The 1988 Technics SU-V550 amplifier arrives!

Got this at a flea market. Let's take a look inside, and then turn it on!

[@tharkthax3960]

I've got same amp. Similar problems, noisey switches and dry joints. Fixed it all up and even recapped it. It's a good amp with decent power. Enjoyed your video 🙂

[@travis4798]

It's not a cheaper design by any means, having those heat pipes. The package would get too hot with just a long heatsink so the heat pipe helps dissipate heat more evenly. I'd take a Technics over a Sony any day. ;)

[@MacPhantom]

Aah, nice score! And if you don't like it you could easily sell it for the same price again. The best matching amp for the SL-P770 would be the SU-V90D (although I don't like that one tbh). Or if you really want to go to the top, an SE-A100/SU-A200 combo would do the job as well. About Class AA: this consists of two amp stages (voltage control in class A and current drive in class B). Key principle: the current drive amp does most of the amplification, and the voltage control stage kicks in when the other amp would normally start producing crossover distortions (as all class B amps generally do). So you'd have the best of both worlds: good efficiency from class B and zero crossover distortions from class A.

[@zigzigfuck]

nowadays to find a good stereo amplifier with an extrem low distortion such the Technics SU-Vxx series ...it's not so easy ! ( even with the more expensive recent amplifiers ) the class AA amplifier is made with 4 ampliers : 2 voltage control class A + 2 current drive amps resulting in extremely low distortion + a wide dynamic range. ( it's true ! ) result is only 0,005 % to 0,002 % distortion !!!!

[@Mosfet510]

Don't feel bad about spending too much $$ at the flea market, I've done it and I bet a million others have as well. Your 'spending limit' changes when you get there fast! lol btw, I remember that amp when it came out, back in the day it was a hell of a nice amp for the price, and had a great sound to it. Hang on to it, it's a classic.

[@EastAngliaUK]

I have 2 Technics amps and surprised at how much I like them the Technics SU-610 is even pretty decent and has plenty bass if you want it.

[@rsanchez7111]

Gracias for sharing Doctor cassette

[@wayneljm]

Whats the VA rating on the back? You said 50watt transformer? These amplifiers are awesome, my experience with them is they have more stable juice than every other one besides high end Harmon kardon at the time. Those modules at the back may be a fuse, relay, resistor, even enclosed preamp for linear input leveling. I had a massive Sony stereo amplifier and separate preamp and it was amazing the power circuits that was used back then. These days a small amp using only 12v input can be very good so long as the speaker impedance draws enough from that low voltage amp.

[@uxwbill]

The design is very similar to that of the earlier SA-510 receiver, where the same heatpipe design is used with a discrete output stage. (Mine is rather broken, with a tuner MCU that crashes and a heat pipe that has no problem crossing 70°C within minutes.)

[@tbirdsteve1]

I have the SUV-660 and it's still awesome.

[@linusevosonic]

I think my Mum has the same Amplifier and it still works fine. But she bought it in beginning of the 90s i guess. I'll check out the exact Model Number when I'm at her place on christmas. She also got the CD-Player, Tuner and Tape Deck of that Series.

[@yannis92preloude]

I used to repair loads of this type of Amp. Also sold alot in the past. Great amp and Great sound.

[@StresSdidri]

Using heat-pipe technology back in 1988, i think that's quite impressive

[@Heimbasteln]

Yeah, they didnt really have that technology back then.

[@Transistor512]

I did not know that heatpipes had been around so long time in electronics. Interesting

[@sheep1ewe]

Your channel is way better then some other moreknown channels here sinse You actually show the components and the interna structure in the devices wich some of the other channels don´t , he just taking the lid of snd flashing the inside but no real wiews of the components or cirquit boards, etc wich actually is the parts i am intrested in... The external look and the function is things i can find on a regular google serach... But not a wiew of the components as You show here.

[@aljosagajst8725]

why was I sure that there is stk in there before you lifted the amplifier

[@B.Ruslan1978]

Nice amp

[@gavincurtis]

The only reason that STK module is still working is they made the heatsink big enough. Those modules do have decent sound, but always failed prematurely due to heatsinks being far too small.

[@DrCassette]

Yes, the STK modules tend to run very hot, even when there is no input signal.

[@TheTechGuyYT]

Stk and svi are very different

[@ashleycox432]

I'm a huge fan of the 80s full-size Technics amps. The SU-V7 or SU-V9 if you can find one are exceptionally good. Adjusting them is pretty tricky because of how the class AA system works, but when they're adjusted they usually stay that way.

[@DrCassette]

+Ashley Cox I'll have to see about adjusting this amp, I do have the service manual. If the procedure is as complicated as your comment makes me think then I'll stay away from it. I have re-adjusted the quiescent current on the Sony amp as that was way too high.

