Output Capacitor Upgrading Questions

[Paul Joppa]

There's another theory, which suggests using a small resistor in series with the electrolytic - something around an ohm - and bypassing the combination. The ESL of the electrolytic can resonate with the bypass, and the resistor damps that resonance. Problem is that you need to know the ESL and the bypass capacitance to determine the best resistor value. I don't know anyone who has tried this, but it makes sense to me that a small resonance in the top octave could have bad audible effects. When I get some time I'll see what specs I can find on the Crack output cap.

 

[Laudanum]

This is interesting.   I didnt purchase any caps specifically for bypassing the last PS electrolytic in Crack.  I have a bunch of film caps around but most are very low value or too high of a value that I didnt consider them for bypassing.   So, I experimented with what I had on hand.  One of these was indeed a .01uf audiocap theta (I have a few of these left over, used some as crossover bypass caps).  I also tried the same value Dayton film and foil as well as a 1.0uf Solen or Axon.  I even tried a low value tubular mylar cap.  To be honest,  I really didnt notice any real improvement with any of these caps.  Certianly though, I didnt hear any negatives, just simply perceived no real difference at all.   I wrote this off as maybe the value being too low.  I increased the cap size by going away from the audio caps I had and I finally heard what I perceived as a subtle improvement in when I bypassed with a Panasonic 2.2 or 2.0uF (cant remember which) polyprop film cap.  I attributed this subtle improvement to the caps maybe filtering some high frequency noise.  But again, I attributed it to the larger cap value moreso than the "status" of the cap itself.  I later picked up some larger value Solen and Mundorf caps, around 2 or 2.2 uF with the intent on replacing the panasonic in Crack and using these in other bottlehead kits.  I never got around to replacing the Panny though as it did provide the subtle improvement I mentioned.  I can revist the small value Theta I guess and give it another listen.  However, I have a feeling I may be comparing the Theta to, what effectively amounts to, listening with no bypass cap seeing how my non golden ears heard no difference with the Theta, and those other caps I initially tried.   But prompted by this topic, I may consider experimenting with the PS bypass caps I installed in FPIII and Seduction. I installed a Mundorf MKP in one and a Solen in the other as bypass caps as part of the original build, again, thinking it was probably more of the caps uF value than the cap itself.   Understand ... Im not saying that improvements cant be had with different and/or more expensive caps.  Just saying that I didnt hear that difference with the smaller value caps I tried in Crack.  But again, I think it may be worth some experimenting with FPIII and Seduction since I didnt do any comparative listening in those amps.  Of course, everyones ears and systems are different.  I know that there are a few here that have used basic MKP caps, Solen, Mundorf etc. as bypass caps for the PS electrolytic.  They may very well be hearing positives using these caps instead of the negatives impressions expressed here by Matthew just as he is hearing improvement with .01uf Thetas where I heard no real difference.  Just based on the experimenting I did with Crack, I have to say that the small improvement I noted with the PS bypass cap doesnt compare to the improvement when replacing the lytic output caps with large MKP film caps.  The stock lytics sound good, but replacing with Film caps made for a very nice improvement.  Not earth shattering but a good bit beyond what I would consider "subtle".  To me, it was a much larger difference/imporvement compared to bypassing the PS lytic.  Again, we all have different ears and different systems but I wouldnt write off considering replacing the output lytics with film caps because of positive results achieved with bypassing the PS cap.  I tend to reach the diminishing returns justification "defense" sooner than most others in this hobby but I wouldnt consider being there before upgrading the output caps to films after doing so myself.  It was on my short list based on others results and for me, well worth it.

Of course, just my non tech savvy opinions and YMMV widely.

 

[BNAL]

Right now my intention is to try the 0.22 Russian Teflon caps. I doubt that I would have gone out and bought them, but since I had them lying around I figured I'd give them a try. I want to put Mundorf 100uF MPS caps in to replace the electrolytics.

The only changes I have made at this point is to the power supply. These include a bypass cap and choke. So far these changes seem to have made an improvement to my ears and I think the amp sounds great. I can't imagine that the Speedball can make it that much better.

I will also have to look at doing similar PS upgrades to my Foreplay III, but I have been doing most of my listening with the Crack lately.

 

[Raksasa]

Here's a question for the technically minded:

Is it possible to use Metallised Film caps (polyester or polypropylene) to completely replace polarised electroes in PS caps of an amp like the Crack ?
What would be the PROs & CONs of doing this ? Any actual advantage to the film caps ?

Here's a CON:  Size.

Didn't old low power tube amps use PIO in PS ? They aren't polarised are they ?

Not very practical, but I'm just interested to know.

Cheers,

John

EDIT:  This continues in a new thread in Technical Topics, here: http://www.bottlehead.com/smf/index.php/topic,2614.msg21206.html#msg21206
Pls respond to this query there. Thanks.

 

[earwaxxer]

We are talking about wiring caps in parallel to achieve the bypass right!?

