....

[screamindemon]

If I have a mustard cap that reads 22000 could you please tell me the value ?

Thanks so much for all your help !

 

[screamindemon]

Awesome thanks !

 

[screamindemon]

OK, so I made all the changes except the following.

1.Still need to change the phase inverter coupling caps from .1uf to .022 uf. (on order)

2.Change the inverter cap from 47pf to 56pf.

3.Change the big spit cap at center of board from 33uf+33uf to a 50uf+50uf. not sure of the name of this one ?

4.change V1A cathode cap from 250uf to 330uf. (on order)

5. Change presence pot to 25k and use 4.7k resister.

At this point is it worth firing it up and giving her a test drive?

 

[screamindemon]

OK, sounds good !

here is what it looks like right now !

 

[screamindemon]

So, I fired it up last night and I may have a problem.
I put a new set of matched EL 34s in it and hooked up my Bias right and was getting about 450 volts per plate then switched to cathode current and reading went to zero.

My have a problem with the Bias rite, put in new battery no change.
going to test it out on one of my other amps today and try and figure out whats going on.

Hopefully I didn't mess anything up, but I think everything is right.

 

[sjk]

So, I fired it up last night and I may have a problem.
I put a new set of matched EL 34s in it and hooked up my Bias right and was getting about 450 volts per plate then switched to cathode current and reading went to zero.

My have a problem with the Bias rite, put in new battery no change.
going to test it out on one of my other amps today and try and figure out whats going on.

Hopefully I didn't mess anything up, but I think everything is right.

I had a weber bias right that worked great for about 3,4 years and then stopped giving good readings and started doing funky stuff. If you have a multimeter you could read bias by putting black probe to chassis and then the red probe to the 1 watt resistor soldered between ground and cathode pin on each tube socket. That is how I do it now and it seems a little more accurate then bias meters and such. It is more dangerous so you have to be more careful obviously.

 

[screamindemon]

So, I fired it up last night and I may have a problem.
I put a new set of matched EL 34s in it and hooked up my Bias right and was getting about 450 volts per plate then switched to cathode current and reading went to zero.

My have a problem with the Bias rite, put in new battery no change.
going to test it out on one of my other amps today and try and figure out whats going on.

Hopefully I didn't mess anything up, but I think everything is right.

I had a weber bias right that worked great for about 3,4 years and then stopped giving good readings and started doing funky stuff. If you have a multimeter you could read bias by putting black probe to chassis and then the red probe to the 1 watt resistor soldered between ground and cathode pin on each tube socket. That is how I do it now and it seems a little more accurate then bias meters and such. It is more dangerous so you have to be more careful obviously.

Thanks for the info but I'm not sure which pin that is ?

 

[sjk]

So, I fired it up last night and I may have a problem.
I put a new set of matched EL 34s in it and hooked up my Bias right and was getting about 450 volts per plate then switched to cathode current and reading went to zero.

My have a problem with the Bias rite, put in new battery no change.
going to test it out on one of my other amps today and try and figure out whats going on.

Hopefully I didn't mess anything up, but I think everything is right.

I had a weber bias right that worked great for about 3,4 years and then stopped giving good readings and started doing funky stuff. If you have a multimeter you could read bias by putting black probe to chassis and then the red probe to the 1 watt resistor soldered between ground and cathode pin on each tube socket. That is how I do it now and it seems a little more accurate then bias meters and such. It is more dangerous so you have to be more careful obviously.

Thanks for the info but I'm not sure which pin that is ?

This page here shows it and can explain it better than me, I'm no amp tech just do a little soldering and amp biasing Scroll down a bit and it shows a tube socket diagram.
https://robrobinette.com/Tube_Bias_Calculator.htm

 

[screamindemon]

So, I fired it up last night and I may have a problem.
I put a new set of matched EL 34s in it and hooked up my Bias right and was getting about 450 volts per plate then switched to cathode current and reading went to zero.

My have a problem with the Bias rite, put in new battery no change.
going to test it out on one of my other amps today and try and figure out whats going on.

Hopefully I didn't mess anything up, but I think everything is right.

I had a weber bias right that worked great for about 3,4 years and then stopped giving good readings and started doing funky stuff. If you have a multimeter you could read bias by putting black probe to chassis and then the red probe to the 1 watt resistor soldered between ground and cathode pin on each tube socket. That is how I do it now and it seems a little more accurate then bias meters and such. It is more dangerous so you have to be more careful obviously.

Thanks for the info but I'm not sure which pin that is ?

This page here shows it and can explain it better than me, I'm no amp tech just do a little soldering and amp biasing Scroll down a bit and it shows a tube socket diagram.
https://robrobinette.com/Tube_Bias_Calculator.htm

Thanks for the info ! I will check it out.

Looks like my Bias rite took a dump ! I hooked it up to my plexi and got the same messed up readings.

 

[codyjarret]

I see some possible problems.
I marked in what the values should be.

 

[screamindemon]

I see some possible problems.
I marked in what the values should be.

I think those value are correct, I will double check.

That is if I am reading these cap values correct !

 

[codyjarret]

I see some possible problems.
I marked in what the values should be.

I think those value are correct, I will double check.

That is if I am reading these cap values correct !

They might be right but I'm just making sure.
I can't make-out the values from the picture.

 

[screamindemon]

I see some possible problems.
I marked in what the values should be.

I think those value are correct, I will double check.

That is if I am reading these cap values correct !

Yes sir, you are correct I had the plate bypass caps crossed.

I am finally understanding how to read these things ! LOL

 

[screamindemon]

OK, I think everything is in order now ! Now if I can figure out how to Bias this thing without my Bias rite.

Just waiting on the .022 phase inverter coupling caps and we should be close !

 

[screamindemon]

I fired it up just for a minute just to see and works but doesn't seem to have alot of gain.
When I turn both gains up it gets the we-yous ! LOL

Sounds like a cocked wah.

Still need to bias it, and make the other changes.

 

[screamindemon]

I am going to order a new bias meter next week.
I was reading where you can take a 1ohm 1 watt resister from pin 8 to ground and take your cathode current reading there.

I see a resister soldered between pin 1 and 8 on my power tubes sockets, could this be the same as the resister to ground ? Or is this for something else?

Thanks

 

[sjk]

I am going to order a new bias meter next week.
I was reading where you can take a 1ohm 1 watt resister from pin 8 to ground and take your cathode current reading there.

I see a resister soldered between pin 1 and 8 on my power tubes sockets, could this be the same as the resister to ground ? Or is this for something else?

Thanks

Thats it the one to make the reading on your powertube socket. I don't know a whole lot about amps but I do recognize that fwiw.

 

[screamindemon]

I am going to order a new bias meter next week.
I was reading where you can take a 1ohm 1 watt resister from pin 8 to ground and take your cathode current reading there.

I see a resister soldered between pin 1 and 8 on my power tubes sockets, could this be the same as the resister to ground ? Or is this for something else?

Thanks

Thats it the one to make the reading on your powertube socket. I don't know a whole lot about amps but I do recognize that fwiw.

So just to be clear, your saying the resister that is soldered to pin 1 and 8 on my amp is for this purpose or do I need to add another 1 ohm resister to what is already there ?

If you look close you can see the resister in the pics i posted.

Thanks

 

[sjk]

That's the one, take the reading from the lead between the resisistor and the pin it is soldered to.

 

[screamindemon]

awesome ! thanks