Dunlap Clarke Model Ten Preamp

[harrypj]

I posted some time ago about this preamp. It had some open caps when I received it. These have been replaced. My problem is the classic , " can't find anything wrong", but not working. Looking for some information on it. I have none.

 

[rayma]

Start with the power supply. Any DC voltages present?
If not, any AC voltages on the transformer secondary?
If not, any AC voltage on the transformer primary?
Some small transformers have an internal fuse.
If you don't have a DVM, go to a tech instead.

 

[harrypj]

Start with the power supply. Any DC voltages present?
If not, any AC voltages on the transformer secondary?
If not, any AC voltage on the transformer primary?
Some small transformers have an internal fuse.
If you don't have a DVM, go to a tech instead.

Done these tests, checks, Thanks for suggestions.

 

[harrypj]

For anyone interested, I have a signal coming through the preamp through Tuner and Tape inputs, but low. Full volume produces what level should be at less than half volume. No distortion, just low level.

 

[rayma]

For anyone interested, I have a signal coming through the preamp through Tuner and Tape inputs, but low.
Full volume produces what level should be at less than half volume. No distortion, just low level.

Maybe the gain is not too low, it can vary from one preamp to another. Are there input pots
on the back panel to adjust the levels?

 

[stocktrader200]

look for NFB blocking / bypass capacitors and replace them.

 

[rayma]

Do you have cables installed between "signal processor output" and "ext signal processor input" ?

 

[harrypj]

Maybe the gain is not too low, it can vary from one preamp to another. Are there input pots
on the back panel to adjust the levels?

There are no input pots. I put this into two different working systems. In both cases the output was very low compared to the preamp it replaced and there was no low level output.

 

[harrypj]

look for NFB blocking / bypass capacitors and replace them.

I have replaced and or check all capacitors.

 

[harrypj]

Do you have cables installed between "signal processor output" and "ext signal processor input" ?

I don't want to appear dumb, but I am not sure what you are asking here.

 

[harrypj]

I suppose what is needed here is a schematic. I have checked for cold solder joints, but it is not impossible I have missed one. This preamp is a little different in my experience. There was some thought on doing some things differently. For example there are two balance controls, one for the Left and one for the right.

 

[Raelyne]

Want to sale the preamp?

Want to sale the preamp. I will fix it. I have matching amps.. Raelynesatterfield@gmail.com is my email....