Upgrading outputs

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Hi!
A friend is working on upgrading an amp that originally used, I hope I get this right, A1106 output transistors. He was given two other recommendations: 2sd817/2SD1047's and A1368LF/C3519's. The first night be lower wattage. I am not sure. (Don't worry. He knows MUCH more than I do! :) ).
Does anyone have any recommendations for a better quality, lower nose, etc output that will plug right in? We are talking an amp in the 100 WPC range.
Thanks!
Erik
 
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Hi Erik,
There will not be a sound difference between the types. Matching the gains of the diff. pair would make a bigger (positive) difference.

Take care to clean the heatsink and insulators completely and apply new heatsink grease. I aways do a C-E and C-B leakage test on the preceeding transistors and bias transistor. If you can't do this, then just replace them. When setting the bias current, take your time while watching for excessive drift. It helps to use a variac on the first power up.

-Chris
 
bigerik said:
Hi!
A friend is working on upgrading an amp that originally used, I hope I get this right, A1106 output transistors. He was given two other recommendations: 2sd817/2SD1047's and A1368LF/C3519's. The first night be lower wattage. I am not sure. (Don't worry. He knows MUCH more than I do! :) ).
Does anyone have any recommendations for a better quality, lower nose, etc output that will plug right in? We are talking an amp in the 100 WPC range.
Thanks!
Erik
If you want to upgrade the amp, the last place to be swapping out components is the outputs. The 2SA1106 (and the complement, which I can't think of right now) is a fine output device and about anything you could replace it with will be a downgrade. Sure, you can get outputs that will handle more voltage or power, but will it make it sound better? Not likely.

Changing the outputs will have about the least effect of nearly anything else you could do with the amp.

If you insist on swapping them out, send the old ones to me.


;)
 
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Hi EchoWars,
I'm pretty sure the outputs no longer work from the text. If the outputs are good, I totally agree with you. There ain't noth'in wrong with 2SC2581 and 2SA1106 types.
Mind you, the others aren't a downgrade so much either.
-Chris
 
2SC2581...that's it. Must be getting old and feeble.

Woodang sells the original types for a pretty fair price.

If the originals are toast, by all means, slap some MJ21193's and 4's in there and call it a day...or if you want original, get 'em from Woodang. Or use the B817/D1047's. But if the originals are good, concentrate your efforts and $$ on parts of the amp where it will make a difference.
 
Depends on the amp, and its age. If its older than, say, 20 years, get rid of the old electrolytic caps.

As far as semiconductors, the difference between a decent amp and a poor one happens at the input and VAS stages. Sure, all stages are important, but the most noticable improvements will happen at the front end of the amp, not the back.
 
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Hi Erik,
Who the devil told you that? I ran a service shop in Mississauga for 16 yrs., so I know most of the characters in this market.

Anyway, to even start to advise you, we need to know what the make and model is. That way we know what the topology is and where to go. Many times, just matching transistors will do the trick. Other times there are design faults that need correcting ... or the unit may be too bad to even start messing with. It would also be helpful to know what you find lacking in the amp and what you expect when all is said and done.
-Chris
 
Be relieved! The guy who told me was not a fellow Canuck. He was a friend of a friend doen in the US of A! :)
Actually, this little amp I picked up was a big shock to me. It is the first of the Elite line by Pioneer. A77X integrated amp. 100 WPC. Three transformers. 7 independant power supplies. Yet it only cost 500 new.
Anyhow, I was at a local cash convertors, saw it there and after being accosted by the sales rep, was convinced to give it a listen. Now, this guy new squat about audio, but when he plugged it in, thru the one channel that was working, playing thru some real cheap and crappy Warfdales, this thing sounded shockingly good. With the one channel being bad, I bargained it down to about the price of a case of beer and away I went.
Gave it to a friend of mine down in Erie, PA who pronounced the sound to be shockingly good. Now this guy is a master technician, if not great tweaker, but he found when he opened it up that someone had gone to the trouble of replacing all the caps inside with new, very high quality pieces. Thus intrigued, I started wondering what this thing could do. Got the bad advice about the outputs. Got good advice about from you guys, and found out from my friend that the bad channel was caused by a screwed up selector switch, which is still available from Pioneer.
Now, the big PS caps (about 16000 mf worth) are still originals, so maybe an upgrade there would be worthwhile.
BUT, not being a fan of Pioneer at all, I was not expecting anything when I looked at this thing, and in my 20 + years as an audiophool, this thing gave me about the biggest shock I have had. Never expected it to sound as good as it did. Not in a million years.
Erik
 
