Sony amp

[Dave Hewitt]

Hi,just a few observations regarding amps,I'v been interested in valve amps forthe last few years with just the occasional venture into transistor amps in the shape of a Pass f3 clone which I thought was very good.Yesterday I remembered that I had a Sony Ta f7 vfet amp residing in the airing cupboard.I thought I would give it a whirl,carted it downstairs connected it up,switched on and all I can say is things have not progressed much in the last 30 years.The sound was amazingly good with none of the hash that one gets with normal tranny amps,in fact it could have been a very powerfull valve amp.I also noticed that the pass amp didnt have this transistor hash which I would describe as something you cant actually hear,but know is there.Anyway will be giving the old Sony an extended listen and as for build quality its first class.
Dave.:)

[Alex_UK]

Nice one Dave, and I bet it has gorgeous VU meters... I've got a TA-F4A which although it is post-VFET, still demonstrates (as you have said) that not much has progressed really - or maybe the 70's was just the "golden age" of hi-fi?

[Ian Walker]

Dave..Could you give me first dibs on that if you want to make room in the airing cupboard ;)

DJ E.

[Dave Hewitt]

Hi Alex,I think you are quite right these mega amps from the seventies seem to have far more substance to the sound than todays jobs which always seem thin sounding to me,the makers today seem to be hell bent on max detail retrieval and not so bothered about the rest of the sound,ie no bass and screechy treble.Yes it has big vu meters and tone controls as well which we all know you shouldnt have.as they make the sound worse :scratch:
Dave.

[Dave Hewitt]

Hi Ian,Been and had another look in the cupboard,found two sansui tuners,a pie on here tuner and a pie on here sa 9500 as well as a yammy ca 1000,cant find any big tannoys though,but theres a big jvc amp skulking under a towel.Might be retiring the valve amp for a while.:)

[Alex_UK]

Yes it has big vu meters and tone controls as well which we all know you shouldnt have.as they make the sound worse :scratch:

There's even some sort of "Filter" control on mine! :eek:!

http://muare1.vcmedia.vn/images/57/ta-f4%5B1%5D_1274778360.jpg
(Picture nicked from the web - but to me a beautiful looking amp, and timeless design)

It especially loves vinyl (My 401 is currently connected, just needs a nice pair of Celestion Ditton 44s or similar, I feel, for the correct period system) - maybe I should drag mine downstairs again... (crap speaker spring clips though...)

[ourdogmax]

Bloody hell, Alex, that's a lovely looking amp.:)

[swampy]

nowt wrong with a good sand amp done right and tone controls are damn useful in some rooms and setups.

Some hi end amp makers like krell and copland have recently started doing room correction systems... re....graphic equaliser in a new form.

[DSJR]

Valves are sand amps - what do you think the glass is derived from?????

The Sony V-FET amps were a class apart from anything else they made - the standard models they did in the 70's were thin-toned rubbish as were most of the Jap competition of the times. HOWEVER, the V-FETS always costed dearly if any failed and I've read that there are some diodes that ought to be replaced on amps like the TA-5650, which was a lovely amp. I remember a £120 Sony integrated from the early nineties which worked very well with passive ATC's because of its grunt, but (apologies Alex), I don't remember many of the TA-F Sony's being that good.

[Ali Tait]

The sand bit refers to the silicon in the transistors that the signal.passes through,rather than the vacuum of the valve.

[StanleyB]

I still use a VFET power amp and have been doing so for decades. It's far better sounding than MOSFET and transistors.

[Reid Malenfant]

I'm assuming you mean in your opinion vfets sound better than class B or AB amplifiers with mosfet or transistor output stages :scratch:

If so i'd probably agree with you. Output stage quiescent current tends to be higher (or can be higher) with vfets due to there inherent negative temperature coefficient. They are also much easier to drive due to lower gate capacitance than most mosfets which is beneficial also.

