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Old 14th May 2006, 04:19 PM   #1
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Default New Ec8010-vt52 Amp

What do you thin about my new amplifier?
It is Valvo EC8010 with a russian teflon capacitor to Hytron VT52 to Lundahl 1623 transformer (5600ohm to 8ohm).
It work well; it is only a little noisy so I will change the BlacKgate 47+47uf (one 47uf for each channel) to a new Blackgate 100+100uf 500V that I have ordered from Part Connection-Usa.
From the first test it seem that my old (Loftin White direct coupled kind) E83CC+VT52+Lundahl (3000ohm to 8 ohm) with hexfred diodes rectifiers has more wide stage and more brillant presence. But I am not so sure. I need more tests.
Gian Luca

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Old 14th May 2006, 05:16 PM   #2
Giaime is offline Giaime  Italy
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So beautiful tubes and so simple driver stage?

Go totem!
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Old 14th May 2006, 05:44 PM   #3
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Default another VT52 amp - my first diy amp

This was my older amplifier, a Loftin White kind.
It is another single ended triode amp with a simple driver, with more gain than ec8010. Ultra bass and high tone, real concert performance with my Tannoy Edinburgh HE loudspeakers.
Anyway I think that with set class A amp simpler is better. Try to listen John Coltrane sax, Arturo Benedetti Michelangeli piano, YoYoMa cello or Elvin Jones drums with an amplifier of this kind and you will undesrstand what I mean.
What amplifier kind do you use? If you are using a set amp what driver you prefer and use?
Gian Luca


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Old 14th May 2006, 05:56 PM   #4
Giaime is offline Giaime  Italy
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Hello Gianluca,

I'm not using SET amps right now, I'm designing a PP amp.

The reason that you might like "simple is better" approach when driving an SE triode, is, in my modest opinion, the result of harmonic cancellation between the driver and the power stage.

It's obvious that a more linear driver approach could give you less harmonic cancellation so higher total distortion, anyway I think that if you properly design the output stage, you don't have to care about that, and simply go for an higher performance driver.

That's only my opinion, of course
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Old 14th May 2006, 06:08 PM   #5
kevinkr is offline kevinkr  United States
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Hi Gianluca,
A single section choke input filter with input cap is going to produce a considerable amount of ripple. I would recommend adding an additional choke of say 8 - 15H and another capacitor.

Shizuki/ASC motor run caps are great for this, sound good and cost much less than the Black Gate..

Another technique you can use to reduce the output noise if it is predominantly from supply ripple would be to add a film cap between the B+ supply to the output transformer and the cathode common point (your 100uF bypass cap) Select this cap based on the ratio 100uF/mu+1 - in practice something like a 22uF cap will work fine. I use this in one of my amplifiers with great success.

I think WE did something similar in some of their early amplifier designs, it does not work quite the same way as the "Ultrapath" connection as it forms a capacitive voltage divider for the ripple voltage on the supply. Done properly the ripple on the plate is almost cancelled. (As are presumably the ripple voltage induced plate current variations which result in ripple on the secondary of your output transformer. Whatever, it does seem to work well.)

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Old 14th May 2006, 06:32 PM   #6
Zen Mod is offline Zen Mod  Serbia
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Gianluca-beautiful amp!

where you found EC8010 and what's the price?
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Old 14th May 2006, 07:02 PM   #7
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Default Re: New Ec8010-vt52 Amp

Nice amp. The EC8010 i hear is almost made of unobtainium...

Quote:
Originally posted by gianluca
Part Connection-Usa.
Parts Connexion is in Canada.

dave
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Old 14th May 2006, 08:54 PM   #8
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To Kevin:
I will try to reduce the hum from the actual 25mV rms to less than 7-8mV (with 147uF).
Thank for your infos. I will try also your suggestion: The problem was that I wasnt able to install three chokes on my chassis, so I listened a Gordon Rankin suggestion: he said me that it was better to use tho parallel chokes one for each channel to separate them than to use two in series as I thought before. So now I have better separation but a little noisy amplifier.

To Choky:
I bought 6 nos Valvo EC8010 two months ago on Ebay; I bought another one that should be nos but really doesnt work.
I paid nr.6 Valvo EC8010 162 euro.
I had 4 Raytheon 5842 but after reading your, Choky, opinion on Audio Asylum about the EC8010 I preferred to try them.
What do you think about the polarization that I used on EC8010?

I am happy that you like my home made amp.

Gian Luca Cazzola
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Old 14th May 2006, 08:54 PM   #9
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Default to Dave

Ok about Parts Connections in Canada.
About Ec8010 I have seen some of the on Ebay in the last months and the price wasnt higher than 20 euros each - sometime even less.
Gian Luca
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Old 14th May 2006, 09:16 PM   #10
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by gianluca


To Choky:
I bought 6 nos Valvo EC8010 two months ago on Ebay; I bought another one that should be nos but really doesnt work.
I paid nr.6 Valvo EC8010 162 euro.
I had 4 Raytheon 5842 but after reading your, Choky, opinion on Audio Asylum about the EC8010 I preferred to try them.
What do you think about the polarization that I used on EC8010?

I am happy that you like my home made amp.

Gian Luca Cazzola

tnx for quoting the price-it's just for reference ;

Audio Asylum? I forget when I last time was been there.....in fact-complicated board,and I really have no much energy to wrestle with this sort of issues-because I'm on the net when I really need to sleep

polarization is OK with me -if is OK with you
I'll ,in your boots,hit the critter with more current and smaller Ra.......say 5K6 for Ra and some 3W of dissipation (around 17-20mA.....you can look on my www how I make this........
anyway-try and decide what you like more
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