too long strat 'clip'

[mat]

Hi

Here is my nonHRM with diy strat miced from 2 inches from RWB with sm57 while my dog jumping on me all the time . No processing (reverb is from the amp). I only have the neck and middle pu's on my strat. It sounds best with the bridge pu, but I kind of like all positions..

The amp did sing nicely with harmonics but when recording I did not got it to sing no more Maybe it noticed I was using strat instead a hb guitar (or it was the position where I was sitting)

The playing is not to listen for, only the sound please

I still have nasty noise problem on the od channel. I still have carbon composites on the cathodes, have to swap the to metal films for sure.

So here it is: http://media.putfile.com/umblestrat

[Bob-I]

Sounds good, nice and smooth. Too bad about the hum. Sounds like a grounding issue to me.

[mat]

Sounds good, nice and smooth. Too bad about the hum. Sounds like a grounding issue to me.

Thanks Bob-I. I have tried to figure out what is it with the noise problem.

I have checked the groundings and they seem fine to me at least (that is not saying there can't be a problem).

First took out PI-tube. Noise went away.

Then took away OD tube. Again noise went away.

Took out CL tube. Noise went away.

Then I did put a .01/600V cap on a stick with other end grounded and touched CL1 pin 2 - slight improvement.

CL2 pin 7 - the noise went away almost complitely.

OD1 pin2 - no noise at all.

OD2 pin7 - no noise at all.

When the noise went away the signal also went away. I could only hear very faint guitar sound when strumming.

I took of the local FBL but no improvement.

Could it be my power tubes ? I have seperate biaspots and the other tube wont go hotter than -50mV(A), the other goes to -40mV(A) on identical pot/resistor.

I also measured the AC voltage across the 100ohms on the heater taps. They were different.

Guitars volume makes the noise worse but it is still there eaven the guitar unplugged. Pre volume makes the noise slightly worse. Master volume makes the noise worse big time. Also drive pot makes it really bad.

Any help much appreciated.

[Bob-I]

Sounds good, nice and smooth. Too bad about the hum. Sounds like a grounding issue to me.

Thanks Bob-I. I have tried to figure out what is it with the noise problem.

I have checked the groundings and they seem fine to me at least (that is not saying there can't be a problem).

First took out PI-tube. Noise went away.

Then took away OD tube. Again noise went away.

Took out CL tube. Noise went away.

This would appear to indicate that the noise is in the CL stages.

Then I did put a .01/600V cap on a stick with other end grounded and touched CL1 pin 2 - slight improvement.

CL2 pin 7 - the noise went away almost complitely.

OD1 pin2 - no noise at all.

OD2 pin7 - no noise at all.

When the noise went away the signal also went away. I could only hear very faint guitar sound when strumming.

I'm not sure what you're getting at with this testing.

I took of the local FBL but no improvement.

Could it be my power tubes ? I have seperate biaspots and the other tube wont go hotter than -50mV(A), the other goes to -40mV(A) on identical pot/resistor.

Not likely since the noise goes away without the PI tube.

I also measured the AC voltage across the 100ohms on the heater taps. They were different.

Maybe, but again not likely.

Guitars volume makes the noise worse but it is still there eaven the guitar unplugged. Pre volume makes the noise slightly worse. Master volume makes the noise worse big time. Also drive pot makes it really bad.

Any help much appreciated.

More evidence that the CL tube is the problem.

Before you continue to drive yourself crazy try...

1) A new tube in V1
2) If you used stranded wire for the heaters, look carefully under magnification for any strands that are loose. I've seen 2 cases of heater strands touching other pins injecting noise.
3) If 1 and 2 don't work you might want to listen to each stage on it's own to narrow it down.

I built a test connector for this. Using a female 1/4" jack I soldered in an aligator clip to the ground, then a .1uF cap to the hot and an aligator clip to the other side of the cap.

Power up the amp and connect the 1/4" to another amp, I use my stereo. Ground the ground wire to the chassis, then use the aligator clip to the cap to listen to the various stages. Start by connecting right to the input jack, listen for the hum, Connect to the plate of V1a (this is why you need the cap, to block DC) and listen.

Once you find which stage is making the hum, you can troubleshoot. Look for faulty components, cold solder joints, poor grounding schemes etc. I've found a lot of problems using this method.

Good luck.

[mat]

I have checked the groundings and they seem fine to me at least (that is not saying there can't be a problem).

First took out PI-tube. Noise went away.

Then took away OD tube. Again noise went away.

Took out CL tube. Noise went away.

This would appear to indicate that the noise is in the CL stages.[/quote]

When PAB off and OD off there is no noise. With PAB on and OD off it is still quite clean (no noise). But when engaging OD with or without PAB the noise jumps out

Then I did put a .01/600V cap on a stick with other end grounded and touched CL1 pin 2 - slight improvement.

CL2 pin 7 - the noise went away almost complitely.

OD1 pin2 - no noise at all.

OD2 pin7 - no noise at all.

When the noise went away the signal also went away. I could only hear very faint guitar sound when strumming.

I'm not sure what you're getting at with this testing.

To be honest, neither do I I just read from the forum to check where the noise problem might with that technique.

I took of the local FBL but no improvement.

Could it be my power tubes ? I have seperate biaspots and the other tube wont go hotter than -50mV(A), the other goes to -40mV(A) on identical pot/resistor.