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Hi Erik,
Glad you are pleasantly surprised. I normally don't expect that much out of Pioneer, but for the price ... hey. Sounds like a good one.

Before changing the filter caps, just try to bypass them with some 10uF film caps. If the selector switch is noisy, try cleaning it with a product called De-ox-id, by General Cement. I think Active carries it. De-ox-id is available in liquid (with dripper) or spray. I use the liquid the most.

-Chris
 
anatech said:
Hi Erik,
Glad you are pleasantly surprised. I normally don't expect that much out of Pioneer, but for the price ... hey. Sounds like a good one.

Before changing the filter caps, just try to bypass them with some 10uF film caps. If the selector switch is noisy, try cleaning it with a product called De-ox-id, by General Cement. I think Active carries it. De-ox-id is available in liquid (with dripper) or spray. I use the liquid the most.

-Chris

Not noisy. The selector switch (a verticle bank of pushbuttons) was quite comprehensivly trashed. Someone had tried to get creative with it and ******ed it up decidely. Got it working more or less now, but would love to get a proper replacement.

Sounds to me like my expectations for Pioneer equipment are even lower than yours. Have heard VERY little from Pioneer that I do like. This was a jaw dropping experience. I would love to hear an original to compare it to this thing. Would love to know how it would compare. I wonder how much of the sound I heard is due to the mods. My tech friend said the third transformer is for the pre-amp and phone section. About the only area that hadn't been played with. He is taking a look at it now.

Why the 10uF film caps?

De-ox-id is AWESOME stuff!

Thanks
Erik
 
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Hi Erik,
The 10uF bypass caps should improve the audio characteristics of your power supply. Many times this is all you need to do, depending on the quality of the equipment.

I also do not expect much from Pioneer equipment. All their gear tends to sound bad, old or new. They generally tend to run regulators way too hot. The older stuff tends to sound "thin" on top of other nasties. But I will always give a manufacturer a listen in case they slip up and produce a winner.

cunningham,
It's not the parts so much, but the circuit design and lack of heatsinking that determines what I don't like about Pioneer. They used to make a better set, but then so did everyone else. I was lucky enough to work on Marantz 500's, 2500's and lots of other heady pieces of gear that truly rocked. That's what put the fun in HiFi servicing. Not so much any more. I'll settle for stuff that sounds good even.

-Chris
 
anatech said:
Hi Erik,
The 10uF bypass caps should improve the audio characteristics of your power supply. Many times this is all you need to do, depending on the quality of the equipment.

I also do not expect much from Pioneer equipment. All their gear tends to sound bad, old or new. They generally tend to run regulators way too hot. The older stuff tends to sound "thin" on top of other nasties. But I will always give a manufacturer a listen in case they slip up and produce a winner.

cunningham,
It's not the parts so much, but the circuit design and lack of heatsinking that determines what I don't like about Pioneer. They used to make a better set, but then so did everyone else. I was lucky enough to work on Marantz 500's, 2500's and lots of other heady pieces of gear that truly rocked. That's what put the fun in HiFi servicing. Not so much any more. I'll settle for stuff that sounds good even.

-Chris


Hi again.
My tech sounds much like you. He started back in the late sixties and was factory authorized for Marantz amongst so many others back in the heyday. He doesn't impress easily, but this thing has shocked him too. Says the circuit looks like nothing he has seen in a Pioneer before. He wonders who the designer was.
Will pass on the tip about the 10uF caps. Thanks!
Erik
 
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