[@ashleycox432]

+DrCassette Well, it's not too terribly difficult. I know the V7 and V9 require a scope to adjust them, I forget what the V550 requires off the top of my head but it's probably fairly similar. Certainly nothing you'll struggle with.

[@DrCassette]

+Ashley Cox Hmm, I don't have a scope in the apartment, so that's probably not going to happen then...

[@GattoIsidoro]

Usually cooling with freon pipe

[@smugglersrun7779]

I have the SUV 6 you will like the sound l bet

[@eklektos44]

Ceramic inductors L 101 and L 102.

[@dawidczajkowski2442]

How did you connected PI into this amp? HDMI to chinch or what? Can it play FLAC or somehting with good quality?

[@DrCassette]

The Raspberry Pi has an analog audio output which I was using. The software I used can play FLAC.

[@tartarughaninja4]

ever opened a modern NAD receiver? they're just beautiful to look at, looks like a pc, with the main board with a lot of slot-in cards, without all those too-modern wifi usb bluetooth internet gimmicks .. just minimalistic surround receiver with great stereo sound.

[@DrCassette]

+Babalooo I don't like this modern minimalistic hifi equipment.

[@ANALOGUEAVENGER]

I too spend most of the time on these without any sense or reason. I understand you well. I have one of these and it costed me nearly 250$ in India. Trust you feel better that there are plenty like me who need help, before you. But what we like and seek, we must have. :-). Please share the cassette model you have in Video. The golden logo of 3 Head intrigues me.

[@user-bd5yg5op3h]

Шиkарно ! 👍😎

[@raymondleggs5508]

Panasonic recently started remaking technics its expensive but that is a good thing. we really dont need anymore $100.00 receivers that are sold under multiple brands anyway, that blow up after a month.

[@DrCassette]

It is ridiculously expensive. The comeback of traditional HiFi components is nice, but the prices are totally out of control. You're right, nobody needs equipment for 100 € a piece, but these days prices are at least 1000 € for something nice. That's too much.

[@zerno2348]

Sehr schöner Amp. Habe den gleichen vor einer Woche bekommen, leider in drei Einzelteilen und leicht verbastelt, da da schon der Vorbesitzer dran war, weil er vermutlich nicht ganz funktionierte und er es dann aufgab. Er hat auf der Displayplatine zum Beispiel 2 Dioden ausgelötet, fehlen zumindest. Habe zwar schon ein Schaltplan bestellt aber ob der wirklich kommt ist fraglich. Vielleicht bestünde die Möglichkeit, wenn Sie ein Service Manual haben, dass Sie mir die Werte der 2 Bauteile mitteilen könnten. Ich hab jetzt mal auf Deutsch geschrieben, da Sie ja aus der schönen Hauptstadt Niedersachsens kommen.

[@DrCassette]

+Zerno Das Servicemanual habe ich da, wenn du mir mal eine Email schickst (über Kanalseite), kann ich das weitergeben.

[@TheTechGuyYT]

Hello everyone . STK and SVI are very different matsusita spent huge money developing the SVI chips , they are quite high quality

[@bulenteskitutuncu9722]

My frend do you know whats that mean vc4 on those amps?

[@slugaool]

The SLM 1Z33 are low pass filters (2 c's and 2 coils)

[@DrCassette]

+slugaool Thanks for the info. In the schematic these are just shown as blank squares.

[@slugaool]

+DrCassette Looks like the input setup is the same www.maxdat.eu/_data/13=Kapcsolasirajzok/Technics%20SU-VX500.pdf

[@DlittleK]

elekto pusing saya melihatnya heheee, keren kak anda mahir elektro

[@lesekopf6257]

ADIEMUS!!!! NICE!!!

[@DrCassette]

Oh, let's hope this video doesn't get into copyright problems then...

[@carguyuk3613]

I bought this amp in 1988 and I still use it (in my home office). The amp is very heavy for its size. Volume control is a little scratchy but otherwise its still great. I still have a technics tuner in a matching style that I still use with it.

[@DrCassette]

These may not be the best amplifiers, but they are very reliable. I never came across a dead Technics amplifier.

[@writenamehere0000]

The only heavy part is transformer at the left. The right side is awkwardly light. Sounds like any average amp. It has lots of power only.

[@mammam6472]

...in 1991 y take one new for 45000esc. = 225 euros now and sounds great... in 2017 sounds like new is a great amp...you have find a bergain...

