Re: Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- From: "Savy" <savy@xxxxxxxxxxx>
- Date: 7 Feb 2006 15:56:14 -0800
Oh hey there Phil...thought you were my buddy Steve ragging on me again
! LoL
My main concern is in regard to the ever present noise inherant in this
amp which led me to upgrade various components. It is still noisy !
Class of operation concerns me for the potential to control the hum as
was intended in the circuits origional class AB1 mode of operation
(which is now in question).
My amp's circuitry was designed for Class AB1 with 6V6s (a quieter mode
of operation than class than class A... like what a humbucker is to a
single coil pup....yes?)
I Thought that perhaps my now using 6L6 tubes intended to operate at
450 volts in higher powered amps might be problematic when subbed into
a circuit designed for 6V6s with a max operating voltage closer to 350.
My transformer can only provide but 390v topps.
Specs show the old 6v6s to have max. values in the neighbourhood of 350
volts for both the plate and the screen grid (G2) in class AB whereas
the new 6L6s are charted at 400v on the plate and as low as 250v on G2
for the samp class of operation (within a similar W dissapation). One
can see from those figures alone that there might be cause for concern
because of the apparent difference in voltage ratios for the different
tubes.
For noise control I do desire class AB but am concerned that I will not
be able to adjust out the noise with the 6L6 spec plopped into a socket
rigged for 6v6 specs.
Question... If I reconfigured my bias supply to go lower (less
negative) could it be simply a matter of raising the 6L6 plate voltage
to max available in this amp (390v). How would this affect the screen
grid voltage(G2). Would there potentially become more of a spread in
voltage values between the plate and G2 to reflect Class AB specs for
the 6L6. (I'm not quite sure of the inter-relation of the two.) ? I do
suspect that with the 6L6s in place now with approximately equal plate
and G2 voltages (around 350 ea.) that it is outside of Class AB and
more like class A.(cool for tone but bad for noise).
Noise is what I've been trying to nail down first then tweak the tone
once things are quiet and stable.
I am a natural musician who plays by feel but when it comes to
troubleshooting the intricies of a potentially great sounding tube amp
I can't help but question the numbers for a clue beyond hit and miss or
settling for "good enough".
All advice is learning and much appreciated.
Savy
It actually doesn't sound half bad as it sits... could be quieter for
sure.
I posted the figures because of a questionable discrepancy in voltages.
Specs show that 6L6 in
So again...
.
- Follow-Ups:
- Re: Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- From: Phil S.
- Re: Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- References:
- Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- From: Savy
- Re: Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- From: Phil S.
- Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- Prev by Date: Re: OT - Bush on
- Next by Date: Re: Princeton Reverb Repair
- Previous by thread: Re: Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- Next by thread: Re: Hey...back to TUBES ! :o) 6V6 - 6L6 help please
- Index(es):
Relevant Pages
|
