amp circuit help

scott3292 · 9th July 2005, 07:49 PM

Hi

I have 6 of these amps (schematic attached.) taken out of a hospital and am trying to hook them up to my Yamaha reciever for an awesome looking home theater system but can't figure out what to do to get them to work. They worked in the hospital but I don't know enough about circuits to figure them out. I know I have to remove the step-up tranformer as it generates 70 volts, but what eles do I have to do. Audio in on the N1 & C terminals, out before T1 but the amps don't seem to turn on ( power is on). Ideas????

Thanks for reading.

Scott

johnnyx · 9th July 2005, 07:52 PM

What schematic?

djk · 10th July 2005, 12:55 AM

Don't bother trying to hook them up (sorry).

anatech · 10th July 2005, 12:51 PM

Hi Scott,
Djk is right, they look like they will sound nasty (as in horrible).

You did get free chassis and transformers plus whatever else is useable. Why not build a DIY amp project? Build one and once it's going, build the rest. You are correct that the 70V line transformers must go.

-Chris

Eva · 10th July 2005, 10:14 PM

Altough this schematic that you have posted is almost unreadable, it's quite easy to identify a push-pull topology in it.

In other words: These amplifiers won't work without output transformers.

sam9 · 10th July 2005, 11:39 PM

Awsome looking, maybe, but not awsome sounding. Not being snobbish. These look like on old PA system. The output transformer is a giveaway. They will probably sound like a PA system. Maybe not a bad as listening to music over the telephone. . .

scott3292 · 11th July 2005, 06:53 AM

thanks for the ideas , I will look into making the amps. The rack with 6 of these amps in it look real cool.

sam9 · 11th July 2005, 01:58 PM

You can still use the enclosures, just putt beeter stuff in them. Saves a lot of money, too. It may even be possible to salvage the transformers and other power supply parts.

scott3292 · 11th July 2005, 08:59 PM

A neat idea but would the final result be any better than just using the Yamaha? Right now I have it powering 6 mission bookshelf speakers & 2 100 watt subs, plus a Harman Karden (200 watt) powering 6 AR satelites speakers and a 100 watt sub. The goal is to use all the speakers but only one source as with two, the sound seperation gets a little blended. This is in a large rec room mainly for movies. As you can imagine I like a full sounding system.
Thanks Scott

anatech · 11th July 2005, 09:32 PM

Hi Scott,
I like Yamaha and fixed them under warranty for years. You can do better with the external amps. Yamaha make really good processors. They do not make really robust amplifiers. Not in receivers anyway.

-Chris

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9th July 2005, 07:52 PM	#2
johnnyx diyAudio Member Join Date: Jan 2004 Location: manchester	What schematic?

10th July 2005, 12:55 AM	#3
djk diyAudio Member Join Date: Feb 2001 Location: USA	Don't bother trying to hook them up (sorry).

10th July 2005, 12:51 PM	#4
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Scott, Djk is right, they look like they will sound nasty (as in horrible). You did get free chassis and transformers plus whatever else is useable. Why not build a DIY amp project? Build one and once it's going, build the rest. You are correct that the 70V line transformers must go. -Chris

10th July 2005, 10:14 PM	#5
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	Altough this schematic that you have posted is almost unreadable, it's quite easy to identify a push-pull topology in it. In other words: These amplifiers won't work without output transformers.

10th July 2005, 11:39 PM	#6
sam9 diyAudio Member Join Date: Jun 2002 Location: Left Coast	Awsome looking, maybe, but not awsome sounding. Not being snobbish. These look like on old PA system. The output transformer is a giveaway. They will probably sound like a PA system. Maybe not a bad as listening to music over the telephone. . .

11th July 2005, 06:53 AM	#7
scott3292 diyAudio Member Join Date: Jul 2005 Location: Peterborough, Ontario	thanks for the ideas , I will look into making the amps. The rack with 6 of these amps in it look real cool.

11th July 2005, 01:58 PM	#8
sam9 diyAudio Member Join Date: Jun 2002 Location: Left Coast	You can still use the enclosures, just putt beeter stuff in them. Saves a lot of money, too. It may even be possible to salvage the transformers and other power supply parts.

11th July 2005, 08:59 PM	#9
scott3292 diyAudio Member Join Date: Jul 2005 Location: Peterborough, Ontario	A neat idea but would the final result be any better than just using the Yamaha? Right now I have it powering 6 mission bookshelf speakers & 2 100 watt subs, plus a Harman Karden (200 watt) powering 6 AR satelites speakers and a 100 watt sub. The goal is to use all the speakers but only one source as with two, the sound seperation gets a little blended. This is in a large rec room mainly for movies. As you can imagine I like a full sounding system. Thanks Scott

11th July 2005, 09:32 PM	#10
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Scott, I like Yamaha and fixed them under warranty for years. You can do better with the external amps. Yamaha make really good processors. They do not make really robust amplifiers. Not in receivers anyway. -Chris

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