[@geekPlayground]

I got one in 89, for about the same price, and it is still going. I have connected to a pair of BW DM-602, and it plays very well after so many years :-)

[@Swenser]

I've got one stuck on cd input. What section could cause that? Cheers

[@DrCassette]

The input selector switch is a mechanical setup. So there must be a problem with the latching mechanism in the input selector switch assembly. Oh, and make sure the CD Direct button is deactivated ;)

[@Swenser]

@@DrCassette switch checks out ok and the mechanics. I've probed signal on aux input line with cro around tone section on preamp 8 pin chip and strangely sound comes out of speakers on another input when i do that. But stops upon removing the cro probe. I've got schematic and will play more.

[@stevenking2980]

Very nice

[@leostechnikkanal]

Im a little interested if you can repair vcrs? ( I know you arent a fixing service, im just interested!)

[@DrCassette]

Ich habe dir unter deinem entsprechenden Video geantwortet...

[@rsanchez7111]

DrCassette 🤔

[@leostechnikkanal]

@@rsanchez7111 A long story short - yes he can

[@BigEightiesNewWave]

send to 12voltvids guy Canada or NorCal715 both are excellent.

[@binya888]

I have a same, but the my amplifier is just only one side play the music! just left side! why? Which part is wrong? Thanks

[@DrCassette]

This could be caused by a bad contact somewhere.

[@binya888]

@@DrCassette ok anywhere? or just left side?

[@DrCassette]

That you will find out yourself. Carefully operate all switches and potentiometers to find bad contacts.

[@binya888]

@@DrCassette ok thx

[@carmelopiccolo7557]

I badge the sameproblem. Theresa is a bada contact in the big Cd DIRECT button

[@abrahamantoniosanchezrubio7136]

Made in japan 💪

[@Transistor512]

Be careful with the vacuum cleaner, i have heard that it generates static electricity

[@DrCassette]

+Transistor512 I know, vacuum cleaner and paint brush are far from ideal for cleaning this stuff, but I don't have access to a compressor over here, canned air does not have enough pressure and is expensive and I won't put this thing back together as dirty as it is right now...

[@raymondleggs5508]

surprised to see binding post terminals.

[@DrCassette]

This is a newer, late 80s model. As far as I know they only had those terrible twist-lock-connectors in the early to mid-80s.

[@TechnikToni-Overtribe]

that thing puts out 300 Watts

[@jorgbornefeld1689]

300 Watts heat power?

[@byCDMC]

only 44EU for this?!!! ill take two!

[@DrCassette]

+by CDMC To be honest, this amplifier is not that great, and this particular unit will need quite a bit of work to get all the dirty / scratchy switches going again. I think I paid too much for this.

[@DrCassette]

In my country (Germany) I'm lucky if I get 50€ for this once I have it all fixed...

[@justsumguy2u]

Those amps that used the all-in-one amplifier chips were awful. They don't sound as nice, and it's common for them to fail. And when they do fail, it's hard to find suitable replacements.

[@MrsZambezi]

Not necessarily!

[@XavierAncarno]

Just a reminder Kids, never open and turn on a solid state, vacuum tube amp without the lid Unless you're absolutely aware of what you doing

[@JoshuasRecordings]

+Xavier Ancarno Seriously? I done that since I was 5.

[@DrCassette]

+Joshua's Recordings Some people have different approaches. I've shocked myself with mains voltage many times, it's not too bad, a good lesson pretty much. Switched Mode Power Supplies, that's what's dangerous. If you never take apart anything, you will never become aware of what you are doing...

[@JoshuasRecordings]

+DrCassette True. What voltage do you have were you live? I have 120V where I live and that is bad enough (I think). I would recommend to take something apart, just be carful not to touch anything. Especially in a tube amp or a vintage amp/TV. I have a old TV which has the high voltage generator tube completely exposed!

[@DrCassette]

We have 230 V, in my workshop I measure 235 V. It is good practice to work only with one hand in live equipment. That way if you do touch anything, it runs through ground and not from one arm through your body and out the other arm. Because that is DANGEROUS! And it hurts, trust me, it has happened to me. And of course, anything that has high voltage in it, even if it's just a switched mode power supply, must be handled with extreme care.

[@JoshuasRecordings]

+DrCassette Absolutely!

[@sobolanul96]

I hate STK's. Once they die the amp turns into a brick.

[@DrCassette]

True. And replacement modules (if available) are very expensive...

[@int53185]

Sanyo output transistor IC pack. Looks like another Sanyo made Technics receiver.

[@sobolanul96]

Maybe part of the CEC products sold under sanyo, grundig, normende, technics etc.

[@MrHBSoftware]

its matsushita not sanyo

[@KRAZEEIZATION]

I have an 1988 Technics catalog with that in it. I have the SL-P550 CD player. Awesome. The Technics amps that came after the Class AA were supposed to be much better. The Phono stage in the 550 is nothing special. Those caps are to bring the tiny phono out put up I’d imagine. The source selection dial is frustrating small on it too.

