6V6 HRM

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dcribbs1412
Posts: 1386
Joined: Wed Jun 11, 2008 6:56 pm
Location: Arizona Desert

Re: 6V6 HRM

Post by dcribbs1412 »

Tony
Can I come out of my D'lite loop and into the HRM loop?
talbany
Posts: 4696
Joined: Tue Mar 28, 2006 5:03 am
Location: Dumbleland

Re: 6V6 HRM

Post by talbany »

dcribbs1412 wrote:Tony
Can I come out of my D'lite loop and into the HRM loop?
Yes...Dlite send to HRM return..Let us know what gives..

Tony
" The psychics on my bench is the same as Dumble'"
dcribbs1412
Posts: 1386
Joined: Wed Jun 11, 2008 6:56 pm
Location: Arizona Desert

Re: 6V6 HRM

Post by dcribbs1412 »

After Norm's suggestion about the PI
I changed the PI resistors(110k,100k) and caps(.1 6PS)...no luck
then I changed the NFB resistor from 5.6k to 47k and plucked a chord
and no thumping. :) Was able to crank it pretty good and no motor-boating
(if that is the correct term for this anomaly)
other than the graininess(see below)
Not sure what exactly I did wrong....was it coincidental?

I do have a sizzle or grainy sound in the back of notes and chords both
clean and OD. Tried a few different speakers same thing.Tried a few tubes in V1 V2 and V3 no change...
Will be dropping some voltages ASAP as I have 320v now on V3..could this be causing the graininess?

Darin
dcribbs1412
Posts: 1386
Joined: Wed Jun 11, 2008 6:56 pm
Location: Arizona Desert

Re: 6V6 HRM

Post by dcribbs1412 »

After a few more changes (dropped voltages to V3 to 305,310 V2 200,195 V1 190 ,185 loop 245,215)
I still have the graininess on both clean and OD channels
also when I set the imp to 4 ohm the thumping is still there(not as bad)
no thumping on 8 or 16 ohm
any ideas are appreciated

Thanks

Darin
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Structo
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Joined: Wed Oct 17, 2007 1:01 am
Location: Oregon

Re: 6V6 HRM

Post by Structo »

Do you mean you changed the NFB resistor to 4K7?
Tom

Don't let that smoke out!
dcribbs1412
Posts: 1386
Joined: Wed Jun 11, 2008 6:56 pm
Location: Arizona Desert

Re: 6V6 HRM

Post by dcribbs1412 »

Hi Tom
changed it to 47k
now the thumping is only when I switch to 4ohm on selector?
the graininess is still there...clean and OD
any ideas?
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