A friend asked me to fix her Toa model KD-1 integrated combo amp. She plays Cello in a local quintet.
This unit has one mic input, four RCA type inputs an amp, and a 12" speaker with a secondary small cone (forgot what hey are called) attached to the same voice coil. TOA had a good rep back in the day,
Anyway, the power amp is bad and it has one of those dreaded (IMO) STK modules which is a complete audio amp in an lage hybrid IC package.
I've only heard how unreliable these modules are. I suspect the run away thermally?
It has the STK 3046V. specifically which doesn't seem to be available.
What's the scoop on these things. There appears to be many variants. Do they all have the same pinout?
Should I attempt replacing with a different variant.?
If I owned it, I'd replace the module with a class D amp I suppose. I'm not willing to put that much time in someone I'm working on for free for though.
This unit has one mic input, four RCA type inputs an amp, and a 12" speaker with a secondary small cone (forgot what hey are called) attached to the same voice coil. TOA had a good rep back in the day,
Anyway, the power amp is bad and it has one of those dreaded (IMO) STK modules which is a complete audio amp in an lage hybrid IC package.
I've only heard how unreliable these modules are. I suspect the run away thermally?
It has the STK 3046V. specifically which doesn't seem to be available.
What's the scoop on these things. There appears to be many variants. Do they all have the same pinout?
Should I attempt replacing with a different variant.?
If I owned it, I'd replace the module with a class D amp I suppose. I'm not willing to put that much time in someone I'm working on for free for though.
Replacing the whole power amp section with a new amp module may be the simplest and easiest fix. If you do locate a new STK module it will probably be a FAKE, and even less reliable than the original. The construction of those original modules is wrong on so many levels that it’s a wonder they last as long as they did. Modern reproductions (fakes) are even worse.
There has been success with people building “replacements” for them out of discretes, using construction techniques and proper parts which are reliable, but it’s a lot of work for a freebie. Can’t say I recommend doing it unless you were *really* attached to that amplifier.
How much supply voltage does that power section use, and what speaker impedance? That will give you some idea of what you could build into it in place of the STK module.
There has been success with people building “replacements” for them out of discretes, using construction techniques and proper parts which are reliable, but it’s a lot of work for a freebie. Can’t say I recommend doing it unless you were *really* attached to that amplifier.
How much supply voltage does that power section use, and what speaker impedance? That will give you some idea of what you could build into it in place of the STK module.
The STK 3046 is not on the net, please check the number again.
Those are mostly two amps in the same module, so it may be bridged stereo.
You have a single set of speakers, 12" cone would be about 40 watts RMS...check the supply, and get an appropriate Mosfet or Class D module. Check for mono in and out levels.
Check the power supply first, STKs have been known to take out power supplies too...so that also may be needed.
Except the LM1875, there is a shortage of Class AB chip amps, and many Class D from China are also fake chips, though some are said to be of good quality.
Those are mostly two amps in the same module, so it may be bridged stereo.
You have a single set of speakers, 12" cone would be about 40 watts RMS...check the supply, and get an appropriate Mosfet or Class D module. Check for mono in and out levels.
Check the power supply first, STKs have been known to take out power supplies too...so that also may be needed.
Except the LM1875, there is a shortage of Class AB chip amps, and many Class D from China are also fake chips, though some are said to be of good quality.
On the cheap, you can find an old amp with one working channel, and use the inner parts for this one.
Or buy an old or new party speaker. New will be $40 and up.
Those are speaker with amp, with wheels, some have a battery too, you can go to the beach with them.
Ideal for a musician, those are intended for travel and rough use.
Or buy an old or new party speaker. New will be $40 and up.
Those are speaker with amp, with wheels, some have a battery too, you can go to the beach with them.
Ideal for a musician, those are intended for travel and rough use.
My mistake typing - it's a STK4036V.
I don't see any of that part number on the net.
Perhaps someone could direct me to a spec sheet that explains the variants. That would be a start.
I don't see any of that part number on the net.
Perhaps someone could direct me to a spec sheet that explains the variants. That would be a start.
NTE7030 Module - 2 Channel 50w Audio Power Amp 15-lead Sipvcc = 35v Typical
Claims to be equivalent
I still say Mosfet mono amp.
+/- 35V, 50W, your mileage may vary...
Claims to be equivalent
I still say Mosfet mono amp.
+/- 35V, 50W, your mileage may vary...
Sanyo STK Amplifier Schematics – Electronics Projects Circuits
There is a link for full list there.
The V suffix means a slightly different power supply or output rating.
Check the supply first.
There is a link for full list there.
The V suffix means a slightly different power supply or output rating.
Check the supply first.
+/- 35 V means a TDA 7293 or 7294 will work.
IF you can get hold of a genuine one.
Those are mono, the output is sufficient.
7294 also blow up, take care.
IF you can get hold of a genuine one.
Those are mono, the output is sufficient.
7294 also blow up, take care.
Yes, those will work.
Also good to determine what was the original cause of failure to prevent it happening again.
+1
You can safely use the ECG7031 which is 100% equivalent to the STK4036V, the external shape of the case may be slightly different but mechanically it will fit perfectly.
ECG7031 MOD-100W AUDIO PO | eBay