[cfcubed]

Quote:

Just wondering if there's any (dis)advantage if I bump the C4L/C4R to 0.47uf? Just found some 0.47uf Vit Q in the parts bin and they seem to fit just fine, not really any bigger than the 0.22uf that I thought of using.

0.47s should work but you'd want to test this on the bench before re-boxing, e.g. the e12 latch behavior.  I tried 1ufs I'd around & my e12 latch was more touchy.  You do not nee more capacitance there tho, so you should only notice the difference in the sound of the caps (rolloff is low enough w/0.22s).
 
Quote:

Yeah I have one and I guess I need to go pick up another tomorrow. I guess adapters will work for now but I will eventually want to switch them out on the cth if I can. If not I will atleast have an amp to look at and study and hopefully be able to build my own. I know it was built way before the rev a specs. Did the original cth call for the 1/8 input/output? I cant imagine why this would be the only option the original builder went with.

Many CTHs were built w/1/8s in & out (e.g. they were/are in the BoM) to make the fit easier in the tiny hammond target box.  It's a bit harder to fit 1/4" out + RCA in but many have done that as well (e.g. my avatar).  There's no technical reason for these diffs, only difficulty of fitment.

 

[Lil' Knight]

Thanks. I'll try both the 0.22 and 0.47 to see how the e12 responses.
Just also ordered a GrubDAC to cramp into the case, would be a nice, tiny USB DAC/amp.

 

[schwallman]

0.47s should work but you'd want to test this on the bench before re-boxing, e.g. the e12 latch behavior.  I tried 1ufs I'd around & my e12 latch was more touchy.  You do not nee more capacitance there tho, so you should only notice the difference in the sound of the caps (rolloff is low enough w/0.22s).
 

Many CTHs were built w/1/8s in & out (e.g. they were/are in the BoM) to make the fit easier in the tiny hammond target box.  It's a bit harder to fit 1/4" out + RCA in but many have done that as well (e.g. my avatar).  There's no technical reason for these diffs, only difficulty of fitment.

Ok. Ive only seen pictures of various builds. I'm really not even sure of the size since I've never seen one in person.

 

[revolink24]

So I finally "finished" my first CTH today, but it's not working (as is usually the case). The E12 LED comes on red, and doesn't change. Measuring between OG and SG seems to fluctuate between about 5v and 11v. Very strange. Does anyone have any idea what might be going on?

 

[sachu]

measure the voltages on the opamp in the rail splitter and the dual opamp in the buffer section and post your values. All wrt SG.

 

[schwallman]

Can the pcbs still be bought? Most likely from someone that got in on the last group buy I would guess.

 

[revolink24]

ICR:

Pin 1: 35 mV
Pin 2: 1.5 V
Pin 3: 1.5 V
Pin 4: 0 V
Pin 5: 36 mV
Pin 6: 1.07 V
Pin 7: 14.58 V
Pin 8: 0 V


IC1:

Pin 1: Varies, approx. 6.5-9.5V
Pin 2: 0 V
Pin 3: Varies, approx. 7.2-9.3V
Pin 4: 0 V
Pin 5: Varies, approx. 7.2-8.5
Pin 6: 0
Pin 7: Varies, 8.5-11V
Pin 8: 14.5V

Pretty strange readings....

 

[sachu]

Measure ICS..that's the rail splitter. The output of that needs to be at 12V.
 
Measure output of the 24V regulator.

 

[revolink24]

Heh, that was silly, right you are.

Pin 1: 0.37 V
Pin 2: Varies, 6 - 9.5 V
Pin 3: 12V
Pin 4: .3V
Pin 5: 6 - 10V
Pin 6: 14.5 V
Pin 7: 14.5 V
Pin 8: 0 V


I'll have to get back to you on the 12V reg, I can't reach it without getting the board back out of the case.

 

[revolink24]

I also scoped the output, and whether the power is on or off, the output is seemingly a 60 Hz square wave. I'll check my grounds.

 

[cfcubed]

revolink24 - Could you please conduct the setup test here & let us know the voltage readings from it?:
http://www.cavalliaudio.com/diy/cth/main.php?page=setup
Most measurements are WRT SG.  Also please let us know the heater readings (voltage bet pins #4 & #5) for both 6V & 12V heater switch positions.
E.g. I don't see any HV in your readings.
 

 

[revolink24]

Okay. here goes.


Tube readings:

12.6V


Pin 4: 0 V
Pin 5: 12.7 V
Pins 1 and 6 reads 80 V.

6.3 V:

Pin 4:

4: 0V
5: 6.3V
1 and 6: 80V

Tests from site.

OG - fluctuates between 6V and up to 10.2 V
OL, OR fluctuate similarly.

TB+ reads 105V.

 

[sachu]

wait, is Pin 1 and 6 reading with the Tube inserted?

 

[revolink24]

Nope, D'oh! They are reading 80V now with the tube inserted.

Drop across 4 and 5 also reads 12.6V.

I think there's floating AC somewhere in the circuit that is causing the E12 to trip, or at least thats the only conclusion I can think of.

 

[revolink24]

Still cant find any problems with my ground. Anyone else have any ideas?