Sony TA-5650 MOSFET

[coffeemachinist]

Further Information: 

 

Here we have the famous Sony TA-5650 integrated amplifier.

 

This amp came to me with a blown output stage, which is the usual fate of this era sony v-fet amplifiers without intervention to replace certain diodes in the biasing circuit.

 

With the help of Tonny in the Netherlands, this amp has been converted to run mosfet outputs, using genuine Hitachi vintage T03 devices supplied by Tonny when I asked nicely and paid the ransom.

 

I previously had a fully refurbished Ta-5650 with original v-fets and I can tell you this one is as good if not better, particularly in the low end. Add to that the robust reputation of hitachi mosfets and you can’t go wrong. I wanted to save this brilliant amp as v-fets are unobtainium, and this was a great way to go.

 

The v-fet in the phono section is retained, all else is original. It sounds simply wonderful and has been running happily for nearly a year of daily use since the conversion.

 

Here’s what Tonny has to say:

 

Conversion for Sony

TA-4650 / TA- 5650 / Wega V-4810

Replacement from 2SJ18 & 2SK60 → Hitachi (2SJ50 &2SK135),

Exicon (10P20 &10N20) or Magnatec (BUZ901 & BUZ906)

Advantage:

1. Hitachi's are still very good and inexpensive available.

2. much more robust transistor close too indestructible.

3. Much lower internal resistance, which also suits 4Ω loudspeakers.

4. Sound quality is better than the original and special in the lower area.

This conversion is delivered in PDF format via email with a circuit diagram and photos.

In addition, a pair tips for idle current adjustment.

To date, more than 15 pieces of TA-4650, 6 pieces TA-5650 and 1 Wega V-4810

were rebuilt with positive results.

There are also some instructions for TA-8650 and TA-5550,

but no one of these were yet rebuild.

 

Notes on condition-

 

The top lid has been repainted previously.

 

There is a lightly engraved serial on the top right surface of the faceplate. Not noticeable from the front. Otherwise the faceplate is very clean and all knobs/switches clean, undamaged and original.

 

The vinyl side cheeks are present and will be included, they are a bit tatty though.

 

Given there are some cosmetic flaws, the pricing is sensible.

 

Collect and audition in Northcote VIC 3070, postage available

[hrumph]

Very interesting! 

Is this still 50W?

[coffeemachinist]

Hi Mark,

 

The output devices fitted are good for over 100w/channel but obviously the power supply rails will be the limiting factor here. Suffice to say it's got plenty of power on tap.

[hrumph]

Yowza! 

 

What did it measure before clipping when you were testing it?

 

Thanks for getting back to me.

 

[Tedded]

Hey

Thanks so much for the detailed info, very handy

GL

[mfforever]

Wow .... there's  a whole lotta love in this amp ..........     great to see fantastic vintage pieces ( like me I dare to venture ) are still being rebirthed to sound wonderful for a couple of more decades ...... really appreciate the passion here and I'm sure the sound is glorious ........    I had a 1980  Technics 20 Watt amp and it really was surprisingly detailed and delicate ......... GLWTS

Edited September 5, 2023 by mfforever