lionelag
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Maybe I'm a tube guy after all...
smejias
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Heh heh. Very cool!
I share your enthusiasm for Espers, by the way.

mikeymad
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now if we can all be so lucky to have our own systems excite us... It has been a little while for me....

Cheers,

lionelag
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Quote:
Heh heh. Very cool!
I share your enthusiasm for Espers, by the way.

My next bit of geekiness will be trying to fix the output impedance imbalance-- there are a pair of 510k resistors on the output jacks of the PAS that I suspect are killing what little bass response that it has in combination with my solid-state Rotel. But I got almost weepy last night listening to FM radio(!). The sound was that good.

Somehow I've never seen the Espers live, even though they're local, but their two original albums are brilliant and the EP of covers is as great as it is unexpected. (Who would have thought that a folk group could cover Blue Oyster Cult's Flaming Telepaths and make it work?) And, like I said, the recording quality of all three of their CDs is demonstration quality. (Haven't heard the vinyl, but I imagine it's just as good-- Drag City presses good vinyl.)

Greg Weeks, one of the Espers, produced a similar-genred act called Ex Reverie who are also really good-- their only album so far came out in April or May of this year. Espersish, but a bit darker-toned.

dorokusai
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I've never been a huge Dynaco fan but I respect the heritage. You can however, count me in for vintage Conrad Johnson or Altec any day

You're right, folks like original...me? I could care less. If I never see another barrier strip speaker termination, it will be too soon.

That's a great story Lionel. I'm a tube pre-amp fan and wouldn't have it any other way. I came close to the tone I wanted with a NAIM pre-amp but I thnk I'll stick with tubes. What are you running inside of it? I may have some modest recommendations for drivers if you're interested in rolling. Either way, enjoy!

Mark

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If the unit had the original tubes in it, those would be Telefunken Diamond bottom 12AX7A's. Near impossible to beat, sonically, in the entire timeperiod of 12AX7's that have ever been made.

As for the Dynaco's..I've rebuilt (redesigned) the power supplies (10x the energy storage and 'flow'), rewired them...and cut out the tone controls, completely.

I've done similar to SCA-35's (the EL-84 integrated) which is an AWESOME unit, properly modded. Frighteningly good.

For me, it's tube preamps all the way, baby! Then a little SS power or hybrid power.

I'm about to get into some of Peter McAlister's 'Sweep tube' monoblocks.

here's the interesting part.

A standard power output tube has the ability to handle a certain amount of voltage and current. The two figures (together) are it's overall 'power dissipation' value.

Let's say, 500V..with 100ma. That's a generously huge figure.

Now, Sweep tubes, or 'horizontal output tubes'..are, for the most part (99% or better) capable of far more current and voltage.

Let's say..7000 (that right, 5-6-7-8 thousand volts!) volts is the maximum level..and then... also 1 AMP of current capacity. That's a HUGE difference, in the capacity of the tube itself.

But the benefit does not stop there. Sweep tubes are MORE LINEAR..and with lower internal complex impedance issues. They are also built to NEVER deviate and to work in a perfectly linear state, under extreme conditions and duress..and long, long time periods.

What this ends up meaning is that the usual tube output transformers are not even remotely capable of taking the capacity of sweep tubes to their utmost beneficial level of service to music reproduction.

This means that the transformers must be hand wound or made totally differently, which no-one does. Peter makes his own transformers, BY HAND. Himself. Each one is hand made and done in ways that others do not pursue, as it is far too expensive to make a transformer that way.

The important bit, is that the sonics of a tube amp can be and ARE limited by the characteristics of the transformer.

With 10 times as much current available,and with much higher voltage capacity..this means much more energy available and more linear, to boot...that Peter can make a tube and transformer combination that outperforms all others that came before..as he can reduce the 'winding mass' in the transformers..which has all kinds of benefits.

This is why there is a waiting list for McAlister audio products. And the price is...so low...

lionelag
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Quote:
I've never been a huge Dynaco fan but I respect the heritage. You can however, count me in for vintage Conrad Johnson or Altec any day

You're right, folks like original...me? I could care less. If I never see another barrier strip speaker termination, it will be too soon.

That's a great story Lionel. I'm a tube pre-amp fan and wouldn't have it any other way. I came close to the tone I wanted with a NAIM pre-amp but I thnk I'll stick with tubes. What are you running inside of it? I may have some modest recommendations for drivers if you're interested in rolling. Either way, enjoy!

Mark

Well, the Dynaco speakers were all designed by SEAS, anyway. Their only real fault is the fact that silk-dome tweeters in those days would only go out to about 12.5-13khz, which is a limitation that makes them sound a little dull on the high end. SEAS makes a drop-in replacement which is rated out to something like 30khz. Conrad Johnson stuff is always out of my price bracket-- even the used, 70s stuff. (The preamp that Sam Tellig recently reviewed as "reasonably priced" costs more than I paid for my current car. So much for the Audio Cheapskate...) I'm not all that familiar with Altec's hi-fi speakers, but their guitar amp speakers were some of the best ever made, so I imagine they're worth keeping an eye out for.

Sadly, this PAS doesn't have the original Telefunkens. It has a brand-new, perfectly decent set of Russian Electro-Harmonix 12AX7s. A set of Telefunkens would cost more than what I paid for the preamp. I'm not set to do any tube-rolling until I decide whether I'm going to keep the Dynaco boards inside. (Curcio uses 6922s, and I think Van Alstine is using 6N1Ps at this point. We all know a certain person's predilection for Van Alstine, but does anyone know anything about Curcio's upgrade boards? His prices are quite reasonable, and I like that he provides schematics.) I don't have any tube measuring equipment, so I can't even attempt to match the fair number of 12AX7s I have left over from various guitar amp projects. (Including, IIRC, a couple of Mullards that were sitting in an early 60's practice amp and which I replaced because they wouldn't distort easily enough. )

Lionel

lionelag
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Quote:
As for the Dynaco's..I've rebuilt (redesigned) the power supplies (10x the energy storage and 'flow'), rewired them...and cut out the tone controls, completely.

Yeah. The one I've got has the tone controls cut out of the circuit. I have crazy ambitions about changing the knobs to bass and treble turnover knobs and actually putting the "tape head" and "special" settings to actual use (I own a fair number of ffrr mono LPs that I inherited from my grandmother and/or liberated from my father's library) but I could care less about tone controls.


Quote:

But the benefit does not stop there. Sweep tubes are MORE LINEAR..and with lower internal complex impedance issues. They are also built to NEVER deviate and to work in a perfectly linear state, under extreme conditions and duress..and long, long time periods.

What this ends up meaning is that the usual tube output transformers are not even remotely capable of taking the capacity of sweep tubes to their utmost beneficial level of service to music reproduction.

This means that the transformers must be hand wound or made totally differently, which no-one does. Peter makes his own transformers, BY HAND. Himself. Each one is hand made and done in ways that others do not pursue, as it is far too expensive to make a transformer that way.

The Plitron guys up in Canada make some very interesting custom trannies, too. (I've been drooling over one of the toroidal output trannies they make for EL84 guitar amps, but haven't been able to justify the price to myself yet. Maybe after I get another band together) It certainly seems like the biggest limitation in tube technology has always been the transformers. (Some of the radio transmitter and telephone repeater tubes were capable of thousands of watts. And they're cool looking too-- the same people who go in for giant 845 and 300B tubes would go nuts if someone came up with a tube amp based around say, a 9c21...)

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