Dear fellow Rodents,

a friend of mine, who's a very keen jazz guitar player, asked me to make him
a small amp for home practice and/or small gigs. He plays a hollow-body
Ibanez Joe Pass (definitely not a HM axe) and wants a clean, nearly acoustic
tone. I found the schematics of the Fender Champ on the net, and I thought
it's just OK: SE class A pentode, say 5W out of a single 6V6, basic tone
controls, 3 tubes and that's all. But the PS ... well, it seems really
wimp. These days it would be difficult to find such small caps (8 uF). I
have a 40+20+20 can cap available and a small 5H choke, so I planned to make
a CLC filter (5Y3-20uF-5H-40uF-out to 6V6) instead of the original 8 uF C
filter.
The operating point will be exactly the same, DC is DC, and all the rest of
the circuitry and components will be exactly as the original (or just plain
originals as the OPT). The difference is just that the PS will not "sag"
when overloaded.
Do You think this could give a "bad" sound, from a guitar player viewpoint?

Thanks to all

Fabio

Fabio Berutti wrote:

Dear fellow Rodents,

a friend of mine, who's a very keen jazz guitar player, asked me to make him
a small amp for home practice and/or small gigs. He plays a hollow-body
Ibanez Joe Pass (definitely not a HM axe) and wants a clean, nearly acoustic
tone. I found the schematics of the Fender Champ on the net, and I thought
it's just OK: SE class A pentode, say 5W out of a single 6V6, basic tone
controls, 3 tubes and that's all. But the PS ... well, it seems really
wimp. These days it would be difficult to find such small caps (8 uF). I
have a 40+20+20 can cap available and a small 5H choke, so I planned to make
a CLC filter (5Y3-20uF-5H-40uF-out to 6V6) instead of the original 8 uF C
filter.
The operating point will be exactly the same, DC is DC, and all the rest of
the circuitry and components will be exactly as the original (or just plain
originals as the OPT). The difference is just that the PS will not "sag"
when overloaded.
Do You think this could give a "bad" sound, from a guitar player viewpoint?

It will give a fine sound, so build it to find out.

Patrick Turner.



Thanks to all

Fabio

Seeing as how a Champ is class A to begin with, why should
it "sag" when driven hard? The power tube is going to be drawing
the same amount of current whether the output is zero or full power,
right?

LV




Fabio Berutti wrote:

Dear fellow Rodents,

a friend of mine, who's a very keen jazz guitar player, asked me to make him
a small amp for home practice and/or small gigs. He plays a hollow-body
Ibanez Joe Pass (definitely not a HM axe) and wants a clean, nearly acoustic
tone. I found the schematics of the Fender Champ on the net, and I thought
it's just OK: SE class A pentode, say 5W out of a single 6V6, basic tone
controls, 3 tubes and that's all. But the PS ... well, it seems really
wimp. These days it would be difficult to find such small caps (8 uF). I
have a 40+20+20 can cap available and a small 5H choke, so I planned to make
a CLC filter (5Y3-20uF-5H-40uF-out to 6V6) instead of the original 8 uF C
filter.
The operating point will be exactly the same, DC is DC, and all the rest of
the circuitry and components will be exactly as the original (or just plain
originals as the OPT). The difference is just that the PS will not "sag"
when overloaded.
Do You think this could give a "bad" sound, from a guitar player viewpoint?

Thanks to all

Fabio

Yes, it's right, but I often read that guitar amps have a typical sonic
signature given by the PS. Some guys even write quite a few about the
difference among 5Y3s of different brand...
Anyway, thanks for Your help, it helped to clear out my doubts.

Ciao

Fabio


"Lord Valve" ha scritto nel messaggio
...
Seeing as how a Champ is class A to begin with, why should
it "sag" when driven hard? The power tube is going to be drawing
the same amount of current whether the output is zero or full power,
right?

