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Sony TA-1150 Build Thread

Lavane said:
Who knows, the protection might be better than a relay.
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Having since owned a TA-1150 l can confirm that indeed these thermal circuit breakers do seem to work better than other types of protection circuits. I say this because l sold the TA-1150 to a guy to contacted me saying one channel was cutting in and out and he heard a clicking noise and light flash coming from within the amplifier. Upon further inspection he found that his speaker wires were in poor condition and were shorting. The poor old TA-1150 still worked perfectly after this was rectified, l would say with a fair amount of confidence that most vintage amplifiers would not have survived this episode without component failure.
 
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Oldsansui441 said:
Having since owned a TA-1150 l can confirm that indeed these thermal circuit breakers do seem to work better than other types of protection circuits. I say this because l sold the TA-1150 to a guy to contacted me saying one channel was cutting in and out and he heard a clicking noise and light flash coming from within the amplifier. Upon further inspection he found that his speaker wires were in poor condition and were shorting. The poor old TA-1150 still worked perfectly after this was rectified, l would say with a fair amount of confidence that most vintage amplifiers would not have survived this episode without component failure.
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Realistic used thermistors in a lot of the amps and receivers they sold.
One RS integrated I restored and gave to my son had thermal protection.
The amp didn't like 4 ohm loads at higher volumes and would shut down. The amp still works fine. Another RS integrated I have that I use in my garage would shut down after 10 or more minutes. After replacing the voltage regulator and caps in the power supply it's been running fine. Relays just seem to save mostly components up stream from the outputs and drivers.
 
MBuras said:
First up is the main amp board. It's mounted to the output heatsink on the bottom level of the amp. There are about 8 wires attached to this board, thoughtfully with friction fit connections, and then 4 screws on the heatsink and the whole assembly comes out.

View attachment 886204

View attachment 886204

View attachment 886205

To remove the main amp board from the heatsink you have to pull the tab screws for all the output transistors. There are also 2 additional screws on that section of the heatsink. And then the output transistors need to be pulled out of their friction fit with the board below. Then the amp board pretty much falls away. Very simple.

Once I started trying to document the amp board vs. the service manual and schematic parts list I ran into a problem. My board has extra parts not listed on the documents I have. Hmmm....turns out after a little research that Sony made running changes on this amp over its production run and created a revision some refer to as the TA-1150D or just TA-1150 Revised. That made sense as this one has a high serial number. But nowhere online was I able to find a revised service manual or schematic. That is until I used Google Translate to check out a Japanese website. The page appeared to be a very technical analysis of the amp and/or the revisions but the real bonus was a schematic image of sufficient quality to use as a reference source. Sure enough it's exactly what I needed.

View attachment 886212

So here is a verified list of most components on TA-1150 amp board with serial number 806823.

C301/C401 - 0.47uf/50v electrolytic capacitor
C302/C402 - 10uf/10v electrolytic capacitor
C303/C403 - 3pf/50v ceramic capacitor
C304/C404 - 47pf/50v ceramic capacitor
C305/C405 - 220uf/10v electrolytic capacitor
C306/C406 - 4.7uf/25v electrolytic capacitor
C307/C407 - 100uf/50v electrolytic capacitor
C308/C408 - 47uf/50v electrolytic capacitor
C309/C409 - 0.033uf/50v mylar capacitor
C310/C410 - 0.01uf/50v mylar capacitor
C311/C411 - 27pf/50v ceramic capacitor
C551 - 47uf/50v electrolytic capacitor
C552 - 220uf/50v electrolytic capacitor
C560 - 220uf/6.3v electrolytic capacitor

Q301/Q401 - 2SC1362 transistor
Q302/Q402 - 2SC1362 transistor
Q303/Q403 - 2SA678 transistor
Q304/Q404 - 2SC945 transistor
Q305/Q405 - 2SC1124 transistor
Q306/Q406 - 2SA706 transistor
Q311/Q411 - 2SA678 transistor
Q551 - 2SA678 transistor
Q552 - 2SC945 transistor
Q553 - 2AS678 transistor

R308/R408 - 1.2K 1/4 watt resistor **
R310/R410 - 270 1/4 watt resistor **
R312/R412 - 100 1/4 watt resistor **
R316-R319/R416-R419 - 0.47 2 watt emitter resistor (upright)
R322-R323/R422-R423 - 470 1/2 watt resistor
R324/R424 - 10 1/2 watt resistor
R325/R425 - 4.7 1/4 watt resistor **
RV301/RV401 - 1K trimmer

** = these resistors may or may not be covered in some of the glue from nearby capacitors. I am replacing due to some corrosion of leads from glue.

