how do I use this trans?

whatsnext · 9th September 2006, 07:09 PM

I picked up a couple of dead pro amps from a friend that turned out not to be dead but still sound pretty crappy, XP-550 GemSound. I see no point in trying to sell two used amps that that only sell for 179/each new so I was thinking of turning them into something else. The transformer is 53-0-53 at 5A 50/60Hz and can be wired at 220vac to yield 26-0-26 but I think that reduces the output to 250VA. I have about 26000uF of 100V caps per trans. So, can anyone suggest a cool running amp that would use that transformer. I built a DoZ that I really like but don't like the idea of it fighting my AC during the summer. The heatsinks in the 550 are fan cooled and I want to get rid of the fans. There are eight 2SA1943's on each heatsink so it would be handy to use them.
TIA, John

TomWaits · 9th September 2006, 10:01 PM

is a PNP Device and you say they are all the same? No NPN's?

2SA1943

TomWaits · 9th September 2006, 10:03 PM

Just looking at the data sheet 2SA1943 is a nice device? The amp sounds that bad?

Shawn.

whatsnext · 9th September 2006, 10:27 PM

I can only see four of the eight output devices on each heatsink so the bottom ones may be different. I ran the first of the two amps for a couple of days and could not get past the fan noise. When run without the fans it still seemed a little grainy compared to my B&K ST140 or my Hitachi HMA7500 but the heatsinks got warm and I didn't want to risk falling asleep and having it overheat. I've been listening the the second one for a few hours now and it's different. It's smoother sounding, the heatsinks don't seem to get even warm with the fans unplugged, and the power trans is bigger. 60-0-60 6.2A. Weird. Anyway it doesn't really sound bad just not as nice as my other amps unless you plug the fans in in which case the noise drives you out of the room. I'm going to try to series connect the two fans to see if slowing them down quiets them.
John.......

Leolabs · 10th September 2006, 01:17 AM

Quote:

Just looking at the data sheet 2SA1943 is a nice device? The amp sounds that bad?

The 2SA1943/2SC5200 are well known complementary audio output BJT from Toshiba which are widely used by many amp manufacturer.

TomWaits · 10th September 2006, 11:48 PM

Quote:

Originally posted by whatsnext
...I'm going to try to series connect the two fans to see if slowing them down quiets them.
John.......

There are some super quiet fans in the PC market. Spend $20 bucks on a couple from a computer parts store? My 0.02 cents about noisy fans.

Shawn.

9th September 2006, 07:09 PM	#1
whatsnext diyAudio Member Join Date: Mar 2005 Location: KCMO	how do I use this trans? I picked up a couple of dead pro amps from a friend that turned out not to be dead but still sound pretty crappy, XP-550 GemSound. I see no point in trying to sell two used amps that that only sell for 179/each new so I was thinking of turning them into something else. The transformer is 53-0-53 at 5A 50/60Hz and can be wired at 220vac to yield 26-0-26 but I think that reduces the output to 250VA. I have about 26000uF of 100V caps per trans. So, can anyone suggest a cool running amp that would use that transformer. I built a DoZ that I really like but don't like the idea of it fighting my AC during the summer. The heatsinks in the 550 are fan cooled and I want to get rid of the fans. There are eight 2SA1943's on each heatsink so it would be handy to use them. TIA, John

9th September 2006, 10:01 PM	#2
TomWaits diyAudio Member Join Date: Aug 2005	2SA1943's is a PNP Device and you say they are all the same? No NPN's? 2SA1943

9th September 2006, 10:03 PM	#3
TomWaits diyAudio Member Join Date: Aug 2005	2SA1943 Just looking at the data sheet 2SA1943 is a nice device? The amp sounds that bad? Shawn.

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9th September 2006, 10:27 PM	#4
whatsnext diyAudio Member Join Date: Mar 2005 Location: KCMO	I can only see four of the eight output devices on each heatsink so the bottom ones may be different. I ran the first of the two amps for a couple of days and could not get past the fan noise. When run without the fans it still seemed a little grainy compared to my B&K ST140 or my Hitachi HMA7500 but the heatsinks got warm and I didn't want to risk falling asleep and having it overheat. I've been listening the the second one for a few hours now and it's different. It's smoother sounding, the heatsinks don't seem to get even warm with the fans unplugged, and the power trans is bigger. 60-0-60 6.2A. Weird. Anyway it doesn't really sound bad just not as nice as my other amps unless you plug the fans in in which case the noise drives you out of the room. I'm going to try to series connect the two fans to see if slowing them down quiets them. John.......

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