stage accompany ppa-1200 amp

dud_wity · 30th August 2004, 10:17 PM

hello

i wonder if anyone use or know this amp.
i need its schematic to set the bias correctly..one of the amps warms 3 deg more then the other and i want to fix it.
i will really appreciates any help.
good day
David.

cunningham · 7th September 2004, 10:54 PM

If setting the bias is all, you don't need a scematic. Just turn the bias pot so that the outputs are in cuttoff, then measure the voltage across the emitter resistor, 0.1-0.5Ohms. tweak the pot until you see voltage begen to develope accross the resistor. This is where you want to bias. Disconnect one of the output collectors, and insert an ammeter to be sure.

OliverD · 7th September 2004, 11:56 PM

Quote:

one of the amps warms 3 deg more then the other

Do you think this is a problem? I wouldn't bother to mess with it.

dud_wity · 17th September 2004, 03:09 PM

yes. i think that is the problem.
i didnt see a bias pot thats why i want the schematic..
have a great day!

lumanauw · 2nd June 2008, 07:03 PM

Anyone got a schematic for Stage Accompany power amp? This is an older unit, blue casing, 2 toroid power transformer, has 16 pair of 2SC5200 per channel. Blown up, some resistors are burnt.

nigelwright7557 · 2nd June 2008, 08:43 PM

Quote:

Originally posted by lumanauw
Anyone got a schematic for Stage Accompany power amp? This is an older unit, blue casing, 2 toroid power transformer, has 16 pair of 2SC5200 per channel. Blown up, some resistors are burnt.

I suspect the bias is set using set resistor values after they had a pot in the prototype.

I wouldnt bother for 3 degrees either unless the 3 degrees is 3 degrees above 120 degrees C !

It will be quite a bit of hassle to set the bias plus you might make a mistake and blow the output transistors.

Is it really worth the hassle ?

The last time I set up a bias I blew 6 MOSFETS and it cost me around £15 to replace them.......

lumanauw · 3rd June 2008, 02:00 AM

My problem is different than dud_wity 's (thread starter).

I wanted to repair a blown SA power amp due to overdrive (not the bias problem).

Anybody got SA schematic or service manual?

jacco vermeulen · 3rd June 2008, 06:43 AM

www.sa-vintage.com

lumanauw · 3rd June 2008, 05:04 PM

Thanks, Jacco

Webbie · 5th June 2008, 03:07 PM

Hello David,

The complete PPA 1200 service manual is on his way to me.
I will place it on my site as soon as possible:

www.sa-vintage.com

Also this week on my site:

- Service Manual PPE 2410
- Service Manual Sa 1600/800
- User Manual ES20
- PlexiGlas SA Blue Box foto's from the showroom in Hoorn
- and over 60 scans of SA Product Information

Greetz Webbie...

30th August 2004, 10:17 PM	#1
dud_wity diyAudio Member Join Date: Mar 2004 Location: israel	stage accompany ppa-1200 amp hello i wonder if anyone use or know this amp. i need its schematic to set the bias correctly..one of the amps warms 3 deg more then the other and i want to fix it. i will really appreciates any help. good day David. __________________ when you drink bleach try not to stain your shirt

17th September 2004, 03:09 PM	#4
dud_wity diyAudio Member Join Date: Mar 2004 Location: israel	thank you both yes. i think that is the problem. i didnt see a bias pot thats why i want the schematic.. have a great day! __________________ when you drink bleach try not to stain your shirt

3rd June 2008, 06:43 AM	#8
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, just under Rotterdam	www.sa-vintage.com __________________ Looks like Sponge Bob has killed another thread.

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7th September 2004, 10:54 PM	#2
cunningham diyAudio Member Join Date: Jun 2004 Location: Knoxville	If setting the bias is all, you don't need a scematic. Just turn the bias pot so that the outputs are in cuttoff, then measure the voltage across the emitter resistor, 0.1-0.5Ohms. tweak the pot until you see voltage begen to develope accross the resistor. This is where you want to bias. Disconnect one of the output collectors, and insert an ammeter to be sure.

2nd June 2008, 07:03 PM	#5
lumanauw diyAudio Moderator Emeritus Join Date: Oct 2002 Location: Bandung	Anyone got a schematic for Stage Accompany power amp? This is an older unit, blue casing, 2 toroid power transformer, has 16 pair of 2SC5200 per channel. Blown up, some resistors are burnt.

3rd June 2008, 02:00 AM	#7
lumanauw diyAudio Moderator Emeritus Join Date: Oct 2002 Location: Bandung	My problem is different than dud_wity 's (thread starter). I wanted to repair a blown SA power amp due to overdrive (not the bias problem). Anybody got SA schematic or service manual?

3rd June 2008, 05:04 PM	#9
lumanauw diyAudio Moderator Emeritus Join Date: Oct 2002 Location: Bandung	Thanks, Jacco

5th June 2008, 03:07 PM	#10
Webbie diyAudio Member Join Date: Sep 2007 Location: Wagenberg	Hello David, The complete PPA 1200 service manual is on his way to me. I will place it on my site as soon as possible: www.sa-vintage.com Also this week on my site: - Service Manual PPE 2410 - Service Manual Sa 1600/800 - User Manual ES20 - PlexiGlas SA Blue Box foto's from the showroom in Hoorn - and over 60 scans of SA Product Information Greetz Webbie...

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