Looking for Schematic 6550 tube amp triode mode more than 35Watt ?

[calico88]

Does anyone recommend this Schematic ? try googling but could not find that high output.

anyone ?

cal

[PeteM]

You will not get 35W from a pair of triode strapped KT88/6550's. class A.

[ray_moth]

As said in the other thread, you really need two pairs of 6550, in parallel PP, to get this much power in triode-mode. (If you were prepared to use ultralinear connection, then one pair of 6550 would be enough.)

[andRookie]

6550 40W se

Maybe you should have a look at this project. The designer and builder (jane) is also a diyaudio member. He has done many amps, and I`ve read on a norwegian forum that this one sounds very good.

[Yvesm]

Originally posted by andRookie
6550 40W se

Maybe you should have a look at this project. The designer and builder (jane) is also a diyaudio member. He has done many amps, and I`ve read on a norwegian forum that this one sounds very good.

Looks clean, but he uses 3 x 6550 in parallel

Yves.

[calico88]

the 3x6550 only 24 W in triode mode.
where is the triode and Ultra linear switch ?

I need more POWER on triode mode.

but this schematic is so simple....

I don;t think I can get the sowter OT anywhere locally except from ebay.
that's costly.

I wonder how much it cost to create this project ?


cal

[Yvesm]

If you REALLY need more power, forget triode and single ended.

Two 6550 will give you more than 60W in penthode mode at much lower cost.

Yves.

[calico88]

yes but I really need the triode mode, because of the sound quality reason.

why doesn't anyone design that triode high power ?
must be very very difficult ?

cal

[Alain Dupont]

calico88,

Going SE whatever tubes you use by paralleling more than 2 is costly
and need perfectly matched tube pairs or triplets or quadruplets.
{And in those cases tubes must be replaced more often}

From a DIYaudio point of vue more than 2 will become instable
and will need potentiometers in each cathode to adjust bias current
for each tube ; otherwise distortion will rise quickly.

One other solution would be to have 1 primary for each tube
and there the transformer will be much more costly...

So going after more than 2 tubes in parallel in SE mode is not douable
for you! with 6550's. It's why so few designs exists!

One Italian designer did a 3 * 6550 SE but uses custom made automatic
bias adjustment, and special opt's ...

A design has been published by Ari Polisois in AudioXpress last year using
3 parallel 6C33C-B tubes in SE configuration to get 45 watts ;
but it's not a simple project! {custom SE opt's ; big heat dissipation
and a bigger PS }

Further to get 40 watts pure class A in SE you need a tube {'s} with a plate
dissipation of more than 140 watts ; and with low internal impedance.
And a costly SE opt to get the best of this mode. Very few tubes with those
type of parameters exist!

Regards.

Alain.

[Salas]

Originally posted by calico88
the 3x6550 only 24 W in triode mode.
where is the triode and Ultra linear switch ?

cal

JP1 on the schematic?