[seraph321]

Weeze, thanks for the advice, but I'm afraid you lost me a bit there. Are you saying that if I run my source (SB2 analog) into a tube preamp that actually has dual-ouputs built-in (the modwright) and feed that to two SS amps (the carver and gallo) that I could potentially have freq roll-off problems? That seems awfully strange to me.

It seems like I would have more issues with splitting a single source and running the high freqs through a tube preamp, but sending the low freqs directly through a ss bass amp. Mainly because it seems like it would be a pain to match output levels, but I have little-to-no experience thinking about the varying impedance issues being discussed here.

[WEEZ]

Yes, it's possible. And as Steve wrote, the capacitance might be an issue also.

If you use a preamp to drive (2) amplifiers, the preamp sees a load that is half.(if both amplifiers have the same input impedence)

(input z of amp 1 x input z of amp 2 divided by the sum of both impedences)

I'm not saying it's an issue...I'm saying it might be. 

As for your second scenario, I think it would be difficult to match the gain. How robust is the output stage of the SB2? If it's like most digital equipment, it might have a problem with the load that IT sees.

WEEZ

[Steve]

Weez is right on. The input Z of the two amps are in parallel and the capacitances at high frequencies could cause alot of problems, cause they are additive.

With SS, the input capacitance could vary substantially, depending on the input SS device part, Vcc+ voltage present, and signal strength.

For instance an IRF 820 will substantially change junction capacitances until around +25 volts on the drain. So as the drain voltage changes with signal, from 25 and less, the junction capacitances continually changes. This means the miller capacitance changes throughout the waveform.

But as Weez mentions, it may not pose a problem.

[WEEZ]

(thanks for the technical help, Steve  )

WEEZ 

 

[seasterl]

This may sound profound, but being a tube guy, I'm not interested in "transparency" so much as I'm interested in "realism."  To me, tubes sound more realistic.  Whichever combination of gear convinces me the most that Count Basie or Norah Jones or Sarah Vaugh, etc. is actually in the room singing to me and drawing me in emotionally so much I can't even read my favorite magazine,... that's what I call realism and that's what I'm after.  Transparency, yeah, there's a place for it and we tip our hat to it, but it's more for recording engineers, I think.  Don't get me wrong, but I don't like it any more than the next guy when I try a piece of equipment and it sounds veiled and terribly colored to the point that the instrument does not sound like it does in real life.  There's nothing wrong with tonal balance to the point that it affects the midrange and makes the music more laid back (and this is how I enjoy my tubes), but the right tube combo that makes the music more realistic and convincing is the best for me.  I had an ultra pure Class A SS system that took the enjoyment out of many of my lesser recordings due to being too revealing, but somehow (and I'm not sure how) my tubed gear makes all of my recordings enjoyable and still not sacrifice detail.

[DSK]

FWIW I ran RCA Y-connectors on the analog outputs of a Bolder modded SB2 (analog & digital mods, Bolder Deluxe PS) to directly feed an SS amp (47k Zin) and active servo subwoofer (~35k Zin) with no apparent problems over a 6 month period. Before doing so, I checked with SlimDevices and modders who said it would be fine and that the SB can drive a 5k load. This was despite the fact that the Bolder mods remove the opamp, reducing the output to approx only 1V.

More recently, I tried the SB2 through my tube hybrid pre-amp which has an output pair directly off the SS section for the sub and another off the tube output stage for the main speakers. Performance improved with more body, more dynamics, quieter background, more natural sound. This is how my system will stay for now.

[WEEZ]

seasterl,

I know exactly what you mean. Your system is likely more transparent than you admit.....it's how one defines it....

DSK,

Cool. A system with a pre-amp usually works better than one without. (Usually..)

WEEZ

[Steve]

I want it all, ultra transparency, and realism, live voices and instruments. I want to be able to see the individuals; to be sitting right in front of them as they sing and play instruments. I want to hear the reflections off the recording studio walls, to experience being there.

To me, that is what neutrality and accuracy is all about. I don't want sterile or bloated images, or fat thumping bass, or exaggerated highs that aren't accurate.

I want it all baby! 

[95bcwh]

I want it all, ultra transparency, and realism, live voices and instruments. I want to be able to see the individuals; to be sitting right in front of them as they sing and play instruments. I want to hear the reflections off the recording studio walls, to experience being there.

To me, that is what neutrality and accuracy is all about. I don't want sterile or bloated images, or fat thumping bass, or exaggerated highs that aren't accurate.

I want it all baby! 

And what preamp/amp combo do you know of can give you that "perfect" sound??

[Steve]

I can think of a three excellent systems. Marcus's system, Rich Weiner's system and I am currently auditioning a pair of Rick Craig's phast jr. speakers, have approx 70 total hours on them. They are all excellent, with just very slightly different strengths and weaknesses.

Marcus's system is slightly stronger in the attack with excellent intimacy yet with some reflections off the recording studio walls, and a little more bass. Rich Weiner's system playing a violin solo is something to behold (He likes that kind of music). He also hears the recording studio wall reflections in recordings. I also hear those reflections as well with the  strength of great soundstaging, and only very slightly weaker attack times with Marcus's system, and slightly weaker bass, which I am trying to correct.

All three systems use different components, but all accomplish close to the same things, just very slightly weaker and stronger in different areas. Marcus uses solid state amps while Rich and I use tube amplification. All three systems use tube preamplification.

Inner harmonic structures, the "flesh" on all three are fabulous, yet open sounding.

Still I am striving for even more perfection, that last little bit of musical realism.

Cheers 

[95bcwh]

Oh interesting.. can you tell me the exact name of the equipment they used? I should probably put all of  them under my audition list..

I can think of a three excellent systems. Marcus's system, Rich Weiner's system and I am currently auditioning a pair of Rick Craig's phast jr. speakers, have approx 70 total hours on them. They are all excellent, with just very slightly different strengths and weaknesses.

[Steve]

I can't remember all the details, components, so you might contact the individuals listed.

Rich Weiner (Bound for Sound)

Earlmarc

Take care.

[WEEZ]

Steve,

Normally, I don't like the looks of 'silver' components...but I have to admit, that the pics of your 11A in silver look killer. Is this a new 'look' for all the pre-amps ?- or just the 11A?

I like the elimination of the rack slots....

Just curious 

WEEZ

[PromitheusAudio]

Sorry for jumping abit late on this.

Tube sound and transparency can coexist very well by the design topology and the choice of components

I found that if I design an amplifer around an interstage transformer whether single ended or pushpull it will have this really natural transparency. Some how the music is musically and fluid but at the same time have PRAT, transparency and airy highs.
The choice of components is just to tilted the balanced to more musically or more transparent depending on the users requirement

In short the topology and design is the most critical to give you the valve sound with transparency. I know this because i have been making amps this way for a while.

[Steve]

Hi Weez,

     The picture could probably have been better, the 11A is gold/brass. I have been toying with an optional silver for the 10A.

Take care.

Steve,

Normally, I don't like the looks of 'silver' components...but I have to admit, that the pics of your 11A in silver look killer. Is this a new 'look' for all the pre-amps ?- or just the 11A?

I like the elimination of the rack slots....

Just curious 

WEEZ

[Sasha]

Yes, it is called Linar amplifier.

[audioengr]

I'll jump in too, since I now have a tube gear of my own.

It is no surprise to me that the same mods that make SS sound dynamic and extended also work on tube circuits.  It is all about power delivery to the active devices, tubes in this case.  Most tube designers, like SS designers do not have a good grasp of this.  Because tubes use high-voltages and the currents are very small, this makes tube design easier, particularly when it comes to power delivery.  As a result most designers who learn from other designers make the same errors and this keeps propagating, namely star-grounding schemes that dont work, cabling from the power supplies that is poor, poor selection of capacitors and usually no decoupling caps.  If all of these things are done correctly, you would be surprised at how close tubes sound to excellent SS, particularly in the HF extension and dynamics.

Steve N.