My 66 Fender bassman tube guitar amp is cutting out intermittently and is making a bl

signalpaths · 7th June 2008, 03:00 AM

My 66 Fender bassman tube guitar amp is cutting out intermittently and is making a blip blip blip noise after notes are struck?? Has anyone ever had a similar problem? If so any guidance would be greatly appreciated.

Thanks guys

Eric

DaveMcLain · 7th June 2008, 02:52 PM

blip blip blip sounds like some sort of power supply problem, it's trying to "motorboat". I would bet that the problem is elsewhere and some other portion of the amp is drawing too much current. Look for a bad coupling cap first. It seems like I've had a resistor in the power supply cause that problem before too but it also was caused by some other problem which caused it to see too much current.

signalpaths · 7th June 2008, 03:15 PM

I read somewhere that if a cap has a resistance over 350k that it is leaky is there any truth to this? And if not is there any bulletproof way to test for leakage. BTW I've also heard that if you put AC or DC current through I can't remember what kind or even how much if there is current going through the cap it is leaky. Any help getting to the bottom of this would be appreciated.

Thanks
Eric

audiotuber · 7th June 2008, 04:06 PM

Solder joint, bad connection. Take a chopstick and poke around the board and wires.

audiotuber · 7th June 2008, 04:23 PM

If you want to test for a leaky coupling cap. Put your meter to DC and measure after the coupling cap. There should be very little DC voltage.

signalpaths · 7th June 2008, 08:06 PM

Thank you audiotuber!

signalpaths · 8th June 2008, 04:21 PM

Found it BAD PHASE INVERTER TUBE!!

thanks guys

eric

7th June 2008, 03:00 AM	#1
signalpaths diyAudio Member Join Date: May 2008	My 66 Fender bassman tube guitar amp is cutting out intermittently and is making a bl My 66 Fender bassman tube guitar amp is cutting out intermittently and is making a blip blip blip noise after notes are struck?? Has anyone ever had a similar problem? If so any guidance would be greatly appreciated. Thanks guys Eric

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7th June 2008, 02:52 PM	#2
DaveMcLain diyAudio Member Join Date: Oct 2007	blip blip blip sounds like some sort of power supply problem, it's trying to "motorboat". I would bet that the problem is elsewhere and some other portion of the amp is drawing too much current. Look for a bad coupling cap first. It seems like I've had a resistor in the power supply cause that problem before too but it also was caused by some other problem which caused it to see too much current.

7th June 2008, 03:15 PM	#3
signalpaths diyAudio Member Join Date: May 2008	I read somewhere that if a cap has a resistance over 350k that it is leaky is there any truth to this? And if not is there any bulletproof way to test for leakage. BTW I've also heard that if you put AC or DC current through I can't remember what kind or even how much if there is current going through the cap it is leaky. Any help getting to the bottom of this would be appreciated. Thanks Eric

7th June 2008, 04:06 PM	#4
audiotuber diyAudio Member Join Date: Jun 2008	Solder joint, bad connection. Take a chopstick and poke around the board and wires.

7th June 2008, 04:23 PM	#5
audiotuber diyAudio Member Join Date: Jun 2008	If you want to test for a leaky coupling cap. Put your meter to DC and measure after the coupling cap. There should be very little DC voltage.

7th June 2008, 08:06 PM	#6
signalpaths diyAudio Member Join Date: May 2008	Thank you audiotuber!

8th June 2008, 04:21 PM	#7
signalpaths diyAudio Member Join Date: May 2008	Found it BAD PHASE INVERTER TUBE!! thanks guys eric