AB speaker selection.

"Sorry this is all off camera, but this is a massive thing" Is that a John Holmes quote?

Julián, i note that can be interest any review about USB Quick Charge 3.0 involved ac chargers, powerbanks (pass trught) many things benefit fast charging at 9 v and 12 v

Subwoofers usually have their own amplifier so not surprising there isn't one onboard

The fuses are probably for split supply (2 fuses) and a supply for the digital board

@JulianIlett

4 жыл бұрын

Split supply with 71v capacitors - nice :)

@sparkyprojects

4 жыл бұрын

@@JulianIlett Found a service manual on 'electrotanya' those white things next to the transistors are .22 ohm 5w dual (matched) resistors (there's 3 connections on the bottom) and connected between emitters of the pairs with middle going to ground (0V rail).. and apparently it's a 61v 0 61v supply plus a 32v supply.

The electrolytics are NichiCON, not NichiON. I think you need to install a compressor in your new shed - perfect for blowing out the cobwebs.

@JulianIlett

4 жыл бұрын

Nichicon - I noticed the 'C' while editing - couldn't see it on the camera's tiny LCD :)

Haha, great "look inside", albeit HiFi and AV stuff not your specialty yet but give it some time, very enjoyable to see your explorations, thinking NichiCon, Laserdisc, DTS and all that stuff connected to AV-receivers nowadays.

Nichicon not nichi-on

You mean a receiver?

Hello sir I have a different kind of problem I need help with I bought a underwater ROV drone "CHASING GLADIUS MINI" and my son broke the 50m tether/cord off the WiFi box so I stripped it and found a black and white wire in it surrounded by Kevlar material, that tether/cord needs to be somehow connected to a 4 prong connector, I opened up that WiFi communication box and it has red(L), black(N), yellow(BAT) and blue(GND) wires not sure how to reconnect this?

@jasonlee3247

4 жыл бұрын

Colour doesn’t matter, just connect the 4 wires in any order and it’ll be working again 👍

I used to have that exact model. It's a shame that it broke down on my otherwise I would still have it. It sounded amazing!!!

@dantdmnl

3 жыл бұрын

I still have it and it still works great! It sounds amazing with our 5.1 setup.

@nldestinyx1440

3 жыл бұрын

@@dantdmnl my neighbors where complaining with the STR-DB940 and they aren't with my new Pioneer AV receiver, that says enough 😂

@dantdmnl

3 жыл бұрын

@@nldestinyx1440 My neighbours have never complained about it and they say that they don't hear it, I kinda feel like they're lying lol, you probably understand why I think that.

@nldestinyx1440

3 жыл бұрын

@@dantdmnl HAHAHAHA yes I do, have you solved the cold solder joints on the bottom?

@dantdmnl

Жыл бұрын

@@nldestinyx1440 No I haven't

very nice think I have one somewhere

That has the obvious old Sony look to it/ Old Yamaha also all looks the same. It's like they have their preferred methods of manufacturing, parts and connectors then stick with them for quite a few years in all their products.

the white things next to the mosfets are resistors i think

@danielhorne6042

4 жыл бұрын

2 resistors in one package

@kalikatz2382

4 жыл бұрын

The white things with sticky uppy wires are resistors for calibrating the amplifier bias voltage. Should be done every so often.

Probably only generating a single David!

withe things are resistors

part 2 of project ASBO me thinks

LD is Laserdisc.

i have a onkyo tx-sr605 probs not the best but its an amp at the end of the day lol

Julian, you could speak with "Techmoan" on his channel and he will help you out with identifying all the information about this Audio Amp. Have Fun, Joe

0:47 sounds like classic FM

It's circa 2000 and 100W per channel. Maybe put the cover back on before you break it?

Probably 5.1 with 5 amplifiers and an active sub.

@danielhorne6042

4 жыл бұрын

normally the sub out is purple rca socket which aint amplified well aint on my onkyo -tx-sr605

Sony takes the time to make it sound as good as possible and Julian only uses two tweeters. 🎶 🙉😬

@JulianIlett

4 жыл бұрын

No worries - more tweeters on order ;)

@andymouse

4 жыл бұрын

@@JulianIlettHahahhaha !

As old as that thing is EXPECT the caps to Fail.

Oh do be careful with that old chap, wouldn't want to upset the neighbours now would we ?

@JulianIlett

4 жыл бұрын

My new rules: Benign music from next door - classical music or opera. Autotuned gangsta-rap (with racist lyrics) - high power 16kHz sine wave :)

Wow couldn't do it. Everything is so close and disorienting. Had to stop video while I comment so I don't lose my lunch. Bummer I like watching this guy. Now I won't until he moves to a bigger space. Sorry Julian video quality went way down hill.

@JulianIlett

4 жыл бұрын

A few tweaks needed in my new studio, then video quality will be back to normal :)

@bp420a5

4 жыл бұрын

@@JulianIlett not mad at you and still subscribed. Learned a lot from you over the years.