D301/D401 - SH-1S diode
D555/D556 - 1N4148 diode
D557/D558 - 10E4 diode
D559/D560 - 1N4148 diode

Output Transistors:
Q307/Q407/Q309/Q409 - 2SC1060 transistor
Q308/Q408/Q310/Q410 - 2SA670 transistor

And if anyone knows of a more modern solution for those goofy spring metal overload protectors on this board I'm all ears. Seems like they would react way too slow to any potential short, possibly risking damage to the speakers.
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Thank for this useful thread; I am in the process of rebuilding an TA-1150 myself, but I don't see C560 (220uf 6.3V) on the amp board that you've listed. Am I missing something?
 
There are a few different versions of this amp so maybe yours doesn’t have one? On mine, in the amplifier board picture, it was just in front of that huge cap in the middle of the board near the heat sink.
 
MBuras said:
There are a few different versions of this amp so maybe yours doesn’t have one? On mine, in the amplifier board picture, it was just in front of that huge cap in the middle of the board near the heat sink.
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Thanks for the response MBuras. Definitely not on my amp board. Just one 220uf 50V and two 220uf 10V, no 6.3V. I finished the recap, along with a handful of scorched 820Ω resistors on the toneboard. I'm wondering if you found the phono section gain a little lower than expected? I assume the life of the IC on the phono section is in question. Any known replacements for the two ICs on the Pre/EQ stage?
 
tonefoto said:
I'm wondering if you found the phono section gain a little lower than expected? I assume the life of the IC on the phono section is in question. Any known replacements for the two ICs on the Pre/EQ stage?
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I don’t recall thinking there were any issues with gain but can’t verify because I sold the amp to support my audio habit.

Not all IC’s are bad. I’d assume there might be a better replacement these days but never got as far as researching that.
 
Apologies to revive this thread, did you replace driver transistors c1124 + a706 with c4793 a1837 or something else? I recently blew my power amp and replaced c1061 with h1060 + a671 and driver transistors as well but it keeps blowing out my output transistors.
 
My notes show I used ksc2690ays and ksa1220ays for replacements (pinout is different!). I do know Sonys seem to be finicky about drivers and outputs. Although this one worked fine I’ve had problems subbing modern transistors with other Sonys since then. You might create a new post and see what everyone currently uses. Maybe a better solution has been found.
 
Very nice detailed work. I am in the process of removing faceplate as some function buttons are stuck during deoxit attempt. I have difficulty removing tone control knobs. I do see they have small screws. Do I need to remove them?
 
antimatter55 said:
Very nice detailed work. I am in the process of removing faceplate as some function buttons are stuck during deoxit attempt. I have difficulty removing tone control knobs. I do see they have small screws. Do I need to remove them?
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it’s been 5 years so my memory is a little fuzzy on this one. I think the outer cap on the tone control is just pressure fit. The inner section probably has a set screw (Allen head?).
 
MBuras said:
it’s been 5 years so my memory is a little fuzzy on this one. I think the outer cap on the tone control is just pressure fit. The inner section probably has a set screw (Allen head?).
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Yes, I need to unscrew them, there are two each for the inner cap. They are not Allen, may be flat or Fillister? Thanks for your photos, it helped me in removing buttons and knobs. I am no electrician, so not going to mess with caps, just deox, clean internals and assemble back. I would later ask around repair shops how much it would cost to service and replace caps.
 
i know this is a very old thread, but @MBuras you are a vintage amp god. i love reading your restoration threads (and the Marantz 1122DC one was happily used for my own recently).

i appreciate you and hope you are well mate!
 
I am in the middle of recapping a TA1150 and was interested to note that the bias transistors on the unit pictured were also without any kind of mechanical pressure mechanism for assuring good thermal contact to the heatsink. Sony's approach of simply standing them next to the heatsink and applying thermal grease seems out of character for an otherwise nicely built amplifier. I am debating drilling a couple holes astride each to loop a wire to pull them snugly to the heatsink.

The tilt-down front sub-assembly made working on this much easier than I expected when I first took the cover off :-)

Thanks to all for the experiences shared.
 
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