What about so called audio output transistors ? - Page 2

Enzo · 16th October 2019, 10:26 PM

If you want to buy a few thousand transistors from Toshiba, you can have your name on them, just as Luxman did.

analog_sa · 16th October 2019, 11:05 PM

Quote:

Originally Posted by georgesgiralt

I've heard some Luxman nerds

I know nothing about Luxman nerds, but the Krell nerds advise against replacing the outputs with Motorolas. And for a good reason.

It is not impossible the Luxman transistors have a tighter match for Hfe than random batches from Toshiba.

As for replacing 2SD716/2SB686 with TIP and believing nothing has changed...the only conclusion i can draw is you don't really listen to your amps.

georgesgiralt · 17th October 2019, 12:47 AM

"As for replacing 2SD716/2SB686 with TIP and believing nothing has changed...the only conclusion i can draw is you don't really listen to your amps. "
I didn't say that. I just said that it works and is about as powerful as it should. As I could not find the correct part (except from ... China .... ) and as I had these, I put them in. But I'm well prepared to put better ones if you can spec them. (and I can find them easily)

wg_ski · 17th October 2019, 03:57 AM

Looking at the data sheet I saw nothing special about the original parts, other than they were 60 watt devices. Back in the day they were probably cheaper than the typical 130 to 150 watt TO-3P’s. Any of the typical “audio amp application” TO-3P devices is probably better than the TIPs, which are generic and have very loose specs. They vary greatly from one batch to another. Even amongst real ones (ST uses more than one fab, and you get something different from them that meet the loose spec. ON may do the same, but I don’t have units with different origin codes to verify like I do the ST’s). The amp obviously works with the TIPs, but if you wanted something more like the originals, which ones to use? The answer is what can you get without risk of fakes, Sanken, Toshiba, ON semi? You can get comparable parts from any of them, if you don’t need the last ounce of speed or ruggedness. Nothing about the original suggests that you do. Would it sound any better? No idea. That really does depend on the amp design - and how much snake (or CBD) oil you’ve been ingesting. Would it measure better? Probably.

georgesgiralt · 17th October 2019, 01:33 PM

;Thank you for your help !
As I plan to use the amplifier for a long time, I've ordered 4 Sanken 2SC4467 / 2SA1694 because I had to order some other parts. These helped get free shipping ...
I'm not listening to my amplifier. I listen to the music. Actually, right now I'm listening to a mono record of an opera ...

Who said that I'm not an audiophile ?

academia50 · 17th October 2019, 09:30 PM

Quote:

Originally Posted by georgesgiralt

....... Actually, right now I'm listening to a mono record of an opera ...

Who said that I'm not an audiophile ?

Maria Callas in its beginnings ?

georgesgiralt · 17th October 2019, 09:59 PM

No,
The marriage of Figaro on an RCA red seal "Selected by the Metropolitan"...

academia50 · 17th October 2019, 11:05 PM

Quote:

Originally Posted by georgesgiralt

No,
The marriage of Figaro on an RCA red seal "Selected by the Metropolitan"...

Very good, it reminds me of the promotions of Selections of the Reader Digest ...... I still have "Popular Music that will live forever" ....... they were monophonic editions of very poor fidelity, but they were promoted with bombastic names ....
But they fulfilled the function of making people know different genres of music.

https://articulo.mercadolibre.com.ar...c-5d510eb1349d

"Cyclophonic" sound! Wow, the sound is insufferable, it does not even come close to the 78 RPM pasta discs, of which I still have some inherited ones, mine were lost and / or broken in successive removals.

I especially remember a 78 RPM pasta album that I listened to until I was tired, it was a pleasant surprise to find those songs on YT:
Giacomo Rondinella, obviously you know him.
Core I´ngrato and Adormendarme Cosí.
Here it is :

YouTube

YouTube

Enjoy and [I]salutti, amicci !

cbdb · 17th October 2019, 11:48 PM

Did you readjust the output transistor bias after replacing them? It probably needs doing, and might make a big difference.

academia50 · 18th October 2019, 05:08 PM

Quote:

Originally Posted by cbdb

Did you readjust the output transistor bias after replacing them? It probably needs doing, and might make a big difference.

If you choose the transistor with the correct gain (Hfe equal to the original) I suppose it will not be necessary.
Note that you must open the circuit to measure the IC current, which is a delicate task on PCBs
Only my two cents

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16th October 2019, 10:26 PM	#11
Enzo diyAudio Member Join Date: Sep 2004 Location: Lansing, Michigan	If you want to buy a few thousand transistors from Toshiba, you can have your name on them, just as Luxman did.

17th October 2019, 12:47 AM	#13
georgesgiralt diyAudio Member Join Date: Jul 2008	"As for replacing 2SD716/2SB686 with TIP and believing nothing has changed...the only conclusion i can draw is you don't really listen to your amps. " I didn't say that. I just said that it works and is about as powerful as it should. As I could not find the correct part (except from ... China .... ) and as I had these, I put them in. But I'm well prepared to put better ones if you can spec them. (and I can find them easily)

17th October 2019, 03:57 AM	#14
wg_ski diyAudio Member Join Date: Oct 2007	Looking at the data sheet I saw nothing special about the original parts, other than they were 60 watt devices. Back in the day they were probably cheaper than the typical 130 to 150 watt TO-3P’s. Any of the typical “audio amp application” TO-3P devices is probably better than the TIPs, which are generic and have very loose specs. They vary greatly from one batch to another. Even amongst real ones (ST uses more than one fab, and you get something different from them that meet the loose spec. ON may do the same, but I don’t have units with different origin codes to verify like I do the ST’s). The amp obviously works with the TIPs, but if you wanted something more like the originals, which ones to use? The answer is what can you get without risk of fakes, Sanken, Toshiba, ON semi? You can get comparable parts from any of them, if you don’t need the last ounce of speed or ruggedness. Nothing about the original suggests that you do. Would it sound any better? No idea. That really does depend on the amp design - and how much snake (or CBD) oil you’ve been ingesting. Would it measure better? Probably.

17th October 2019, 01:33 PM	#15
georgesgiralt diyAudio Member Join Date: Jul 2008	;Thank you for your help ! As I plan to use the amplifier for a long time, I've ordered 4 Sanken 2SC4467 / 2SA1694 because I had to order some other parts. These helped get free shipping ... I'm not listening to my amplifier. I listen to the music. Actually, right now I'm listening to a mono record of an opera ... Who said that I'm not an audiophile ?

17th October 2019, 09:59 PM	#17
georgesgiralt diyAudio Member Join Date: Jul 2008	No, The marriage of Figaro on an RCA red seal "Selected by the Metropolitan"...

17th October 2019, 11:48 PM	#19
cbdb diyAudio Member Join Date: Oct 2008 Location: Vancouver	Did you readjust the output transistor bias after replacing them? It probably needs doing, and might make a big difference.