ADS PQ20

mike49504 · 22nd April 2011, 04:00 PM

Im starting a new thread on this amp since the last thread says it was closed.

I got the amp to power up and stay powerd up now the amp had a blown trace on the output board.

The amp plays But there are a couple of problems.

1ST problem: when listing to the amp it sounds like the music has an echo to it.

2ND problem: I can hear a hum through all speakers connected to the amp with and without volume.

Any ideas?

Perry Babin · 22nd April 2011, 04:05 PM

Does it hum with no RCAs connected?

Is the signal source ground tied to the amp ground?

mike49504 · 22nd April 2011, 06:37 PM

It hums with no rca's plugged in.

Signal source ground Do you mean the rca shields?

Perry Babin · 22nd April 2011, 08:28 PM

Yes if it's a portable player. If it's a head unit, the ground for the head unit would be the signal source ground.

mike49504 · 10th May 2011, 04:16 AM

Ok back to this amp.Im going throught the entire amp top to bottom to get it to sound like brand new again.

Not sure what year this amp was made but wondering if it is a good idea to replace the caps in this amp due to age. If so wondering who makes the best caps out there? When i get this amp done i want it to be pure sound quality

seankane · 10th May 2011, 04:24 AM

Nichicon Muse are very nice caps to use.

mike49504 · 10th May 2011, 04:37 AM

Cool thanks. Still wondering if there is a even better brand out there? I wanna rebuild this amp from the bottom up. Im looking to get the best sound out of it as possible

mike49504 · 10th May 2011, 04:44 AM

Wondering If anyone has opinions on the Panasonic FC series caps?

Perry Babin · 10th May 2011, 02:55 PM

FC series caps are a good choice for power supplies. They can take more abuse than many capacitors. In this amp, there aren't any capacitors that will be under any real stress. Virtually any capacitor within spec will work. Assuming that all caps meet spec, using expensive capacitors or cheap capacitors won't make a difference in the sound quality.

mike49504 · 18th May 2011, 03:58 AM

Im working on this amp still while waiting for parts for other amps.

Im almost done rebuilding the power supply section of this amp then its off to the output section.

My question is if 1 of the UPC1270H's are bad in this amp would that cause the humming through the speakers or cause the music to echo??

22nd April 2011, 04:00 PM	#1
mike49504 diyAudio Member Join Date: Sep 2006	ADS PQ20 Im starting a new thread on this amp since the last thread says it was closed. I got the amp to power up and stay powerd up now the amp had a blown trace on the output board. The amp plays But there are a couple of problems. 1ST problem: when listing to the amp it sounds like the music has an echo to it. 2ND problem: I can hear a hum through all speakers connected to the amp with and without volume. Any ideas?

22nd April 2011, 04:05 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Does it hum with no RCAs connected? Is the signal source ground tied to the amp ground? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

22nd April 2011, 08:28 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Yes if it's a portable player. If it's a head unit, the ground for the head unit would be the signal source ground. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

10th May 2011, 04:24 AM	#6
seankane diyAudio Member Join Date: May 2010 Location: Washington State	Nichicon Muse are very nice caps to use. __________________ Pyramid 46 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch

10th May 2011, 02:55 PM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	FC series caps are a good choice for power supplies. They can take more abuse than many capacitors. In this amp, there aren't any capacitors that will be under any real stress. Virtually any capacitor within spec will work. Assuming that all caps meet spec, using expensive capacitors or cheap capacitors won't make a difference in the sound quality. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


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22nd April 2011, 06:37 PM	#3
mike49504 diyAudio Member Join Date: Sep 2006	It hums with no rca's plugged in. Signal source ground Do you mean the rca shields?

10th May 2011, 04:16 AM	#5
mike49504 diyAudio Member Join Date: Sep 2006	Ok back to this amp.Im going throught the entire amp top to bottom to get it to sound like brand new again. Not sure what year this amp was made but wondering if it is a good idea to replace the caps in this amp due to age. If so wondering who makes the best caps out there? When i get this amp done i want it to be pure sound quality

10th May 2011, 04:37 AM	#7
mike49504 diyAudio Member Join Date: Sep 2006	Cool thanks. Still wondering if there is a even better brand out there? I wanna rebuild this amp from the bottom up. Im looking to get the best sound out of it as possible

10th May 2011, 04:44 AM	#8
mike49504 diyAudio Member Join Date: Sep 2006	Wondering If anyone has opinions on the Panasonic FC series caps?

18th May 2011, 03:58 AM	#10
mike49504 diyAudio Member Join Date: Sep 2006	Im working on this amp still while waiting for parts for other amps. Im almost done rebuilding the power supply section of this amp then its off to the output section. My question is if 1 of the UPC1270H's are bad in this amp would that cause the humming through the speakers or cause the music to echo??

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