It probably explains how come the old Maplin 150W vfet amplifier kit was so popular :eyebrows:

[DSJR]

Can you still get V-FET's?

Anyone who now drives the price of the Sony's upwards would need to get them serviced while they're working. I understand the output trannies came in very expensive matched sets and for a couple of diodes to check and replace (from summat I read on t'web), well worth doing. The 5650 and 8650 (less in the latter case) didn't like floppy, bassy speakers, but I suspect they'd love IB type speakers and "proper" Tannoy DC's with the lighter cones and corrugated surrounds :)

[Rare Bird]

You can pick up say 2SK60/2SJ18 if you look hard enough

[Reid Malenfant]

Can you still get V-FET's?
Yes :) It might not be easy to source stuff like the 2SJ49 or its complement the 2SK134 or other slightly different voltage vertions of the same thing, but other manufacturers make them.

BUZ900 & BUZ905 are exact copies & readily available, there are plenty of others as well including TO3P types ;)

[swampy]

It probably explains how come the old Maplin 150W vfet amplifier kit was so popular :eyebrows:

The Maplin kit was Mosfet BTW, not Vfet. It was based on the Hitachi application notes for the 2 output transistors used in the kit.

It was popular. I made one which is still in use today 20 years later by a relative.

[Dave Hewitt]

The 2sj 49 are not v fets they are Hitachi mosfets.
Dave.

[Dave Hewitt]

It appears that replacement v fets should have the same pinch number as the one its going to replace.Dont know what the pinch number refers to but probably is something to do with matching so that with parralel output devices they share the current equaly and one is not doing too much compared to the other.
Dave.:scratch:

[Reid Malenfant]

Oooh cripes :eyebrows: You chaps are right, just remembered they are lateral mosfets :doh: Just ignore me :mental:

[Vinyleyes]

Anyone know if this Technics SU 7300 is a V FET amplifier.

http://cgi.ebay.co.uk/Rare-Technics-SU-7300-Intergrated-Amplifier-1977-78-/260704660004?pt=UK_AudioTVElectronics_HomeAudioHiF i_Amplifiers&hash=item3cb3356a24

Thanks

[DSJR]

Unless something has happened to it in its life, its a crude sounding, post 1975 Jap special, all thin and tinny as was the 7600... memories can and do fool me, but the Japanese ranges we received in the UK after the VAT increase that started the long decline of our industry never quite reached the heights of some of the products from before. This doesn't mean that the great stuff wasn't being made, but IMO the importers possibly thought that the market wasn't there in the UK so didn't bother, except for a very tiny number of items cobbled probably from their main European distributor (in Germany?).

Sony made the 5650 and 8650 which we saw here at the same time of the first valve resurgence in c1975. I understand from Vintage Knob that there was also a 4650 in the US and also mk2 versions which we never saw. There may have been later ones as well, but I'm afraid I know nothing of them. of course, by the 80's, all the top end far eastern gear was all but totally ignored in the UK, such was the dominance of outspoken UK brands holding us back, together with an equally snotty US contingent - IMO.

[Vinyleyes]

Thanks for helping me out there Dave ..... on both posts .... :cool:

[Dave Hewitt]

Hi,I would have to agree with Dave on this.
Dave[another]

[StanleyB]

One of the hidden gems of the 70's era is the AIWA AA8500 and AA8700. The AA8700 was the best and most expensive amp Aiwa ever made as far as I know, and I happen to have three of them. Unfortunately each one has a minor blemish of sort, so I hope to make a pristine one out of the three after the new year and post pics of it.
But if you ever come across the AA8500 or AA8700, it's worth a punt if it is in full working order.

[ourdogmax]

I actually have a quiet appreciation for Technics gear, I worked for a Matsushita retailer and repair shop for around 15 years.
But have to agree most of the gear from the 70's era was crap.
Amplifier wise, that is.
:)

[StanleyB]

The cheaper ones were. The good ones used to cost a month's or two wages and not many were sold.

