Did anyone recognise that schematic?

astankov · 9th February 2011, 06:26 AM

A friend of mine give me that schematic and he told me that is been used in a commercial product as power stage amp but he don't want to tell me the brand and the model of that product. As you can see it is an old design maybe from 80's with many drawbacks but i wan't to know in what is been used.

There are two pictures - one from original paper drawing and one more readable and clear produced by me.

So if someone knows something please reply. Thanks to the people who will answer.

Nico Ras · 9th February 2011, 02:50 PM

Could be any of several hundred commercial amps of the late sixties even early seventies era but the design may still be used in many amps of today.

Why is it important who made it? Brand name does not make it any better or worse.

astankov · 9th February 2011, 04:21 PM

Quote:

Originally Posted by Nico Ras

Could be any of several hundred commercial amps of the late sixties even early seventies era but the design may still be used in many amps of today.

Why is it important who made it? Brand name does not make it any better or worse.

My frend was very persistent not to tell me and I'm just wondering why is that. Thats why I'm asking - to solve the mistery. I know that is not good to use today there are much better designs but I dont care.

So if someone knows something please comment. Thanks.

Bigun · 04:41 PM

Maybe if he's your friend and he was persistent you don't want to offend him by trying to find out here.

It has many issues, e.g. no rail decoupling on the zener at the front end, don't like them diodes on the VAS base either and the Vbe multiplier will blow up the amp if the potentiometer fails.

MJL21193 · 9th February 2011, 04:52 PM

Quote:

Originally Posted by Bigun

don't like them diodes on the VAS base either .

Clamping...

Bigun · 9th February 2011, 05:24 PM

and they won't conduct at normal levels, not at all ?

MJL21193 · 9th February 2011, 05:32 PM

Conduct what? DC?

astankov · 9th February 2011, 06:44 PM

No problem! Most of bulgarians including my friend dont understand english at all and they even dont know about the existence of this forum so there is no problem. I dont see how I will offend him.

I know that schematic is bad to use and I dont want comments about it.
Only needed comment is where is been used.
But if no one recognize it also no problem.

MJL21193 · 9th February 2011, 06:53 PM

Quote:

Originally Posted by astankov

I know that schematic is bad to use and I dont want comments about it.
.

You know it's bad? You don't want comments about it?

It isn't really any worse than most of the amps seen here, and perhaps quite a bit better than some.

astankov · 9th February 2011, 07:05 PM

Better than what? Any worse examlpes?
By say bad I mean how it sounds - not very well compared to others more up to date designs thats it. But if you build it will work well without a problem. I build it and just dont like how it sounds.

9th February 2011, 04:39 PM	#4
Bigun diyAudio Member Join Date: Jan 2009 Location: K-W Ontario Blog Entries: 2	Maybe if he's your friend and he was persistent you don't want to offend him by trying to find out here. It has many issues, e.g. no rail decoupling on the zener at the front end, don't like them diodes on the VAS base either and the Vbe multiplier will blow up the amp if the potentiometer fails. __________________ "The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig. Last edited by Bigun; 9th February 2011 at 04:41 PM.

9th February 2011, 05:24 PM	#6
Bigun diyAudio Member Join Date: Jan 2009 Location: K-W Ontario Blog Entries: 2	and they won't conduct at normal levels, not at all ? __________________ "The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.

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9th February 2011, 02:50 PM	#2
Nico Ras diyAudio Member Join Date: Nov 2005 Location: Amanzimtoti - East Coast of South Africa	Could be any of several hundred commercial amps of the late sixties even early seventies era but the design may still be used in many amps of today. Why is it important who made it? Brand name does not make it any better or worse.

9th February 2011, 05:32 PM	#7
MJL21193 Account disabled at member's request Join Date: Mar 2007	Conduct what? DC?

9th February 2011, 06:44 PM	#8
astankov diyAudio Member Join Date: Dec 2009 Location: Pernik	No problem! Most of bulgarians including my friend dont understand english at all and they even dont know about the existence of this forum so there is no problem. I dont see how I will offend him. I know that schematic is bad to use and I dont want comments about it. Only needed comment is where is been used. But if no one recognize it also no problem.

9th February 2011, 07:05 PM	#10
astankov diyAudio Member Join Date: Dec 2009 Location: Pernik	Better than what? Any worse examlpes? By say bad I mean how it sounds - not very well compared to others more up to date designs thats it. But if you build it will work well without a problem. I build it and just dont like how it sounds.

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