[sonata149]

Having been impressed by the Bugle kit I wanted to try out the cornet before commiting myself to buy that kit. Besides I have a valve SE807 amp. I scratch built the Cornet on a pcb for a similar circuit but had to make some changes. Connecting it to my system this morning I found lacked body around the instruments/vocals, but especially it lacked bass    It sounds cheap compared to the Bugle 

As for changes, I left out C1 and C3 (1uF across the PS caps), used a 240V secondary bridge rectified (SS) followed by a 10H choke (CLC). Reduced R2 to 1K0 to bring the voltage to V3 closer to the prescribed 330Vdc. Otherwise, it follows the April 2006 - Rev B schematic with the MJE-340 for CCS.

I tried substituting various valve brands (also ECC81s for 83s) but the sound remained practically the same.  Can someone who is more technical and informed on the forum tell me which areas could be the culprit for this lack of bass? Also, is there a link for the voltages I should get around the various valves/CCS.

Thank you all so much for a very interesting forum.

[amandarae]

You should be able to download the pdf manual of the Cornet from Jim's site.  It shows the test points for various voltage reading when checking up or troubleshooting the circuit.

[sonata149]

Thanks amandarae.

It just happened that the circuit I was working from was the one with the preamp and power supply on same sheet.  Now that I know these other voltages I will check my work and report back.

Thanks for your help.

[hagtech]

Double check the capacitor values.  Sometimes I switch between 0.001uF and 1nF.

jh

[sonata149]

For the sake of those kind members who supplied info or suggestions, as well as those who have followed this thread, I'm glad to report problem solved. To cut a long story short I had C202 (47nf) missing!! Stupid of me yes, but then I was'nt using the standard PCB - that's another reason for using the manufacturer's parts!!  Lesson is if you have a flat, bass-less sound, then check this component.

I'm listening to it right now after some fine-tuning of the heater and HT supplies. The sound is excellent!! Great though the bugle is, the Cornet is that bit better - separation, 3-dimensionality, fluidity of sound (the valves?), detail and yes, the bass is there - maybe not as impressive as the Bugle (flabby?) but quite tight. Now I'm driving my speakers with just about 8W of SE valve power. Definitely thumbs up then for the Cornet as most of the users have said, repeatedly, on this forum and elsewhere.

Now starts the second phase: Tube Rolling, etc...