Elliot P33 problem

PM650 · 19th December 2005, 05:04 AM

I've built two p33's with my own boards and they're both experiencing the same problem. The turn on delay is working fine, but the dc protection part is causing the relay to stay off. Here are the voltages I measured:

I've checked both boards numerous times and they are correct.
Any ideas?

Also, I'm having some problems with relay chatter; two relays are being run off each p33, in parallel, each with their own protection diodes but the one of the two for the speaker uses the config. shown on the site with a regular diode and a zener back to back, while the second uses just a regular diode. Could this be solved by connecting the relays in series with the clamp diodes around both?

lineup · 19th December 2005, 11:11 AM

1.25 V is a strange value
I would expect more like 0 V

But this does not explain why relays stay OFF.

When feeding both relays in parallell,
make sure you use a bigger transistor for drive them
TO126 (or TO220)

a normal TO92 small signal is not enough

dx.master · 19th December 2005, 12:23 PM

Hello !

Did you link IN-R and IN-L to GND ?
You must set both channels to the right value.

I build also 2 pc of PCB with this circuit and it work very well afer changing some Resitors!

PM650 · 19th December 2005, 11:54 PM

lineup: I am using the standard mpsa92 recomended on the site and have not experienced any problems. Total current drawn by both relays and the resistor is 78mA.

dx.master: I'm not exactly sure what your saying. My speaker grounds return to the central earth point formed by the filter caps on the pcb.

I am only using one p33 per amp, so R2, C2, D1 and D2 are not included in my circuit. Each of my p33's are integrated onto the same pcb as the bridge and filter caps for the amps; is it possible that excess ripple is being injected into the circuit? Some of the taps for the rails are taken between the bridge and caps on the +/- planes.

I can post the board layout if this will help solve any confusion.

dx.master · 20th December 2005, 09:09 AM

please make some photos of your PCB board and show it us.

Thanks.

PM650 · 20th December 2005, 09:49 AM

Here's the top view of the copper:

(the second relay is on a different board)
It may be a bit difficult to follow because this was my first board I've designed. I'm planing to remake these with better material boards (FR4) and I would like the next pair to actually work, so any ideas are appreciated.

19th December 2005, 05:04 AM	#1
PM650 diyAudio Member Join Date: Jul 2005 Location: Tennessee	Elliot P33 problem I've built two p33's with my own boards and they're both experiencing the same problem. The turn on delay is working fine, but the dc protection part is causing the relay to stay off. Here are the voltages I measured: I've checked both boards numerous times and they are correct. Any ideas? Also, I'm having some problems with relay chatter; two relays are being run off each p33, in parallel, each with their own protection diodes but the one of the two for the speaker uses the config. shown on the site with a regular diode and a zener back to back, while the second uses just a regular diode. Could this be solved by connecting the relays in series with the clamp diodes around both?

19th December 2005, 12:23 PM	#3
dx.master diyAudio Member Join Date: Jul 2004 Location: Hessen, Germany	IN-R and IN-L to GND Hello ! Did you link IN-R and IN-L to GND ? You must set both channels to the right value. I build also 2 pc of PCB with this circuit and it work very well afer changing some Resitors!

20th December 2005, 09:09 AM	#5
dx.master diyAudio Member Join Date: Jul 2004 Location: Hessen, Germany	please make some photos please make some photos of your PCB board and show it us. Thanks.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Rod Elliot P37?	roger-k	Solid State	21	7th October 2006 07:37 PM
Trace Elliot GP12SMX Bass Preamp Hum Problem	DigitalDon	Instruments and Amps	7	28th May 2005 05:02 AM
Rod Elliot P06 Riaa problem	gchrist	Solid State	32	24th September 2004 03:14 PM
Elliot's 60W AB amp	mrpibb	Solid State	2	29th April 2001 09:51 PM


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

19th December 2005, 11:11 AM	#2
lineup diyAudio Member Join Date: Dec 2005 Location: the north	1.25 V is a strange value I would expect more like 0 V But this does not explain why relays stay OFF. When feeding both relays in parallell, make sure you use a bigger transistor for drive them TO126 (or TO220) a normal TO92 small signal is not enough

19th December 2005, 11:54 PM	#4
PM650 diyAudio Member Join Date: Jul 2005 Location: Tennessee	lineup: I am using the standard mpsa92 recomended on the site and have not experienced any problems. Total current drawn by both relays and the resistor is 78mA. dx.master: I'm not exactly sure what your saying. My speaker grounds return to the central earth point formed by the filter caps on the pcb. I am only using one p33 per amp, so R2, C2, D1 and D2 are not included in my circuit. Each of my p33's are integrated onto the same pcb as the bridge and filter caps for the amps; is it possible that excess ripple is being injected into the circuit? Some of the taps for the rails are taken between the bridge and caps on the +/- planes. I can post the board layout if this will help solve any confusion.

20th December 2005, 09:49 AM	#6
PM650 diyAudio Member Join Date: Jul 2005 Location: Tennessee	Here's the top view of the copper: (the second relay is on a different board) It may be a bit difficult to follow because this was my first board I've designed. I'm planing to remake these with better material boards (FR4) and I would like the next pair to actually work, so any ideas are appreciated.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read