Do brand mismatched output transistors affect anything?

Captain581

Captain581

Active Member
I just purchased a gorgeous 2265B that admittedly look good - almost like new. Sounds good too, although maybe not quite as ear-friendly as my 2252B, which I just sold. Might be the BIAS, which I'll have tended to.

I paid top price for this 2265B (too afraid to admit how much). I was told it was all original, save for the LED light-bulbs. However, today I popped the top and noticed that the original output transistors have all been replaced; I could see the white surrounding grease has been disturbed, and three (3) different brands of output transistors have been used on the job - looks to have been done quite a while ago. One channel had matching parts, the other, both output transistor were different brands.

My question: Do mismatched replacement output transistors this value, and/or sound? Shouldn't output transistors match when they're paired for either left or right side?

I'm not quite as confident/pleased with this purchase as I was before lifting the hood, and had to sell 2 units to be able to afford it.

Any info welcome.
 
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I think that ideally they should be matched. However, I see them all the time where one output has been replaced, and they usually sound fine. If it were mine, I would probably be driven to replace them on that channel with a new pair.
 
What you hear is more likely to be affected by what you see (think McGurk effect) than the slight difference in the transistor specs. The warm Marantz sound is locked in by all of the preceding circuitry so unless the transistor specs are way off and you can hear it, you can safely leave it be. That being said, my logic to replace (after thoughtful consideration) follows:
  1. I wouldn't bother if it's an old repair with the same part number of the same vintage, but different brand. Repair techs at that time had access to direct replacements and I agree: if it ain't broke, don't fix it. It made it this far after all.
  2. If it's a different part number, I would compare the datasheets vs the original to see how different they are. If they are comparable, I wouldn't bother.
  3. If the replacement specs are way off vs original *and* I can definitely hear it, I would swap it out with the best match I could find to keep the specs consistent with the purpose of the circuit.
You can always go on a listening binge for a couple+ hours. Let it come to full operating temperature and put it through its paces with material you know. Reserve judgement for after a good listening session. It really all comes down to what sounds good to you and having material you know to compare against will help you make that determination.

EDIT: Fixed #3. Inserted "the best match I could find".
 
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Yes Nope!

I appreciate the intelligence of your reply, especially the “...warm Marantz sound...” statement. What a great sentence. I wonder if anyone else would have phrased the idea quite so succinctly. And I was somewhat reassured, since you honed in on my particular concern - losing the signature Marantz sound.

Didn’t know about the McGurk effect but do now, and it’s not in play in this case. I now have only two receivers left, both hooked up and running: the ‘new’ 2265B and a Sansui 5900Z. Unfortunately for me, the 2252B I just sold sounded more transparent and detailed than this new 2265B does. It was the best of the three.

As per your suggestion, I spent a few hours listening and comparing last night. To approximate the sound of my Sansui 5900Z and the departed 2252B, I have to turn up the treble 2 notches on the 2265B; still, some of the nuance and detail is lost by comparison.

It could be it needs the BIAS and DC offset adjusted, and I’m getting that done by my local tech soon. Still, I think this unit just had a lot more use that the ‘rusty inside but beautiful outside’ 2252B I sold. BTW, all were still using original caps. Maybe a recap would restore the ‘sparkle’ that the 2252B had, but that’s out of the question presently. It’s never ending, isn’t it?

OsciloNope said:
What you hear is more likely to be affected by what you see (think McGurk effect) than the slight difference in the transistor specs. The warm Marantz sound is locked in by all of the preceding circuitry so unless the transistor specs are way off and you can hear it, you can safely leave it be. That being said, my logic to replace (after thoughtful consideration) follows:
  1. I wouldn't bother if it's an old repair with the same part number of the same vintage, but different brand. Repair techs at that time had access to direct replacements and I agree: if it ain't broke, don't fix it. It made it this far after all.
  2. If it's a different part number, I would compare the datasheets vs the original to see how different they are. If they are comparable, I wouldn't bother.
  3. If the replacement specs are way off vs original *and* I can definitely hear it, I would swap it out with the best match I could find to keep the specs consistent with the purpose of the circuit.
You can always go on a listening binge for a couple+ hours. Let it come to full operating temperature and put it through its paces with material you know. Reserve judgement for after a good listening session. It really all comes down to what sounds good to you and having material you know to compare against will help you make that determination.

EDIT: Fixed #3. Inserted "the best match I could find".
Click to expand...
 
I am glad I could help. I pointed out the McGurk effect only as an example that our perceptions of sound are malleable.

I agree that a recap would help. 40+ years for electrolytics under ideal conditions can be a crap shoot. When you don't know the previous owner's listening habits and the device's environmental conditions, a recap is almost obligatory if it has original caps.
 
I always replace mismatched outputs because they look bad. Whether or not it has any effect on the sound I can’t tell you. I just don’t want someone to look at a piece I went through and think it looks trashy. It’s like putting different caps on one channel vs the other. It just looks bad.
 
Captain581 said:
My question: Do mismatched replacement output transistors this value, and/or sound? Shouldn't output transistors match when they're paired for either left or right side?
Click to expand...
If their specs and type are comparable, no they have no effect on the sound. A substitute of equal, or better of the same brand/type is fine. However differing brands/types with differing manufacturing processes can sound different when used in the same unit on one channel. What is more likely to make it sound "flat" in comparison to the 2265B, is aging electrolytic capacitors. Replacing them with quality modern caps will make a world of difference as long as you use the proper types in their corresponding circuits. What are the brands and number of the "mismatched" ones? If the originals are 2SA/2SC, and the replacements are 2SB/2SD, then yes, they very likely will sound somewhat different, but not by much. They are high frequency vs low frequency devices.
 
EastPoint said:
I always replace mismatched outputs because they look bad. Whether or not it has any effect on the sound I can’t tell you. I just don’t want someone to look at a piece I went through and think it looks trashy. It’s like putting different caps on one channel vs the other. It just looks bad.
Click to expand...

Bingo, even if it doesn't affect sound, it certainly affects value because it is half-assed.
Some Marantz are also fairly sensitive to output transistor matching, with production tolerances being a whole lot better these days you can get away with just buying them all at once (same lot), but I wouldn't fully trust mismatched manufacturers.
 
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