Not likely since the noise goes away without the PI tube.

Ok.

I also measured the AC voltage across the 100ohms on the heater taps. They were different.

Maybe, but again not likely.

Guitars volume makes the noise worse but it is still there eaven the guitar unplugged. Pre volume makes the noise slightly worse. Master volume makes the noise worse big time. Also drive pot makes it really bad.

Any help much appreciated.

More evidence that the CL tube is the problem.

Before you continue to drive yourself crazy try...

1) A new tube in V1

That I have tried, no fix.

2) If you used stranded wire for the heaters, look carefully under magnification for any strands that are loose. I've seen 2 cases of heater strands touching other pins injecting noise.

I used solidcore wire, will check them anyway.

3) If 1 and 2 don't work you might want to listen to each stage on it's own to narrow it down.

I built a test connector for this. Using a female 1/4" jack I soldered in an aligator clip to the ground, then a .1uF cap to the hot and an aligator clip to the other side of the cap.

Power up the amp and connect the 1/4" to another amp, I use my stereo. Ground the ground wire to the chassis, then use the aligator clip to the cap to listen to the various stages. Start by connecting right to the input jack, listen for the hum, Connect to the plate of V1a (this is why you need the cap, to block DC) and listen.

Once you find which stage is making the hum, you can troubleshoot. Look for faulty components, cold solder joints, poor grounding schemes etc. I've found a lot of problems using this method.

Good luck.

[/quote]

Thanks Bob-I, I will try this method and report the findings

[keithrick]

Mat, nice clip any luck with the hum?

You have built a kick ass amp so don't take this as an insult to your skills.

Have you tried to move the amp (or yourself) around? Sometimes the easist solution is the right in front of you...so are you sure that you are not just sitting to close to your amp? If I get to close (within 3feet) my amp will pick up hum. I hope you find the hum! Good luck.

[mat]

Hi Keithrick

Mat, nice clip any luck with the hum?

You have built a kick ass amp so don't take this as an insult to your skills.

Have you tried to move the amp (or yourself) around? Sometimes the easist solution is the right in front of you...so are you sure that you are not just sitting to close to your amp? If I get to close (within 3feet) my amp will pick up hum. I hope you find the hum! Good luck.

Keithrick, I consider myself still very much as a beginner. I don't get insulted - I'm very greatful for every piece of information/suggestion I get here

Yes, I've tried moving further from the amp + I've played it on my son's room when jamming with him - same noise.

I will try the Bob-I's suggestion as soon as possible (busy at work.. after couple of days I hope I'll be viser).

Thanks,

[Bob-I]

When PAB off and OD off there is no noise. With PAB on and OD off it is still quite clean (no noise). But when engaging OD with or without PAB the noise jumps out

Ahh... important information. I'd bet it's relay supply noise. I'd try disconnecting the relay power supply, then use a battery to activate the relay. If the noise is gone you have your source.

[mat]

When PAB off and OD off there is no noise. With PAB on and OD off it is still quite clean (no noise). But when engaging OD with or without PAB the noise jumps out

Ahh... important information. I'd bet it's relay supply noise. I'd try disconnecting the relay power supply, then use a battery to activate the relay. If the noise is gone you have your source.

Thanks Bob, Ill try this asap.
cheers,

[mat]

Did not have a chance to open my clone yet but here is a (too long) clip with the really cheap Epiphone Les Paul with a diy humbucker. Master was at 1,5. It started to sing quite nicely. The noise problem can be heard also very clearly in there. The playing is just to listen to the amp, nothing musical in there

Little bit of delay added to the mix (reverb is from the amp).

http://media.putfile.com/nonHRMepipaul

[mat]

Hello Bob-I,

I disconnected the wires from heaters to the diodebridge and the noise went away. The relays still stayed on the PAB-on and OD-on position. I tried to redirect the wires more properly but as soon as I connect the 6,3V to the diodebridge, the noise comes in

Any suggestions ?

Thank You,

[heisthl]

Try isolating or unisolating the grounds assocoated with the relays (footswitchjack,bridge,caps etc). If that doesn't work you may find relief with larger filtering on the relay supply. If all else fails use a separate transformer for the relays (wall warts work good and are only 2 or 3 bucks at a thrift store, try to find one with screws so you can take it apart and hardwire the 120V).

[mat]

Try isolating or unisolating the grounds assocoated with the relays (footswitchjack,bridge,caps etc). If that doesn't work you may find relief with larger filtering on the relay supply. If all else fails use a separate transformer for the relays (wall warts work good and are only 2 or 3 bucks at a thrift store, try to find one with screws so you can take it apart and hardwire the 120V).

I have two 1000uF in parallel on the relay supply + 0.1uF in series to the ground. I'll try to skip the 0.1uF if it helps and put another 1000uF in to see if that helps. If not I'll check suitable tranny.

Thanks for the tips!

[heisthl]

I should be looking at your schematic - a single 1000uF is more than adequate, not sure what you're trying to accomplish with the .01.

[mat]

I should be looking at your schematic - a single 1000uF is more than adequate, not sure what you're trying to accomplish with the .01.

I was told as: 'You need to "float" the bridge - terminal thru a .1 or so poly cap to ground. If you don't do this you're going to get AC hum. '