Make sure your cathode bypass on V1 is right.
That is if you used two different value plate resistors, make sure the cathode cap and resistor is paired with the right section of tube.
In other words, V1a and V1b.
Hi Tom
I believe these to be lined up right...V1a 220k/3.3k V1b 150k/2.2k
Revisited the fx loop out to another amp...Hope this is the right to do it.
I have a one cable from the send of bad amp to power amp input of good amp...sputtering. I run the opposite way ...send of good amp to in of bad amp...sputtering.
Not sure which way to go from here...
Darin
So if you output your HRM preamp to a good power amp you get the sputter.
If you output the good amp preamp into your HRM power amp you get sputter.
Just so we're clear, Send is out and Return is in.
That really doesn't make sense.
For the preamp and power amp to have the same symptom, unless it is power supply related.
How are your filter caps?
Describe your dropping string in the power supply.
This is a quote from the Valve Wizard.
Again, the value of the capacitors is not critical, although if they are too small the amp may be prone to low frequency oscillation, or motorboating. This is a common problem in older amp, especially if the cap's have dried up over time. For the stiffest power supply we again use: C = 1 / (2 * pi * R). Smaller values are often used, but the low frequency response of the associated preamp stages should be carefully attenuated, using small coupling/cathode bypass cap's, if motorboating is to be properly avided. Values from 22uF to 220uF are typical.
Structo wrote:So if you output your HRM preamp to a good power amp you get the sputter.
If you output the good amp preamp into your HRM power amp you get sputter.
Just so we're clear, Send is out and Return is in.
That really doesn't make sense.
For the preamp and power amp to have the same symptom, unless it is power supply related.
How are your filter caps?
Describe your dropping string in the power supply.
This is a quote from the Valve Wizard.
Again, the value of the capacitors is not critical, although if they are too small the amp may be prone to low frequency oscillation, or motorboating. This is a common problem in older amp, especially if the cap's have dried up over time. For the stiffest power supply we again use: C = 1 / (2 * pi * R). Smaller values are often used, but the low frequency response of the associated preamp stages should be carefully attenuated, using small coupling/cathode bypass cap's, if motorboating is to be properly avided. Values from 22uF to 220uF are typical.
Darrin when you send the preamp of the bad amp to the power amp of the good amp,insert another cable or just a 1/4 plug to the return jack of the bad amp.That way you will break the connection between the preamp and the power amp of the bad amp and you should have sound only from the good amp.
dimitris wrote:Darrin when you send the preamp of the bad amp to the power amp of the good amp,insert another cable or just a 1/4 plug to the return jack of the bad amp.That way you will break the connection between the preamp and the power amp of the bad amp and you should have sound only from the good amp.
Structo wrote:Did you install a choke on this amp?
Tom,
yes choke ohms at 110...I have another I could try?
ran a cable as dimitris suggested which silenced the speaker from bad amp...but still have the sputtering. And both ways.
In some of the pictures the leads on the 22uF caps in the power supply look close to the can on the 100uF cap. Bend the leads to give more room between the 100uF cap body and the ground leads of your B+ string.
Could cause the ticking, and read O.K. voltages with low current demands of the meter or light playing but mess things up when digging in...
Structo wrote:Hmmmm, have you checked to see if your filter caps are leaking a lot of AC?
Check for AC voltage where the two plate resistors on V1 join.
Amp on, set meter to AC, ground black lead and touch the red probe to the junction of the 200K and 150K.
Do that on each node. (V2, V3)
There shouldn't be any significant AC voltage there.
Tom
checked this and no significant AC voltage less than .027 or so.
ER wrote:In some of the pictures the leads on the 22uF caps in the power supply look close to the can on the 100uF cap. Bend the leads to give more room between the 100uF cap body and the ground leads of your B+ string.
Could cause the ticking, and read O.K. voltages with low current demands of the meter or light playing but mess things up when digging in...
Thanks ER
I have the ticking/clicking solved
now I get a sputtering/cutting out when digging in
I will change the leads regardless.
If you can't get it to stop sputtering, you could always sell it to Henry Kaiser
Sorry couldn't resist!
Have you checked the undersides of the boards to make sure their's not a lead that forgot to get clipped? Blow out the amp with compressed air? Bad tube?
Don't worry you'll get there, I always have learned as much or more from trouble shooting as from building the amp, and when it's solved it's all the sweeter. Don't get discouraged.
If you get frustrated take a break and sleep on it, you'll be surprised what ideas pop into your head when you step away for a bit.
Where are you at? Maybe there's somebody local that could help out. As they say two heads are better than one, figuratively of course, not literaly like Larry Carlton.
Thanks Tom, ER
Taking a break from it...its probably something silly like Tom says
I'm kinda in the middle of nowhere...At one point Gary...glasman
offered some assistance on another build a while back,
he's about 200 miles away in Phoenix, AZ...
I may try to contact him and see if the offer still stands.
I think Henry Redplate Amps is in that area also, not sure
