• 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.

diagram for OTP 6.6K valve KT88

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alexg

alexg

Member
Joined 2005
Danchu said:
I have that OTP, but 6.6K is not populer, 5K is more common. In some schematic diagram, i don't find the paramet of OTP, so i want a schematic diagram, used OTP of 6.6K PP and i can DIY amplifier with my 6.6K OTP
thank
Click to expand...

Do you need schematic of the amplifier circuit or the schematic of the PP OPT?

If you need the schematic of an amplifier using KT88 in PP, you can use schematics that uses 5K OPTs and use your 6.6K OPT. Power will be a little bit lower (hardly noticeable) but distortion will be lower too.

HTH.
 
E

Eli Duttman

Member
Joined 2004
Danchu said:
thank eli duttman
but my OTP is very big, power about 50-70W, so amply with KT88 more suitable
if you have anyschematic diagram of amplifier PP of KT88
Click to expand...


Danchu,

The end to end impedance of your O/P "iron" is WRONG (too big) for use with KT88s. If you look at the 6L6GC data sheet, you will see that obtaining 50+ W. from a PP pair is not at all difficult. If you a willing to deal with the complexities of DC coupled MOSFET source follower drive, pushing the tubes into a positive control grid current regime (Class "AB2") is OK, as 6L6 control grids can safely dissipate some power. :)
 
D

Danchu

Member
Joined 2008
Dear All
I found some information for KT 88 (genalex KT88)

Push-Pull. Class AB1. Fix Bias. Untra Liner Connection. (40% tapping point)
Va, g2(b) 569 460 V
Va, g2(o) 553 453 V
Ia+g2(o) 2x50 2x50 mA
Ia+g2(max) 2x150 2x140 mA
RL (a-a) 4.5 4 kohm
*-Vg1(apro) 75 59 V
P out 100 70 W
Dtot 2 2 %
Pa+g2(o) 2x27.5 2x22.5 W
Pa+g2(max) 2x33 2x27 W
V(g1-g1)(ac) crest 140 114 V
Z out 7 6.5 kohm

But i don't fint any amplifier diagram used that
 
B

Bandersnatch

Member
Joined 2003
hey-Hey!!!,
So there you have the power stage. The rest is up to you. What does the front end of a PP stage need to do? Usually it is convert SE input to amplified PP output( to the power KT88 g1's). It would be easier to tell you how not to do it, than attempt describing all the ways it can be done.
cheers,
Douglas
 
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