Current draw with KT66s in place...to much!

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danman
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Re: Current draw with KT66s in place...to much!

Post by danman » Sun Feb 01, 2015 12:21 pm

Glad to hear that you got it fixed! I have always heard good reviews for "Antique Electronic Supply" (tubesandmore) on their tube matching and warranty. They are also located in your area I believe. Tube Depot is another supplier that seems to do a good job of matching and warranty of their power tubes.

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Re: Current draw with KT66s in place...to much!

Post by ValveStorm » Sun Feb 01, 2015 12:46 pm

Not sure I have heard what the actual problem with the amp was? Looks like a 100k PI tail resistor in the pics? What is the value of that NFB resistor?

Don't get a new pair of KT66s from tubesandmore.com... that would be where your first set came from!
ValveStorm.comParts, parts parts!

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neikeel
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Re: Current draw with KT66s in place...to much!

Post by neikeel » Mon Feb 02, 2015 9:44 am

ValveStorm wrote:Not sure I have heard what the actual problem with the amp was? Looks like a 100k PI tail resistor in the pics? What is the value of that NFB resistor?!
Yes it does, I did not see that. The amp would still have worked with that - just very compressed and reduced volume (I bought an SB once where someone had put a 100k presence pot in and wondered why it was so quiet!). NFB looked like 27k cc.

Who are the decent tube dealers in the US? In the UK I tend to use Hotrox or Watford valves (if they have a deal or special, otherwise they are a bit expensive). Both are pretty much out of NOS stuff. Not heard from Trampy here for a while - he usually pipes up if has good stuff to sell.
Neil

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Re: Current draw with KT66s in place...to much!

Post by ?Mark » Mon Feb 02, 2015 7:21 pm

nope, Valve Storm
It always had a 10k for tail.
The NFB resistor is 27K.

I've installed a PPI-MV
and was wondering about
loss of NFB from lower Pwr tube
output as its rolled off, any thoughts?
Maybe going to a variable pot
for the NFB instead of the fixed
27K NFB resistor?

?Mark
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Re: Current draw with KT66s in place...to much!

Post by ?Mark » Tue Oct 06, 2015 2:53 pm

Hi guys!

Been a while...
All is well with me and my JTM45.

Put 1k ohm and 470 ohm on a DPDT switch,
easier to switch to EL34 now. I also move OT
to 16 ohm for 8 ohm spkr imp.

OMG, with a pair of 6L6 RCA Black Plate I
get clean smooth head room for days.

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