valvecaster weirdness

Started by 23, March 15, 2009, 11:16:49 AM

Previous topic - Next topic

23

I got the caster built using Danos schem for PTP on the socket with the addition of a 3pdt switch/LED, it works but the volume is lower than the bypassed signal and its a little gated sounding here are my measurements...

1-4.42
2-88.0
3-0000
4-0.6
5-9.61
6-3.69
7-.7
8-000
9-4.75

I using a 9v wall wart and Ive double checked my caps/resis and they are right and my wiring seems to be right. I dont see any shorts or troubled joints. Im using a 12au7 tube and my pots are as noted by danos except I used a 100k instead of 50 k for the gain pot. the middle lug on the left says to ground it, but when I grounded in it wouldnt bypass I tried grounding it to the out put jack.. Any help is appreciated, thanks scott s
put it together, now take it apart

frequencycentral

Quote from: 23 on March 15, 2009, 11:16:49 AM
I got the caster built using Danos schem for PTP on the socket with the addition of a 3pdt switch/LED, it works but the volume is lower than the bypassed signal and its a little gated sounding here are my measurements...

1-4.42
2-88.0
3-0000
4-0.6
5-9.61
6-3.69
7-.7
8-000
9-4.75

I using a 9v wall wart and Ive double checked my caps/resis and they are right and my wiring seems to be right. I dont see any shorts or troubled joints. Im using a 12au7 tube and my pots are as noted by danos except I used a 100k instead of 50 k for the gain pot. the middle lug on the left says to ground it, but when I grounded in it wouldnt bypass I tried grounding it to the out put jack.. Any help is appreciated, thanks scott s

Here's mine, running at 12 volts, with the gain control set to maximum:

Pin 1: 3.02v
Pin 2: -0.518v
Pin 3: 0.00v
Pin 4: 0.00v
Pin 5: 11.97v
Pin 6: 8.21v
Pin 7: -1.285v
Pin 8: 0.00v
Pin 9: 5.91v

If you are running at 9 volts, all your voltages should be 25% less than mine.

Your pin 1 is too high.
Your pin 6 is too low.
Pin 4 should be 0v dead.
Your pin 2 must be a typo?

Are you sure you having switched to two plate resistor by mistake?
http://www.frequencycentral.co.uk/

Questo è il fiore del partigiano morto per la libertà!

23

My resis are right, my caps are right, my wiring is right, no bridges, no shorts, the thing works, it just sounds a little gated and lower volume than bypassed....

1-3.32
2-  -246.8
3-000
4-000
5-9.56
6-3.29
7-  -1.22
8-000
9-4.73


help me get this please........
put it together, now take it apart

frequencycentral

Quote from: 23 on March 15, 2009, 02:32:15 PM
My resis are right, my caps are right, my wiring is right, no bridges, no shorts, the thing works, it just sounds a little gated and lower volume than bypassed....

1-3.32
2-  -246.8
3-000
4-000
5-9.56
6-3.29
7-  -1.22
8-000
9-4.73


help me get this please........

Not trying to be funny, but if "My resis are right, my caps are right, my wiring is right, no bridges, no shorts" then it should be working correctly and giving loads of gain/volume above bypassed - and your voltages should be closer to mine.

Your problem is around the plate voltages, specifically pin 6.

Pin 2 still a typo?
http://www.frequencycentral.co.uk/

Questo è il fiore del partigiano morto per la libertà!

23

yeah i know  ;)  I think Ive jsut been looking at it for to long, gonna put it up for the day and look at it later, thanks tho. I hate when something almost works.... I've always heard "almost only counts in horseshoes and hand grenades."  :icon_biggrin:
put it together, now take it apart

frequencycentral

I've done dozens of builds including a huge modular synth and many tube pedals. Whenever I've finished a build I always get a sense of 'what dumb mistake have I made' despite checking everything three times. Most of my stuff fires up first time. But sometimes I do something dumb like forgetting an earth connection somewhere.

It's far better to think 'What dumb mistake have I made?' than 'I did everything right, why isn't it working?'.
http://www.frequencycentral.co.uk/

Questo è il fiore del partigiano morto per la libertà!