Pyramid PB-777

mike49504 · 7th May 2010, 08:23 PM

I recieved this amp in for repair. It has a blown power supply. The are using IRFZ46's for the fets and 100 ohm gate resistors. Wondering if i can swap the fets for something different since i dont have any 46's in stock at the moment. Im ordering alot of parts next week sometime but wanna try to get as many amps done this weekend as i can before i place the order.

mike49504 · 8th May 2010, 03:56 AM

Ok nevermind I found the last 4 that i had in stock

mike49504 · 2nd June 2010, 12:56 AM

I got this amp back and the guy blew the power supply again by clipping the amp.

The fets are IFZZ46's with 100 ohm gates resistors.

Is there a lil bit better fet i can put in this amp?

1moreamp · 2nd June 2010, 01:32 AM

Irfz48 will work and 72 amps rated as i recall, but thats not likely going to stop the guy from killing the power supply.
I am thinking something else is wrong with his install like 16 gauge power wires and poor grounding and etc... the list is endless.. but it sounds like your repairing the symptom, not the problem, IMO......

mike49504 · 2nd June 2010, 02:30 AM

I think you are right. When the amp came back in the gain was turned fully clockwise and the crossover setting was at 450 hz to run the subs.

Id hate to see his wiring job. I played the amp in my truck for 1 hr while driving around and i couldnt kill it he had it for 2 days and it went up in smoke.

Im also repairing another one of his amps and in his truck the amp makes a loud hissing noise something internal but when i hook it up in my truck and pound the heck out of it i get no noise and the amp plays fine.

So your probably 100% right on that one.

Thanks for the info on the fets I greatly appericate it.

7th May 2010, 08:23 PM	#1
mike49504 diyAudio Member Join Date: Sep 2006	Pyramid PB-777 I recieved this amp in for repair. It has a blown power supply. The are using IRFZ46's for the fets and 100 ohm gate resistors. Wondering if i can swap the fets for something different since i dont have any 46's in stock at the moment. Im ordering alot of parts next week sometime but wanna try to get as many amps done this weekend as i can before i place the order.

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
Yamaha PB-1 schematic	Stormrider	Instruments and Amps	11	12th April 2011 10:15 AM
pb with PMA 560	ericb	Solid State	3	2nd August 2008 09:05 AM
Yamaha RX-777	quasi	Solid State	4	15th November 2007 12:58 PM
convert Lead Pb-206 to Pb-205	jacquesl	Everything Else	2	4th February 2007 10:39 AM
Pb / Pb-free	DragonMaster	Everything Else	29	11th January 2006 11:48 AM

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


	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

8th May 2010, 03:56 AM	#2
mike49504 diyAudio Member Join Date: Sep 2006	Ok nevermind I found the last 4 that i had in stock

2nd June 2010, 12:56 AM	#3
mike49504 diyAudio Member Join Date: Sep 2006	I got this amp back and the guy blew the power supply again by clipping the amp. The fets are IFZZ46's with 100 ohm gates resistors. Is there a lil bit better fet i can put in this amp?

2nd June 2010, 01:32 AM	#4
1moreamp diyAudio Member Join Date: Dec 2005 Location: Northern California	Irfz48 will work and 72 amps rated as i recall, but thats not likely going to stop the guy from killing the power supply. I am thinking something else is wrong with his install like 16 gauge power wires and poor grounding and etc... the list is endless.. but it sounds like your repairing the symptom, not the problem, IMO......

2nd June 2010, 02:30 AM	#5
mike49504 diyAudio Member Join Date: Sep 2006	I think you are right. When the amp came back in the gain was turned fully clockwise and the crossover setting was at 450 hz to run the subs. Id hate to see his wiring job. I played the amp in my truck for 1 hr while driving around and i couldnt kill it he had it for 2 days and it went up in smoke. Im also repairing another one of his amps and in his truck the amp makes a loud hissing noise something internal but when i hook it up in my truck and pound the heck out of it i get no noise and the amp plays fine. So your probably 100% right on that one. Thanks for the info on the fets I greatly appericate it.