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Old 4th July 2012, 06:13 AM   #41
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I know that the word "warmth" has been used a lot about tubes. I don't see it that way. Yes, you'd get a "warm" sound from tubes like 12AX7 and 6SL7 for instance, but that's not what I'm after at all. I use only DHTs including all the small tubes like 26, and if I were looking for a generic word it would be some combination of "vivid, sparkling, detailed, transparent, dynamic, full of life...". Gingertube uses the words "cold, sterile, boring" of SS equipment, and "lively, vivid" is certainly the opposite of that.

I know this discussion is a bit off topic since the OP wants to use his ECC88s, but if he were to "add" something to an F5 I'd suggest that an alternative down the DHT route would be "sparkle and life".

andy

Last edited by andyjevans; 4th July 2012 at 06:17 AM.
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Old 4th July 2012, 06:19 AM   #42
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Nelson Bass,
Interesting - my power amp (a Baby Huey) output stage is as about as balanced as it is possible to be. The design incorporates a forced symmetry function. I'm about to embark on a new preamp build, I had some conversation with Allen a few months before his untimely end, and he provided me with a "Commercial In Confidence" copy of the SVP2 circuit (the most recent FVP5 variant) and that is what I'm proposing to build. I have considered going something simpler such as SY's offerring. I tend to agree that the "wire with gain" sound is appropriate up to the power amp but have never been happy with power amps with that "philosophy". I have a Hugh Dean SS Power Amp like that and find it needs a tube buffer ahead of it. The power amp I absolutely loathed and could'nt listen to was a top of the line 210W per channel ROTEL (SS) with 0.0001% THD specs ( I sold it within a month of getting it). It went to a guy who bridged the outputs for 400Watts and hooked it up to a Line6 DSP Guitar preamp, that is, it was used for reproducing distortion at ear bleeding levels, I thought that was poetic justice.

This whole thing of-course depends upon where in the spectrum from a "Piece of Wire with gain" through to a "Musical Instrument in its own right" your preferrences lies.

I've has amps at either end of the spectrum (that ROTEL at one end and an rather sickly sweet 845 SET at the other end) and now I'm a firm fence sitter, right in the middle.

Andy,
I have a small stash of mesh plate 26 tubes - perhaps I should look at that.

Formula 22,
Apologies for filling your thread. I guess what we are saying is that if you are happy with that sound then go for it. You may find as many of us do that your tastes change with time and all you can do is build something else and try that too. For the SY offering I referred too above, search "Heretical Preamp" on this forum. It is another ECC88 design.

Cheers,
Ian

Last edited by gingertube; 4th July 2012 at 06:32 AM.
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Old 4th July 2012, 07:02 AM   #43
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Ian -

Mesh plate 26????

Do you mean 27?

Andy
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Old 4th July 2012, 10:44 AM   #44
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The nice thing about the FVP5 is that you can switch to different input tubes to "tune" thge4 preamp to whatever sound you like. You could even use a DHT as the front end. The output just pushes the signal out in as transparent way as possible. The FVP5 has to much gain with a ECC88 in the front end.

I think the essential difference between the tube sound and the "clinical" SS sound is the effects of large amounts of gNFB which robs the sound of all life. Tubes with no or low feedback preserve the life in the music. My latest preamplifier has 5687's - no feedback and an output transformer which helps reduce gain to usable levels. It is trhe cleanest and most detailed preamplifier I have heard and yet has spade loads of tube induced presence and life.

Shoog
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Old 4th July 2012, 10:54 AM   #45
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man, some really brave statements about tube sound here
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Old 4th July 2012, 01:44 PM   #46
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Quote:
Originally Posted by tinitus View Post
man, some really brave statements about tube sound here
We're fearless - we play with high voltages.....
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Old 4th July 2012, 03:06 PM   #47
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Question FVP5 pramplifier - schematic?

Quote:
Originally Posted by Shoog View Post
You have one of the finest cleanest sounding amplifiers out there - in the form of the F5. I say learn to appreciate these outstanding qualities and build a preamp which preserves them.
My first option would be one of Allen Wrights designs in the form of the FVP5, or one of the later incarnations. That would be one of the best sounding - purest designs available and relatively easy to build if you restrict yourself to the Line stage component and don't include the superregulator.

Shoog
I agree with you, just insert here the schematic (circuit or project) of the preamplifier.
Or where on the net can be found?
thank you!
P.S.
Otherwise, I tried this a preamplifier with ECC88 Philips Mini Watt and you say sounds good investment!

Last edited by formula 22; 4th July 2012 at 03:19 PM.
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Old 4th July 2012, 03:37 PM   #48
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The top schematic on this page;

Schematics

Everything to the right is the line stage - everything to the left is the phono preamplifier.

A well filtered linear power supply will substitute for the superreg - shoot for about B+ of 240V DC.

Shoog
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Old 5th July 2012, 06:49 PM   #49
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Default Total Harmonic Distortion Graph of PP-1C

Hi Shoog!
Such distortion THD I want to get around the preamplifier, but with higher 2H> 0.5%. (as in this amplifier: Total Harmonic Distortion Graph of PP-1C).
And if you can power supply a few words about the preamp with ECC88,...
thank you
Attached Images
File Type: gif pp_1c_thd_s.gif (10.8 KB, 677 views)

Last edited by formula 22; 5th July 2012 at 06:55 PM.
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Old 5th July 2012, 08:36 PM   #50
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As I suggested before, the preamplifier can be voiced by switching out the front end ECC88 with something else. Think of an old low mu octal valve with a big bloomy sound,which is happy with 100v on its plate.

As for power supply -
6x4
1 to 10uf cap
5 to 10H choke
100 - 300 uf cap

Thats a a good starting point. The circuit has poor power supply noise rejection so you need a very quiet supply - additional stages can be added and final voltage can be tweaked with series resistors. You need to look at the free design software PSU2 to help model a power supply.

Shoog
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