Ceriatone ots, hrm.

[mcinku]

Do you have a recording rig... You could make a before/after clip...

...at least this way you will know it's not you... or better yet, we will know it's not you.

[Frankie]

Ear fatigue? Have you tried playing other amps and see if you hear a change at about the same time?

a'doc1

Yea I play other amps all the time to.
I have bruno underground 30, cowtipper II, a marshall bluesbreaker, a marshall jmp -72 50w, fender dual professional 100w, IT never changes when I use my other amps. So this is only on the ods, and hrm amps.

[erwin_ve]

Maybe you can start posting the voltages before and after the problem. Voltages at the dropping string and cathode and plate. at v1, v2 and v3.
Bias current before and after problem would be appriciated too.

If you like people here to help you post as much tech detail about the amp as possible.

[Frankie]

Maybe you can start posting the voltages before and after the problem. Voltages at the dropping string and cathode and plate. at v1, v2 and v3.
Bias current before and after problem would be appriciated too.

If you like people here to help you post as much tech detail about the amp as possible.

The voltages are the same, thats the big problem here, I can`t read any of the problems in voltage changes. :(
I also have checked the voltages during playing, but they are the same.

[Structo]

This all doesn't make much sense at all.
If there is a change in tone after warm up, it is either tubes or something that can be measured.
Having two amps that do the same thing is the real puzzler.

[Frankie]

This all doesn't make much sense at all.
If there is a change in tone after warm up, it is either tubes or something that can be measured.
Having two amps that do the same thing is the real puzzler.

Could it be some sort of parasite oscillation then?
I changed the biggest lyth.. caps on the board from 100 uf 500v to 220 uf 350 v. And the coupler between v1b, and the od v2a from 0,05 to 0,02.
Now the problem is like this, I play 5min and then the sound is getting harder, and loose some of the warm, and this is causing the overdrive to be thinner, a little fuzzier also. The amp don`t seem to hold up and stay tight.
If a wait 2 min the sound is huge and full again. The problem is getting worse if I change between the cl and the od , seems like it need a couple of minutes before the signal level is back to normal volum!
??
This is on the hrm amp, haven`t started to do anything with the ods yet.
I need to solve this problem cause I`m starting on the third ods soon, after I`ve built two dlators. And I don`t want to end up with this problem on that one too. Grrrr!
Anyone who sell cab for the natchakom@hotmail.com chassis??

[bcook]

A couple of shots in the dark:
Make sure your tube grids have some kind of DC path to ground.
Figure out if it's in the preamp or power amp - plug the other preamp into the return loop when it starts acting up. You've got to narrow it down.

[Structo]

So you doubled the first filters?
These are 50 watt amps right?

That may be too much filtering, which can cause some problems, not sure if it would cause what you are experiencing.

What size bypass caps are you using on V2?

Can you post some pictures of your amp?

[talbany]

I KNOW WHAT'S WRONG!!

[Sonny ReVerb]

Priceless, Tony!

[67plexi]

Frankie. What brand of electrolytic capacitors did you use?
On a voltage doubler power supply wired in series let us hope so
100uf x2 is good for 50-60 hertz filtering two 100uf @ 500vdcin series would give you 50uf @ 1000vdc
This would give you a nice fat midrange.
220uf @ 350vdc will give you 110uf @ 700vdc in a voltage doubler power supply
This would give you a thin sound and cut out the midrange.
You have a capacitor reactance issue when the 220uf charges up 5 min. and stabilizes you just killed the midrange or the new caps cant take it, get out the esr meter and test or scope it.
Also the capacitors of today’s manufacture are fair at best you should buy the best Electrolytic money can buy if it were me I would try the new sozo 67 royle series 100uf @ 350vdc made in usa
When it comes to power supply filter capacitors don’t go cheap
The energy stored by a capacitor is calculated by:

where J = energy in Joules
C = capacity in Farads
V = voltage in Volts

Good one Tony I almost fell off my chair

[Frankie]

Frankie. What brand of electrolytic capacitors did you use?
On a voltage doubler power supply wired in series let us hope so
100uf x2 is good for 50-60 hertz filtering two 100uf @ 500vdcin series would give you 50uf @ 1000vdc
This would give you a nice fat midrange.
220uf @ 350vdc will give you 110uf @ 700vdc in a voltage doubler power supply
This would give you a thin sound and cut out the midrange.
You have a capacitor reactance issue when the 220uf charges up 5 min. and stabilizes you just killed the midrange or the new caps cant take it, get out the esr meter and test or scope it.
Also the capacitors of today’s manufacture are fair at best you should buy the best Electrolytic money can buy if it were me I would try the new sozo 67 royle series 100uf @ 350vdc made in usa
When it comes to power supply filter capacitors don’t go cheap
The energy stored by a capacitor is calculated by:

where J = energy in Joules
C = capacity in Farads
V = voltage in Volts

Good one Tony I almost fell off my chair :D

I use the electrolytic from" tube amp doctor" (TAD), should be a good brand. Costs about 12$ each.
First I used those from ceriatone 100 uf 450 v. (Was in the kit.)

[llemtt]

please Frankie post enough info...

all the voltages before and after warmup including voltages at tube grids

detailed picts of the chassis

sound samples

I would suggest a coupling capacitor leakage or something similar

thanks
Teo

[Frankie]

please Frankie post enough info...

all the voltages before and after warmup including voltages at tube grids

detailed picts of the chassis

sound samples

I would suggest a coupling capacitor leakage or something similar

thanks
Teo

Pictures HRM.

[Frankie]

please Frankie post enough info...

all the voltages before and after warmup including voltages at tube grids

detailed picts of the chassis

sound samples

I would suggest a coupling capacitor leakage or something similar

thanks
Teo

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