LV




Fabio Berutti wrote:

Dear fellow Rodents,

a friend of mine, who's a very keen jazz guitar player, asked me to make
him
a small amp for home practice and/or small gigs. He plays a hollow-body
Ibanez Joe Pass (definitely not a HM axe) and wants a clean, nearly
acoustic
tone. I found the schematics of the Fender Champ on the net, and I
thought
it's just OK: SE class A pentode, say 5W out of a single 6V6, basic tone
controls, 3 tubes and that's all. But the PS ... well, it seems really
wimp. These days it would be difficult to find such small caps (8 uF).
I
have a 40+20+20 can cap available and a small 5H choke, so I planned to
make
a CLC filter (5Y3-20uF-5H-40uF-out to 6V6) instead of the original 8 uF
C
filter.
The operating point will be exactly the same, DC is DC, and all the rest
of
the circuitry and components will be exactly as the original (or just
plain
originals as the OPT). The difference is just that the PS will not "sag"
when overloaded.
Do You think this could give a "bad" sound, from a guitar player
viewpoint?

Thanks to all

Fabio

wrong - think clipping, which is typical for any guitar amp. Average current
will also vary for asymetrical waveforms.


"Lord Valve" wrote in message
...
Seeing as how a Champ is class A to begin with, why should
it "sag" when driven hard? The power tube is going to be drawing
the same amount of current whether the output is zero or full power,
right?

LV




Fabio Berutti wrote:

Dear fellow Rodents,

a friend of mine, who's a very keen jazz guitar player, asked me to make
him
a small amp for home practice and/or small gigs. He plays a hollow-body
Ibanez Joe Pass (definitely not a HM axe) and wants a clean, nearly
acoustic
tone. I found the schematics of the Fender Champ on the net, and I
thought
it's just OK: SE class A pentode, say 5W out of a single 6V6, basic tone
controls, 3 tubes and that's all. But the PS ... well, it seems really
wimp. These days it would be difficult to find such small caps (8 uF).
I
have a 40+20+20 can cap available and a small 5H choke, so I planned to
make
a CLC filter (5Y3-20uF-5H-40uF-out to 6V6) instead of the original 8 uF
C
filter.
The operating point will be exactly the same, DC is DC, and all the rest
of
the circuitry and components will be exactly as the original (or just
plain
originals as the OPT). The difference is just that the PS will not "sag"
when overloaded.
Do You think this could give a "bad" sound, from a guitar player
viewpoint?

Thanks to all

Fabio

well, speaking as a solid rock/blues guitar player who would only play
through a tube amplifier, and at the risk of getting flammed on this
newsgroup...I would suggest that your friend get a honking big solid state
amplifier with a high power speaker. Not for volume, but for cleanliness.
Try a Walter Woods amp and a Raezers Edges speaker cabinet...For a clean
jazz sound I would not suggest a tube amp at all (too big, and you never
want to run them into distortion anyway), and definitely not a small one
like a Champ.


"Fabio Berutti" wrote in message
...
Dear fellow Rodents,

a friend of mine, who's a very keen jazz guitar player, asked me to make
him a small amp for home practice and/or small gigs. He plays a
hollow-body Ibanez Joe Pass (definitely not a HM axe) and wants a clean,
nearly acoustic tone. I found the schematics of the Fender Champ on the
net, and I thought it's just OK: SE class A pentode, say 5W out of a
single 6V6, basic tone controls, 3 tubes and that's all. But the PS ...
well, it seems really wimp. These days it would be difficult to find such
small caps (8 uF). I have a 40+20+20 can cap available and a small 5H
choke, so I planned to make a CLC filter (5Y3-20uF-5H-40uF-out to 6V6)
instead of the original 8 uF C filter.
The operating point will be exactly the same, DC is DC, and all the rest
of the circuitry and components will be exactly as the original (or just
plain originals as the OPT). The difference is just that the PS will not
"sag" when overloaded.
Do You think this could give a "bad" sound, from a guitar player
viewpoint?

Thanks to all

Fabio