NAKD...: V2 Amplification 'Caldera"

ivan H said:
Ah, it's a good thing you did twist the heater wiring then, & yes, elevating the heater supply does get rid of AC heater induced hum as it makes the heaters positive in respect to the cathodes. I also agree with the more amp nerds the better. Cheers
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I don't like elevated heaters. It doesn't get rid of all the noise enough to make me happy.
I'm a filament curmudgeon.
I like my filament voltage to stay completely isolated from the other voltages.
 
V2a said:
6 volts to the preamp and PI tubes; 12 volts to the output tubes. All AC. It's a Kevin O'Connor design...
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if you are using pins 4 and 5 of the preamp tubes, (like in the photo above) that's 12 volts not 6.
If you connect pins 4 and 5 together, and use pins 4/5 and 9 for filament - that's 6 volts.
But in the photo it looks like pins 4 and 5 are the filament, pin 9 not used. That would be 12 volt. Like in a Suhr Badger...

I would think that running pins 4 and 5 with 6 volts would reduce the output of 12AX7 quite a bit...

" 12 volts to the output tubes. .."

If the output tube filaments are in series (2 filaments in series) then it could be 12 volt.
Otherwise output tube filaments in parallel must be 6 volt.
 
V2a said:
6 volts to the preamp and PI tubes; 12 volts to the output tubes. All AC.
Click to expand...
Amp Mad Scientist said:
if you are using pins 4 and 5 of the preamp tubes, (like in the photo above) that's 12 volts not 6.
If you connect pins 4 and 5 together, and use pins 4/5 and 9 for filament - that's 6 volts.
But in the photo it looks like pins 4 and 5 are the filament, pin 9 not used. That would be 12 volt. Like in a Suhr Badger...

I would think that running pins 4 and 5 with 6 volts would reduce the output of 12AX7 quite a bit...
Click to expand...

I had to edit my earlier post. 12V to pre, and 6 to output tubes. :)
 
V2a said:
I had to edit my earlier post. 12V to pre, and 6 to output tubes. :)
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Another issue is that AC filaments for preamp tubes are not quiet enough for me...
Unless using a secret "humbucking" filament wire layout. This is a special method which cancels buzzing using out of phase signals.
Otherwise I need DC filaments and I need a really low noise DC supply.
But I suppose that I am squeezing much more signal than a normal circuit, at a much higher impedance (like infinity).
I am never going to be satisfied unless I get infinite sustain from any note I play, without any effects pedals.

Yes I am mentally disturbed. I should be institutionalized.
This is what sets me apart: I shouldn't be allowed.

I suppose that most guitar players couldn't control it. It's my mental disability that's the real issue.
 
syscokid said:
Apparently I gave out some wrong info due to my lack of proper education on these things. And since I asked John McDonald about posting pics and details of his product here at TTR, he has been checking out how this thread is going and corrected me by stating this in an email a few minutes ago:
"PS. some notes about the amp (in reply to some of the posts on TTR):

- the heaters are AC with DC elevation. This means that the (artificial) center tap is connected to a high positive voltage (~50-75V) rather than ground. Seems to swamp noise. Also helps cathode followers. But don't untwist those nicely twisted wires... :)
- the OT is a hi-fi design with full-rated power down to 30 Hz. It's rated for 20W for hifi, but for guitar amps, it'll easily handle 30 watts.
- I don't rely on OT core saturation for limiting output power. Instead, it's a balancing of B+ and the primary impedance of the OT (here 6.6k rather than the usual 3.4k in EL34 designs..)"

I also suggested to John to hop on board at TTR. The more amp nerds, the merrier... right? :cheers:
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Is the OT an ultra linear type (what I would normally think a HiFi OT to be) & if so, is it ultra linear connected? Cheers
 
Thanks Sysco. It's a great looking kit & your build looks very well done.
A high primary impedance has long been used to limit plate current. The OT in my 5F1 Champ build is a reproduction of the OT used in the earliest Champs. Leo used surplus (6V6) car radio OT's. Primary impedance of 17k (more than twice the typical 8k) was to limit plate current. Of course, with the higher load impedance a larger voltage swing develops across the primary. Cheers
 
syscokid said:
It's that Canadian brotherhood thing. Wait till Session 5 gets back from flying his Godin golf cart from the woods... :run:
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Oh hes back....................................better duck and cover!

Checking in

Well as many of you know I am in and out right now spending the majority of my Summer at my getaway place. There has been much done in the last month. For starters we had a new deck built and a new gazebo. We just came off of hot hot weather a nine day heat wave 31 degree Celsius to 33 degree...
www.thetonerooms.com
 
eSGEe said:
Oh hes back....................................better duck and cover!

Checking in

Well as many of you know I am in and out right now spending the majority of my Summer at my getaway place. There has been much done in the last month. For starters we had a new deck built and a new gazebo. We just came off of hot hot weather a nine day heat wave 31 degree Celsius to 33 degree...
www.thetonerooms.com
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:hide: :hide: :hide: :hide: :hide: :hide: :hide: :hide: :hide: :hide:
 
syscokid said:
Very little done today. Added one resistor, then spent the next few hours preplanning where all the the final wiring and proper connections should be. Anyways, little by little, it's coming along.
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NO, a LOT done today - that pre planning counts as quality in your craftsmanship!
Dont sell yourself short.

I get a bit paralyzed by it some times ; indecision.
My JCM800 1w build has been in a holding pattern since April, almost finished fabbing the chassis.... sigh.

Good luck with your build Greg; I am tremendously excited about it!
Living vicariously I suppose.

ralph kramden dance.gif
 
jtcnj said:
NO, a LOT done today - that pre planning counts as quality in your craftsmanship!
Dont sell yourself short.

I get a bit paralyzed by it some times ; indecision.
My JCM800 1w build has been in a holding pattern since April, almost finished fabbing the chassis.... sigh.

Good luck with your build Greg; I am tremendously excited about it!
Living vicariously I suppose.
Click to expand...
Wow! Thanks... :cheers:

'Paralyzed by indecision' describes it perfectly, and it drives me crazy... o_O
 
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