[@writenamehere0000]

Measurements are fine on so many amplifiers of that era but they dont sound all good. I have this amp still and, its a good one for a starter who has some powerful speakers, but there wont be much crystal clear tones and bass will be muddy, not so sharp. Lots of power tho, stated 6w but feels like 120W. It was one of my first vintage amps.

[@1959Berre]

STK module... notoriously unreliable. Never (!) connect an amplifier to your precious speakers without being absolutely sure that there is no DC present on the output terminals. Those low end amps with STK power modules are not always relay protected. In case of a short in such STK you definately will fry the voice coils of your speakers.

[@MrHBSoftware]

its not stk are you blind?? its a matsushita module svi 3102

[@cekpi7]

Doesnt really matter, these integrated amps are really bad if they are not designed properly, fortunately my techincs su v2x had output protection becouse SVI module was throwing 40VDC right to relay but protection kicked it so it wasn't on terminals. It also damaged preamplifier stage and input selector.

[@MrHBSoftware]

so what? that also happens on amps with discrete transistors...svi modules are much much higher grader than stk

[@cekpi7]

Maybe, but STK-SVI chip is pretty much whole power amplifier, if something dies you have to replace whole module which is like 50-100€ alone and hard to find, discrete amplifiers are much easier to repair, much cheaper and most of the time there will only be few transistors blown but with properly designed circuitry both can be safe and sound amazing. The fact that most technics with STK/SVI modules are 30 years old and still work today just shows that, but i'm not planning on buying anything with integrated amplifier chips, its way too risky.

[@MrHBSoftware]

the era of discrete components has ended many many years ago unfortunately... your pc, your television etc they all have ICs....i dont like ICs either but between a cheap stk and technics matsushita i prefer the second one..i bought a few NOS for 20€ each so when my amp blows it i have replacements on hand...these are not bad and are not failure-prone... there are state of the art marantz amps , all-discrete component that use germanium transistors and are way worse than this...and replacing then and rebiasing the amp is not for the common mortal...usually when they short they take with them the entire preamp and power amp...replace all ten or more transistors make one mistake and you blow them all up again...so...not fun either... in the end there is nothing like a tube amp for serviceability

[@romankolosov5771]

dude, you don't even know what' you're looking at. 50watts?? joking? The back panel says 570 W consumption. Have a look at the service manual. The cooling is stare of the art. Check out the measurements...

[@writenamehere0000]

Just buy one and see..... Parts inside are not so top notch quality-. Measurements are fine on so many amplifiers but they dont sound all good. I have this amp still and, its a good one for a starter who has powerful speakers, but there wont be much crystal clear tones.

[@Camper721]

€45 ?? That is cheap.

[@danielm.4359]

Don't use contact spray. Take them apart and clean it up nicely. (:

[@DrCassette]

That's a waste of time. Disassembling potentiometers and switches and cleaning contacts that way in my experience lasts no longer than using a good contact cleaning spray.

[@BigEightiesNewWave]

@@DrCassette Yep Deoxit !

[@DrCassette]

@@BigEightiesNewWave I use Kontakt Chemie Tuner 600.

[@alcoholisfreedrink]

i bought 18000uF 200v capacitors for my new amplifier project. These are expensive...

[@DrCassette]

I can imagine those were not cheap. But why do you need 200 V rated capacitors?

[@alcoholisfreedrink]

@@DrCassette The real voltage on the capacitors will be around 70 volts and i thought 100v might not be enough. There weren't anything better available

[@DrCassette]

@@alcoholisfreedrink Hmm, if the working voltage across the capacitors really is 70 V, then 100 V rated capacitors would be perfectly fine. 200 V is an overkill.

[@alcoholisfreedrink]

​@@DrCassette I was worried about the peak voltage. 100v would have been much cheaper.

[@DrCassette]

@@alcoholisfreedrink I know, 200 V is a very unusual rating. Are these capacitors used as smoothing capacitors in the power supply?

[@writenamehere0000]

The worst amp I have ever had. Lots of power but no fidelity. Muddy, flat, weak stereo effect.

[@brucetungsten5714]

Interesting - some of the Technics amp seem to "carry" a bad reputation. Seems that the pre-amp section can be a weakness.

[@writenamehere0000]

@@brucetungsten5714 I am not familiar with electronic parts inside, but what i have read is that it has some weak parts inside, except for transformer that has lots of power (Stated 65W but when you turn the volume knob it feels like 120W). Also, my experience is it works better with some speakers that have usually highs pronounced so it levels with the amp muddiness. to some level. I actually even liked it when I connected Visaton X20 speakers (large), but then I hooked up my other vintage amps and realized it this Technics is not so crystal clear. But for any new user in vintage gear, it is a good start.