Enclosed is a picture of how I have wired up the Parefeed Darling.
But the weirdest thing is happening...If only feed it with one channel...sound emenates from BOTH speakers. From the one a little distorted though. If I feed the same signal into the other channel...there is no sound from EITHER speaker?
Baffled!?!?!?? Anyone have an idea what it can be? I was thinking it might have something to do with the CCS's and no decoupling from the PSU?
Regards,
Bas
But the weirdest thing is happening...If only feed it with one channel...sound emenates from BOTH speakers. From the one a little distorted though. If I feed the same signal into the other channel...there is no sound from EITHER speaker?
Baffled!?!?!?? Anyone have an idea what it can be? I was thinking it might have something to do with the CCS's and no decoupling from the PSU?
Regards,
Bas
Attachments
Nothing on the scope? Oscillating maybe?
Although there are numerous things that I would do differently, and some of which are bad design practice, I'd check the 6.8uF cap. Everything's fed with a CCS but I still don't like it so small.
Tim (who recently completed a preamp drawing maybe 20mA but using 220uF in the PSU anyways 😀 )
Although there are numerous things that I would do differently, and some of which are bad design practice, I'd check the 6.8uF cap. Everything's fed with a CCS but I still don't like it so small.
Tim (who recently completed a preamp drawing maybe 20mA but using 220uF in the PSU anyways 😀 )
Well just like I would do at work when a control valve isn't working you start troubleshooting at the PSU. You could also hook up a tone generator and test for a signal after each stage. The only thing the two channels have in common is the power source (generally speaking) and the heater supply. That is where I would start. Also a faulty tube could allow a signal to pass from the cathode to the heater( or vice versa ) if the 1626 is a indirectly heated tube. This is just a semi-educated guess. You should be able to find it with a scope fairly quickly.
Thank for helping...Problem is I don't have a scope...I'll just recheck everything...
Cheers,
Bas
Cheers,
Bas
If you have a analog multimeter you can check the output of each stage of the offending channel in AC mode and you will be able to narrow it down to which stage the problem is rudely lurking in. Double check every connection against the schematic and be on the lookout for cold solder joints. If you took your time and concentrated when building the circuit then the problem should be easy to identify if approached in a logical step by step fashion. Check the B+ at the plates of the tubes and check across the cathode resistors for the desired bias voltage. Are the tubes NOS? Have they been tested for shorts? Post back with any strange readings or if you let the smoke out of anything.😉 😉
Bas,
What is the difference in voltage between +B and +b ?
(Glad it's only this 'darling" you're having problems with...😉 )
What is the difference in voltage between +B and +b ?
(Glad it's only this 'darling" you're having problems with...😉 )
150volts dc...well dc...;-)
Well it's not actually..but that the other one I don't ask questions about on forums....there is no help possible there..!!!
No they have not been teste for shorts...I might try some others...and will report later if I find some odd readings...
Cheers and thanks y'all..
Bas,
double check your wiring first, a mistake is easily made, hence no output from the other channel at all.
Second, replace all the CCS with 10k high power resistors for troubleshooting. See if you get sound out of both then.
Dick.
double check your wiring first, a mistake is easily made, hence no output from the other channel at all.
Second, replace all the CCS with 10k high power resistors for troubleshooting. See if you get sound out of both then.
Dick.
Thanks DJ...
I will...have not given it much time because of my real life darling...
You are into tubes as well? How did you get them? I ordered them from the states....I have 2 more spare..so I don't need them right away..but might take you up on your offer...what are they going for?
Did you get the pot?
Please not so loud Bas. Nobody knows it yet 😉
Send me a PM if you need them. I got the pot, thank you for that.
Hi, Bas!
Nice to see you are in investigations.
Is this amp for headphones?
What I'd think..
1/ Are you sure the resistors 47 in Ohms? They have to be 47k.
2/ As for neon stabs.. IMO - you don't need it at all.
3/ Better check grounding of each part.
Rgs, Igor.
Nice to see you are in investigations.
Is this amp for headphones?
What I'd think..
1/ Are you sure the resistors 47 in Ohms? They have to be 47k.
2/ As for neon stabs.. IMO - you don't need it at all.
3/ Better check grounding of each part.
Rgs, Igor.
The 47R are plate stoppers...The CCS replaces the plate resistor that is often 47k.
I use them to get voltage down to 150 instead of 300V. They are indeed not strictly neccesary. But they look nice! ;-)
Yes will check...still have not had time to debug it...
PS...it is a power amp ....but might use it as a headphone as it is not powerful enough for my current speakers.
Cheers,
Bas
My darling is making beautiful music
I replaced the CCS's with resistors... and voila...
Somehow I was not happy because that means all the work put in the CCS was in vain....well nog completely ofcourse..but I will have to debug them now :-(
Cheers and thanks very much to all who provided me with input...I think by the way that this is the way I will do things first....use plain reliable resistors...if the circuit works as intended only then proceed with the CCS's.
Regards,
Bas
I replaced the CCS's with resistors... and voila...
Somehow I was not happy because that means all the work put in the CCS was in vain....well nog completely ofcourse..but I will have to debug them now :-(
Cheers and thanks very much to all who provided me with input...I think by the way that this is the way I will do things first....use plain reliable resistors...if the circuit works as intended only then proceed with the CCS's.
Regards,
Bas
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