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152.163.101.6
In Reply to: 45-845: refined classic v hybrid posted by rick57 on September 5, 2006 at 14:45:26:
RichardYou could build Jim's v5 IT version - an IT can do class A2.
Lower the Vbias which raises the Ip making A2 operation posible.
Why you want the hybrid with the posted graph is beyond me.
So much upper harmonics would kill the music.
But it is your money 8^DDanL
Follow Ups:
Hi DanThe graph you posted is at *30 watts. At 10 watts (nearly half way down the link) eg the 3rd harmonic is – 70 dB, 4th – 92 dB,
Yes Jim’s V5 is a good option, are there graphs available of it at either 10 or 30 watts?
Cheers
Richard> > The graph you posted is at *30 watts. At 10 watts...
If you only need 10W then why go A2?
You'll get 20W without going into A2.
How efficient are your speakers?
If they're over 90dB then you don't need A2.> > are there graphs available at either 10 or 30 watts?
A2 operation you really hear the driver,
you are seeing/hearing the SS power supply
used for the grid drive which being SS
will have more higher order distortion.
With Jim's A2 circuit you will see/hear
the driver and IT both of which will have
mostly 2nd order distortion.
So with Jim's circuit you will hear mostly
2nd order and with the tubelab higher order.
I prefer mostly 2nd myself, it's more musical.From the tubelab website:
> > The second harmonic is dominant up to about 15 watts
> > then the third shows up.So 15 watts in A1.
> > Most of the distortion is...generated in the driver (45).
Driver - YES
45 - NO
45 is one of the lowest distortion tubes made.> > The driver clips before the output stage clips
> > because the 400 volt supply is not high enough.Very poor design then.
Output stage should clip before the driver stage!!!
So the 45 is clipping and being amplified by the 845.
That will sound VERY NASTY indeed.
Do not do this to your ears 8^(
JMHO FWIWDanL
BTW I have all the software to calculate changes
needed in the circuit for 1000V operation.
Email me off-board if you want help with this.
Hi Dan> So 15 watts in A1.
yes> If you only need 10W then why go A2?
I mentioned 10 watts, only as that is what one of tubelab’s graphs showed.I may use one of several different speakers, from some about 99 dB (Lambda, ribbons) ~ for which a 45 would be fine most of the time, to a low of about 86 (Seas) - A2 may at times be quite userful.
If in A2 you really hear the driver and the grid drive, is a tube grid drive feasible, or $$.> > The driver clips before the output stage clips because the 400 volt supply is not high enough.
That’s in his 2nd iteration, not his final design. I understand it’s there to show the evolution of his design.
it’s not just extra power I’m after.tubelab’s “final amp” (3rd iteration), by adding a 2nd“power drive” circuit, raises the point at which distortion is generated in the driver, ie lowers distortion.
> Output stage should clip before the driver stage!!!
Would that be better?, maybe they should both start clipping about the same high point?Yes, I would certainly be interested in Jim’s circuit for 1000 V operation. I wondered what the X1 and some of the values are. When you get a chance, please email me at rick57@optusnet.com.au
Thanks kindly
Richard
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