[Reid Malenfant]

I actually have a quiet appreciation for Technics gear, I worked for a Matsushita retailer and repair shop for around 15 years.
But have to agree most of the gear from the 70's era was crap.
Amplifier wise, that is.
:)
Hi Darrell, seeing as you mentioned this, do you mind if i ask a question? :scratch:

Did the Technics SE-A1 power amplifier (http://audio-database.com/TechnicsPanasonic/amp/se-a1-e.html) ever go into production? I have seen pictures of it & i believe i even have the circuit diagram but even though the thing is like rocking horse sh*t i can find anything on anyone actually owning one :rolleyes:

Just in case you don't know it the spec is 350W RMS per channel 8ohm class A, but it had a seperate low voltage PSU for the class A circuit so dissipation wasn't through the roof. Just found & added a link ;)

[StanleyB]

I can answer that one, since I spent about 8 weeks fixing one for a customer when I was at Lasky's Servicepoint. JUst about every transistor was blown. I had to use a trolley to cart it about.
The Harman Kardon Citation XX was however far superior in built and sound quality.

[Reid Malenfant]

I can answer that one, since I spent about 8 weeks fixing one for a customer when I was at Lasky's Servicepoint. JUst about every transistor was blown. I had to use a trolley to cart it about.
The Harman Kardon Citation XX was however far superior in built and sound quality.
:lolsign:

Yeah well it was a typical high feedback jap design from what i can establish so it's not surprising it didn't cut the mustard ;)

Quite a few transistors from what i can see to (read bloody loads with two amplifiers per channel), would have been a damn expensive repair :doh:

Cheers Stanley :)

[ourdogmax]

Mark, I never clapped eyes on one.

You wouldn't believe how many models there were.

6 filing cabinets full of schematics.

I wish I could have saved them when the firm went down, bugger :doh:

[Reid Malenfant]

6 filing cabinets full of schematics.

I wish I could have saved them when the firm went down, bugger :doh:
Not to worry, most was just jap crap anyway :eyebrows: If ever a firm had a good idea but totally f*cked up the implementation then that was it ;)

You'll be seeing the schematic for one channel shortly ;)

[Dave Hewitt]

Di Doo.:ner:

[ourdogmax]

Well Mark, some of it was better than the screechy anaemic sounding shite from Britain.

One of the worst offenders had to be Audiolab with there wonderful 8000A. (had one)

Linn LK series (had some)

We were all told in the 80' this black box and that black box was better than anything else.
Pfft, in the words of Jim Royle, "MY ARSE".

And there are many company's, gone the way of the DODO.

Is it because of of reliability issues, probably.

more likely people caught on to the con.

£500 for a Brit(ttle) dodgy box or £100 for something that may not tick every box sonically. But will still be working in say, 30 years time.

I'm not saying all Brit hi-fi is that way.
It just seemed to be a problem at the time. All detail and no enjoyment.

I now use Chinese valve amps 10 wpc, and have never been happier.

Iv'e had all sorts, now, Iv'e never had an amp over £20000.
So if you're rich and can afford owt, ignore this.

If you're on a budget, like me don't ignore Asian audio.

YOU CAN MUCH WORSE AND PAY THROUGH THE NOSE. :goodnight:

[Gromit]

Slight thread resurrection here - just scored myself what looks like a rather sweet Sony TA-F670ES, along with matching ST-570ES tuner. The tuner may not get used as I don't have a suitable aerial but the amp, I'm really looking forward to it and will be something of a departure for me being Japanese and with plenty of watty things coming out of its speaker sockets. :)

Chap's bringing them down to our place on sunday - and the amp will be at Scalford, sharing duties with the Claymore.

While I'm here, does anyone know much about the Sony CDP990 please? I think it was their top model, below the ES stuff, and wondered if it might make a nice transport to use with the Dacmagic. :)