[RickH]

Has anyone worked with the idea of a 3 stage guitar amp like this?:

1) Tube preamp (maybe 6SN7, 12AX7, 5751, etc. with tone stack)
2) Tube power amp (single ended low power but overdriveable maybe a
6K6 or 6V6)
3) Solid-state final amp (Ideally just a pre-fab Class D module for
weight reduction, or possibly a pre-fab MOSFET module)

The idea is for the last stage to be linear, clean and lightweight.
The middle stage to simulate an overdriven power amp (when wanted),
otherwise it's clean. The first stage to be a clean stage that
respondse well to magnetic pickups and provides tone shaping.

What would be some of the major design obstacles in integrating these
stages? If stage 2 is single ended would 2 tubes and a SS module be
enough, or would another preamp stage be adviseable? Low weight is a
factor/requirement.

Thanks

[RickH]

On Sep 18, 12:23*pm, RickH wrote:
Has anyone worked with the idea of a 3 stage guitar amp like this?:

1) Tube preamp (maybe 6SN7, 12AX7, 5751, etc. with tone stack)
2) Tube power amp (single ended low power but overdriveable maybe a
6K6 or 6V6)
3) Solid-state final amp (Ideally just a pre-fab Class D module for
weight reduction, or possibly a pre-fab MOSFET module)

The idea is for the last stage to be linear, clean and lightweight.
The middle stage to simulate an overdriven power amp (when wanted),
otherwise it's clean. *The first stage to be a clean stage that
respondse well to magnetic pickups and provides tone shaping.

What would be some of the major design obstacles in integrating these
stages? *If stage 2 is single ended would 2 tubes and a SS module be
enough, or would another preamp stage be adviseable? *Low weight is a
factor/requirement.

Thanks

Filtered/regulated DC heaters would be nice too.

[RickH]

On Sep 19, 4:40*am, flipper wrote:
On Thu, 18 Sep 2008 10:23:26 -0700 (PDT), RickH





wrote:
Has anyone worked with the idea of a 3 stage guitar amp like this?:

1) Tube preamp (maybe 6SN7, 12AX7, 5751, etc. with tone stack)
2) Tube power amp (single ended low power but overdriveable maybe a
6K6 or 6V6)
3) Solid-state final amp (Ideally just a pre-fab Class D module for
weight reduction, or possibly a pre-fab MOSFET module)

The idea is for the last stage to be linear, clean and lightweight.
The middle stage to simulate an overdriven power amp (when wanted),
otherwise it's clean. *The first stage to be a clean stage that
respondse well to magnetic pickups and provides tone shaping.

What would be some of the major design obstacles in integrating these
stages? *If stage 2 is single ended would 2 tubes and a SS module be
enough, or would another preamp stage be adviseable? *Low weight is a
factor/requirement.

Thanks

Well, not 'quite' as you envision it but the same principle

http://flipperhome.dyndns.org/Gemini%20x2.htm

I didn't see any reason to 'limit' the SS power stage choices, or make
a custom design for that part. The low power 'tube guitar amp' just
plugs into whatever SS power amp you'd like, such as a home stereo
since most people got one. Or your choice of the lightest portable you
can find with the power you chose. Or use the P.A. at the gig and
carry just the small tube amp. The chassis is 4"x6"x2" high (4"
counting tubes).

Topology is a FET front end, two triodes preamp/phase splitter and two
triodes push pull power out. About 3/4W before clipping.

Knobs are preamp gain (you can overdrive it if desired), tone (Big
Muff style), and master volume. Clean or plenty of gain to grunge the
output to a square wave.

Front jack is for headphones.

Rear jacks are guitar hi-lo, speaker, (3.5mm) line out and, of course,
the wallwart jack.

Tubes are both 6BQ7/6BZ7.- Hide quoted text -

- Show quoted text -



Thanks,

Lots of questions...

Are you building these now flipper? I'd be interested in adapting one
in front of a class D module and using it as a DI box into my mixer
for recording. Is this a kit, chassis included? I am mostly
interested in running it clean/warm and am looking for lowest
background noise and hum (so thinking DC heater). Why 6BQ7? Is a
circuit board also available using the 12A#7 / 5751 family of tubes?
If not would it be easy to readapt the board to use 12A#7 tubes?
Cost? Can it get enough clean output to drive a power amp without
having to raise the gain (distortion) too much?

thanks
Rick