• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

my Dummy Amp Contraption

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
sorry about the title :clown:
even if it is all it will be in the end, I decided to build it anyway
but if lucky it will actually work too :rolleyes:
dont worry about the drawing, it will change
 

Attachments

  • C3g - KT88 PSE Garter bias.jpg
    C3g - KT88 PSE Garter bias.jpg
    61.5 KB · Views: 646
TheGimp

TheGimp

Member
Joined 2009
You need an anode load on the first Triode.

What are the red squares? Test Points?

Why tapped cathode resistors in the output tubes? That will just elevate teh grid and cathode by the voltage across the lower resistor.

Just tie the grid resistors to ground and use one resistor per cathode.
 
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
TheGimp said:
You need an anode load on the first Triode.
Click to expand...

yes yes, thanks

TheGimp said:
Why tapped cathode resistors in the output tubes?
Click to expand...

should be a Blumlein Garter bias, to compensate for uneven tube wear :confused:
(but maybe its just unneeded complication, and simpler would be fine)

btw, output tubes would be...EL34, KT66, KT88, KT100...
input/driver ?
I have some 6n1p or 6n6p
or even a C3g/6C19n(6S19p) combo
 
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
TheGimp said:
You need an anode load on the first Triode.

What are the red squares? Test Points?

Why tapped cathode resistors in the output tubes? That will just elevate teh grid and cathode by the voltage across the lower resistor.

Just tie the grid resistors to ground and use one resistor per cathode.
Click to expand...

OK :)

(looks like I can't afford to waste any voltage on the Garter bias)
 

Attachments

  • ecc99 - KT66 PSE.jpg
    ecc99 - KT66 PSE.jpg
    60.6 KB · Views: 187
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
thanks...yes I know

long time ago I asked about using Garter bias with SE
someone said it would work for SE as well
back then I still thought it wouldn't
beats me why I picked it up now

anyway, these days it should be fairly easy to get matched tubes from good suppliers

not perfect, never will be, but only hope its going to work ok :clown:
 
C

Carlp

Member
Joined 2006
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
Carlp said:
Put B+ into the "top" of the OPT (needs to be an SE OPT)....

But seems like you need to read up on SE amps???
Click to expand...

despite being a nice C-core, my OPT is a PP trafo
since its a C-core it may be air-gapped
but air gap is probably too small for SE
and unfortunately also low impedance

and the reason for choosing parafeed PSE ;)
(design with DC blocking cap)
(tempted, but not going to mess with 6c33, etc. )
(unfortunately original NOS EL/PL509 is not available any more)
(new EL509 ?...from what I have read it tend to be microphonic)
(NOS Kt100 ?...maybe, but getting expencive)
(6330 ? ... yeah, sounds like it would be nice, but also gone )
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom