[Jerrin]

Please do. Having owned the Mono 50s, and having heard the 120s several times at a friends, I can imagine those will be amazing! 

As an update, my amps are slowly making it to the finish line.   I haven't forgotten to share more info on them, but they are still in production.  I agreed with Gary to take his time on them and work on them in between his other orders, so he could ultimately take more time to get them just right.

As for what's in them, I went with Duelund silver wiring, Duelund caps, and Texas Components Tx-2575 everywhere I could throughout the amps.   I'm really excited to see what Gary does with these.   They will provide around 200 watts each.

[nickbojko]

has anybody tried replacing their lead out wires of their capacitors with OCC silver?

[barrows]

re bypassing line level coupling caps.  Many believe use of any bypass caps in the signal path is questionable from a technical perspective.  Two different caps, of differing values, will result in additional time delays, blurring the signal in time.
Most of the time it is probably going to be better to just use the best single cap which one can for the job at hand.

I am still wondering if anyone has tried the Auracap XO for coupling?  Any thoughts vs, say, Mundorf Supreme?  The Auracap XO is nice and compact as well, a plus in my thinking.

[DaveC113]

re bypassing line level coupling caps.  Many believe use of any bypass caps in the signal path is questionable from a technical perspective.  Two different caps, of differing values, will result in additional time delays, blurring the signal in time.
Most of the time it is probably going to be better to just use the best single cap which one can for the job at hand.

In theory I agree... that can certainly happen. I'd prefer to use one high quality cap over a bypassing an inferior cap, but that's not practical in many circumstances. It's very common to parallel caps in a power supply, if you need more than a couple hundred uF the prices of film caps get way up there, as does the size of the cap. I have also heard significant improvements in the cathode bypass caps on my power tubes. In that position you need a large electrolytic cap and I used a Clarity film cap to bypass the electrolytic, which was a great improvement. It's not easy to use electrolytic caps without degrading the sound, but if you have to use one I believe it is always best to bypass it with a film cap to minimize the damage. I have never tried bypassing signal coupling caps, that's one application where I could see the disadvantages becoming audible... but they are usually small value caps anyway.

Also, I consider the last stage of the PS filter and cathode bypass caps in the signal path, but are not dc-blocking coupling caps.

[Ric Schultz]

Many people believe lots of things.  I want to BE LIVE.  The only way to know if something is better or not is to experiment and listen on a seriously tweak system, not quote others who "believe" something.  My direct experience tells me that bypassing is really a necessity.  I have never heard a very large cap (1uf or more) that had really great extended highs.  Audio Research bypasses their exotic custom large Teflon caps with smaller values.  They do this because they listen.  A friend just bypassed his Clarity Cap MRs in his speaker with the inexpensive Vishay Roderstein .01s and .1s and says it made a serious improvement.  Audio tweaking is an art.  Certainly you must listen to different combos of caps and all properly burned in, oriented and damped.  All film caps need to be marked for outside foil and oriented so the outside foil is to ground or to the output.  This makes a noticeable improvement.  Also all caps should be damped....ie not dangling in the air....and all long single strand bare wires need to be covered with cotton sleeving to damp them.  All these things are very audible.  A person posted on Audio Asylum that he tried the Vishay Rodersteins as a bypass cap but they sounded seriously bright.  I replied that he probably has them dangling in the air on undamped leads.....he reported back a few days later saying....indeed, I was right...as soon as he damped the caps and wires he now is very happy with the bypasses.  Everything has to be done right!!!!!!  Years ago I modded an Audio Research Preamp that had both Rel-caps and Wondercaps in it.  Audio Research did not know about outside foil then.  So, they just lined all the caps up so the writing was in the same directions for visual coolness.  I removed all the film caps and tested the Rel-caps and marked them for outside foil and put all caps back in, in the electrically correct way (Wonder caps are marked for outside foil via the writing on them)......way frickin better sound.

[Manolo]

I have a pair of V-caps 0.68uf -original vcaps- as interstage coupling caps in my Supratek preamp and was wondering about bypassing them with, say 0.10 to 0.22 uf CU v-caps.... Has anyone tried something like that with their Vcaps?

[driguy]

I have a pair of V-caps 0.68uf -original vcaps- as interstage coupling caps in my Supratek preamp and was wondering about bypassing them with, say 0.10 to 0.22 uf CU v-caps.... Has anyone tried something like that with their Vcaps?

I had the original V-Caps as coupling caps in my amplifiers. I switched to the CuTF coupling caps (.22uF) and used the TuTF caps as a bypass for the last capacitor in the power supply. The CuTF caps (IME) don't really need to be bypassed when used as coupling caps. Of course, yours are larger in value so that may not be your experience. I realize that purchasing a pair of .68uF caps is more money but in overall gain you should be ahead of the game overall. I am not familiar with the schematic of the Supratek but almost any last power supply cap bypassed seems to help quite a bit. I have used Blackgates, Mundorf M-Tube caps and now I use Clarity T-Caps (the last two non-electrolytics) and they all benefited from the bypass cap. I personally am not a fan of bypassing caps in the signal path but that is my preference. Also, a .68 coupling cap seems like a high value but I don't know the circuit. You may be able to back off on the size and reduce the hit on your budget.
I recently finished building a 20b/300b amplifier with the Clarity Caps in the power supply and believe me, the bypass cap on the power supply cap made a significant difference.
Also, if you have not heard what the CuTF caps can do you are in for a treat. You may want to contact Supratek and ask about lowering the value. Some builders will add extra capacitance if there is room and it is not too expensive. The price of a .22 vs. a .68 cap is very high.
Best Regards,
Tony

[Manolo]

Thank you. The stock coupling caps were 1 uf btw, I. Do not know if the circuit would be optimized with much smaller value capacitors.... I was thinking that by bypassing the 0.68 uf caps with the copper Vcaps Some of the better qualities of the latter could be obtained.... But it is an expensive experiment... Just to find out.

[rollo]

Many people believe lots of things.  I want to BE LIVE.  The only way to know if something is better or not is to experiment and listen on a seriously tweak system, not quote others who "believe" something.  My direct experience tells me that bypassing is really a necessity.  I have never heard a very large cap (1uf or more) that had really great extended highs.  Audio Research bypasses their exotic custom large Teflon caps with smaller values.  They do this because they listen.  A friend just bypassed his Clarity Cap MRs in his speaker with the inexpensive Vishay Roderstein .01s and .1s and says it made a serious improvement.  Audio tweaking is an art.  Certainly you must listen to different combos of caps and all properly burned in, oriented and damped.  All film caps need to be marked for outside foil and oriented so the outside foil is to ground or to the output.  This makes a noticeable improvement.  Also all caps should be damped....ie not dangling in the air....and all long single strand bare wires need to be covered with cotton sleeving to damp them.  All these things are very audible.  A person posted on Audio Asylum that he tried the Vishay Rodersteins as a bypass cap but they sounded seriously bright.  I replied that he probably has them dangling in the air on undamped leads.....he reported back a few days later saying....indeed, I was right...as soon as he damped the caps and wires he now is very happy with the bypasses.  Everything has to be done right!!!!!!  Years ago I modded an Audio Research Preamp that had both Rel-caps and Wondercaps in it.  Audio Research did not know about outside foil then.  So, they just lined all the caps up so the writing was in the same directions for visual coolness.  I removed all the film caps and tested the Rel-caps and marked them for outside foil and put all caps back in, in the electrically correct way (Wonder caps are marked for outside foil via the writing on them)......way frickin better sound.

  Excellent information Sir. My Consonance 211s use V-cap TIO. I thought a bit bright sounding. Went back in damped the leads with compressed wool in lieu of cotton and very pleased with results. No longer bright. I had the caps hot glued. Removed glue and then secured to a nylon base with compressed wool over the cap. To my ears a major improvement. BTW the bases used are Pon-tune footer bases.  We also like 3/8" th. Ebony for the base and under trannies as well. have fun listening and trying.
     As an aside replaced Cardas output coupling caps in the Arion Class "D" amps with Duelund CAST [ copper]. Man they took forever to break in. Stopped changing with over 600 hours on them. Anyone else experience a long break in time with the CAST ? BTW no going back they are the cap for that amp.


charles
     

[ngchaisoon]

  Excellent information Sir. My Consonance 211s use V-cap TIO. I thought a bit bright sounding. Went back in damped the leads with compressed wool in lieu of cotton and very pleased with results. No longer bright. I had the caps hot glued. Removed glue and then secured to a nylon base with compressed wool over the cap. To my ears a major improvement. BTW the bases used are Pon-tune footer bases.  We also like 3/8" th. Ebony for the base and under trannies as well. have fun listening and trying.
     As an aside replaced Cardas output coupling caps in the Arion Class "D" amps with Duelund CAST [ copper]. Man they took forever to break in. Stopped changing with over 600 hours on them. Anyone else experience a long break in time with the CAST ? BTW no going back they are the cap for that amp.


charles
     

I am using Duelund Cast DC (copper) 0.33uf at the output of Altmann Attraction DAC. The first 450 to 500 hours is like a roller coaster ride, sometimes good and sometimes bad. Even when good its lacking in emotion in the human voice. After that its more stable and improving with each listening session. Till now I think I had about 650 hours on them and feels that they are still improving.

Ng

[WireNut]

Without owning an oscilloscope, how would you determine what side the outer foil is on?
Is there some type of gizmo to build or purchase that can identify the outer foil side?

[Speedskater]

Do you have a sensitive capacitance meter?
I never tried this but it might work.
Wrap some conductive foil around the cap. Connect one probe to the foil and the other probe to one cap lead. The lead with the higher reading should be the outer plate, I think.

[andyr]

Do you have a sensitive capacitance meter?
I never tried this but it might work.
Wrap some conductive foil around the cap. Connect one probe to the foil and the other probe to one cap lead. The lead with the higher reading should be the outer plate, I think.

That's a very novel idea - I reckon it should work (if you have a sensitive cap meter - which I do, a Peak Atlas LCR40).  So I will have to try it out.

Well done for some out-of-the-box thinking.   

EDIT:  After I got home tonight, I did the test.  I wrapped some thin aluminium foil around a 1uF film cap, attached one lead of my Peak meter to this ... and then attached the other lead to one cap lead and then the other.

One lead measured 36.8pF ... the other measured 76.8pF!!    So I would assume the latter is the lead connected to the outermost foil? 

And please remind me, where is the outer shield supposed to be connected to:
* on an input coupling cap (shield to the input RCA pin ... or vv?), and
* on an output coupling cap (so, shield to the PCB?).


Regards,

Andy

[Speedskater]

Andy, I answered your easy question, so now you ask a hard one.
The caps outer plate should be connected to the terminal that's closer to ground.
So with an output cap, the active device is only a few hundred (or less) Ohms above ground, so that's where you connect the outer plate.
With the input cap, the active device's input is 10k Ohms (or more) above ground, so maybe you might want to connect the outer plate to the input jack.  (I'm not so sure about this)

[andyr]

Andy, I answered your easy question, so now you ask a hard one.
The caps outer plate should be connected to the terminal that's closer to ground.
So with an output cap, the active device is only a few hundred (or less) Ohms above ground, so that's where you connect the outer plate.
With the input cap, the active device's input is 10k Ohms (or more) above ground, so maybe you might want to connect the outer plate to the input jack.  (I'm not so sure about this)

Thanks, ss - now you've jogged my memory, I think you have stated it simply and correctly. 

[DaveC113]

Wow, there's a new standard for high end, high priced caps... A pair of coupling caps is a good bit more than I spent on my entire preamp build, and I have RelCap PCU copper foil coupling caps, Clarity TC series power supply caps, Mills resistors, stepped attenuators, etc...  the .47 uF caps are $1k each, who's going to try them out?

http://www.partsconnexion.com/capacitor_film_duelund_pio_elec_newS.html

[Maritan]

I've been replacing the electrolytic caps in my 10 year old amp (VTL ST-150) and I've been thinking about replacing/ upgrading the coupling caps while I have the amp open. The upgrade path as suggested by the manufacturer is to go with MIT caps.

Right now, the coupling caps between the output tubes (6550C) are Rel Cap PPMF 0.68uF/ 450V (which already is MIT, I believe?). Due to space constraints (absolute max of 21mm Dia X 45 mm Length), I have narrowed down the choices to the following:

1. Jantzen Z-Superior
2. Jantzen Z-Silver
3. Mundorf MCap
4. Mundorf MCap Evo Aluminum/ Oil
5. Mundorf MCap Supreme

My system is pretty neutral and I can hear changes. When I changed the 6SN7 in my preamp, the changes I could hear were very, very clear. I like the sound as it is, but I always want to know if I'm missing something...    Audio nervosa at its finest. My plan is to change out the capacitors (if you guys feel that it might be worth it), but keep the originals just in case I don't like the sound (after burn in, of course).

Are any of the ones listed above considered an upgrade over the existing Rel Cap PPMF coupling capacitor in the amp? If so, what would your choice be? If you have any other recommendations that fit with the ratings and size limitations, please feel free to recommend them.

[WireNut]

If you have any other recommendations that fit with the ratings and size limitations, please feel free to recommend them.

Hi Maritan,

V-cap OIMP's, Auricap, Sonicap, and AudioCap Theta's should fit the same space as MultiCaps or Rel-caps.

You may want to double check the sizes on the Jantzen Z-Superior, Z-Silver and Mundorf Supreme's. I pretty sure those are a lot bigger than Multicaps or Rel-caps.


 

[Russtafarian]

I have narrowed down the choices to the following:

1. Jantzen Z-Superior
2. Jantzen Z-Silver

The Z-Superior has been my cap of choice for the last few years.  To my ears it strikes the right balance between articulation and musical flow.  I use them as coupling caps in my Sony ES preamp and Quicksilver monoblocks.  I also have them in my tweeter XO (bypassed with a small Sprague PIO).  It's about 1/4th the price of caps with competing sound quality.  Given that your VTL requires one cap per output tube, the price of any cap you choose adds up pretty quickly.

On the other hand, the more expensive Z-Silver sucks.  Makes everything sound like a buzzsaw.

Another cap to consider is the Clarity MR.  If you're looking to maximize resolution and transparency, it will take you further than the Z-Superior without getting too analytical.  It's also 4X the price of the Z-Sup and 3x the size.  Make sure they'll fit under the hood before pulling the trigger on these.

Also, if you can get hold of a cable cooker and run your new caps for a week before installing them, your amp will get up to sound much quicker and save your vacuum tubes from a lot of break-in hours.

Russ

[avahifi]

So, I am working on a new RIAA phono preamplifier.  It is doing very well, easily outperforming most others we have heard here at rational prices.

It is DC coupled from input to output so I have no coupling capacitors to worry about at all.

However there are two capacitors to ground in passive filter circuits.  One needs to be 0.15uF/50V and the other either 0.015uF/50V or possibly 0.0082uF/50V depending upon the impedance we want for that part of the second passive filter.  We know we have overkill drive current to charge and discharge these parts without stressing the active devices.

The capacitors must be physically small, none microphonic, none inductive, free of thermal drift, and available at tight and consistent tolerances at rational prices.  There seem to be two recommended choices of parts type, either polypropylene or COG ceramic.  Audio Precision seems to suggest NPO/COG ceramics as a superior choice.

Any suggestions or recommendations around here?

Thanks,

Frank Van Alstine