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Old 9th March 2007, 02:44 AM   #161
Ipanema is offline Ipanema  Malaysia
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stereo
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Old 9th March 2007, 02:46 AM   #162
Ipanema is offline Ipanema  Malaysia
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Flat8A
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Old 9th March 2007, 07:03 AM   #163
Vix is offline Vix  Yugoslavia
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I wouldn't say that what you describe is a merit of a second harmonic.

Some speakers sound better with a higher out impedance amplifiers. They gain more top and bottom end. Also, to my ears, no feedback amps tend to sound more "airy" and relaxed.
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Old 25th March 2007, 02:04 PM   #164
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wow

and here it is, worked straight away(phew)....
took it to a local meet yesterday which was a bit of a risk because I hadn't even listened at that point...it held its own in some very esteemed company and got some v.good comments from the valve(I hate ss) guys.

I will post my thoughts after listening over the next few days..

at the moment 3 of the 4 transistors run at 63 degs after 1 hour and 1 of them seems to like it at 72 degs...I'm thinking I might tighten the bolt on that 1 as a first step...the sink runs at a constant 38 degs. With nothing connected at input its inky black into my vofos(see my web site)

Its slightly more sensitive than my EL34 SE but I think already outshines it for exposing detail....early days!!


many thanks to Nelson.

Regards

Ed
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Old 26th March 2007, 07:19 PM   #165
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Looks great.

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Old 26th March 2007, 08:23 PM   #166
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Hello,
I'm interested in this fantastic amp but I'm not expert in this kind of amplifiers.
Only one question: 18+18 V-100VA transformer is too small for a single channel of F2?
Thanks
Guglielmo
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Old 26th March 2007, 10:31 PM   #167
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Yes, it's too small.
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Old 28th March 2007, 05:55 PM   #168
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I've got a bit of a buzz on one channel which is driving me nuts and I wonder if anyone might have a guess at what might be amiss.

It won't measure on the DMM (< 1mv)and it probably wouldnt be visible with less efficient speakers. Its quiet with nothing in the phono, loud when shorted and in the middle when it has a source connected.

I think I'm looking at PS ripple here but would like some confirmation and any guesses as to why one channel should be louder than the other......the scope is set 1mv at 1ms..measuring output.


Regards

Ed
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Old 28th March 2007, 07:16 PM   #169
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by vitalstates
I've got a bit of a buzz on one channel which is driving me nuts and I wonder if anyone might have a guess at what might be amiss.

It won't measure on the DMM (< 1mv)and it probably wouldnt be visible with less efficient speakers. Its quiet with nothing in the phono, loud when shorted and in the middle when it has a source connected.

I think I'm looking at PS ripple here but would like some confirmation and any guesses as to why one channel should be louder than the other......the scope is set 1mv at 1ms..measuring output.


Regards

Ed

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Old 28th March 2007, 10:02 PM   #170
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Hi Zen

I've been scratching my head over this....I thought GL as well but can't figure out how.......I checked the cold resistance on the thermistors as I thought that could be the only path....one measured 14.8 ohms and the other 14.4 ohms..I then discounted it at the time cos the voltage across chassis and circuit ground was identical on both channels.

Do you think that might be it??? Do those cl60s normally vary so much??

Ed
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