 

[Grainger49]

Here's a question for the technically minded:

Is it possible to use Metallised Film caps (polyester or polypropylene) to completely replace polarised electroes in PS caps of an amp like the Crack ?
What would be the PROs & CONs of doing this ? Any actual advantage to the film caps ?

Here's a CON:  Size.

Didn't old low power tube amps use PIO in PS ? They aren't polarised are they ?

Not very practical, but I'm just interested to know.

Cheers,

John

That is a good question for a thread in Technical Topics.  You just edit your post with a link here.

 

[Paul Joppa]

Here's a question for the technically minded:

Is it possible to use Metallised Film caps (polyester or polypropylene) to completely replace polarised electroes in PS caps of an amp like the Crack ?
What would be the PROs & CONs of doing this ? Any actual advantage to the film caps ?

Here's a CON:  Size.

Didn't old low power tube amps use PIO in PS ? They aren't polarised are they ?

Not very practical, but I'm just interested to know.

Cheers,

John

Yes it is technically possible, and preferable. Film caps are more reliable and have much longer lives, as well as sounding better. Most popular on the forums are so-called "motor run" caps, but other types are available and as long as the ratings are suitable would work well. Because they are large and expensive, it is most economical to replace the resistors in the power supply filter with chokes. But the last cap in the power supply is effectively in series with the output cap, so it should be at least as big and preferably bigger, as well as being of similar quality.

 

[Raksasa]

Thanks for the response, Paul.

I started a thread re this, as per Grainger's request, here in technical topics:  http://www.bottlehead.com/smf/index.php/topic,2614.msg21206.html#msg21206

John

 

[pkb]

After reading this thread, I decided to try something along the lines of bypassing the output caps with some smaller .047uf caps I had lying around. I had the Sprague Orange Drop polypropylene film and foil caps sitting around from when I was working on guitar amps.

With aligator clip leads, I clipped them in and out, and in, and out, and in, and out, etc., and THINK I may have been noticing a difference. When I tried to pinpoint that difference, it went away. When I let my imagination go, I'd imagine I was hearing more space and clarity in the higher registers.

I know this is relatively ghetto compared to all the fancy caps y'all are talking about, and what I'm doing may or may not improve or even change the sound, but my question is this: how etheric and/or poetic are these differences y'all are hearing? If you're not A/B'ing the caps with the same audio (even same passage), same source, same volume, same phones, same ambient room, etc., how on earth do you know what you're hearing?

I want to get on this bandwagon, but I want to do so with a minimum of pretending to hear stuff.

I'm sure this post merits at least 10 flames, but I am being honest. It's not the Emperor's New Cloths situation I'm wary of, but rather I'm expressing a genuine interest in learning what to listen for and how.

My background: I've been a working musician, spent lots of time in recording studios on both sides of the glass, had too much musical education, and am generally good at hearing stuff.

This is all very fun. I'm going to solder in those Orange Drops and keep pretending--and enjoy my first "mod".  

-Patrick

 

[earwaxxer]

After reading this thread, I decided to try something along the lines of bypassing the output caps with some smaller .047uf caps I had lying around. I had the Sprague Orange Drop polypropylene film and foil caps sitting around from when I was working on guitar amps.

With aligator clip leads, I clipped them in and out, and in, and out, and in, and out, etc., and THINK I may have been noticing a difference. When I tried to pinpoint that difference, it went away. When I let my imagination go, I'd imagine I was hearing more space and clarity in the higher registers.

I know this is relatively ghetto compared to all the fancy caps y'all are talking about, and what I'm doing may or may not improve or even change the sound, but my question is this: how etheric and/or poetic are these differences y'all are hearing? If you're not A/B'ing the caps with the same audio (even same passage), same source, same volume, same phones, same ambient room, etc., how on earth do you know what you're hearing?

I want to get on this bandwagon, but I want to do so with a minimum of pretending to hear stuff.

I'm sure this post merits at least 10 flames, but I am being honest. It's not the Emperor's New Cloths situation I'm wary of, but rather I'm expressing a genuine interest in learning what to listen for and how.

My background: I've been a working musician, spent lots of time in recording studios on both sides of the glass, had too much musical education, and am generally good at hearing stuff.

This is all very fun. I'm going to solder in those Orange Drops and keep pretending--and enjoy my first "mod".  

-Patrick

Hi Patrick - I cant agree with you more! A healthy dose of skepticism is the best way to approach this hobby. I have not spent a ton of money on equipment. Not that I dont have it, its the principle behind it. I want to have a personal relationship with my gear as do most if not all Bottlehead fans.

With that said, I do subscribe to the audiophile axiom (not mine by the way) -  "everything makes a difference". Tweaks and kit that are priced in the stratosphere deserve much more skepticism than those of moderate, affordable price.  I have read numerous "reviews" of ridiculously high priced v-caps for example. Many of them gushingly positive. I still will never buy one because I dont believe they could possibly be a smart "value" compared to alternatives. That doesnt mean that it is "unwise" to spend significant coin on caps.

 

[Paul Joppa]

I have found that often, when a difference is subtle, I have to distract my attention so the old subconscious reptile brain can have a listen. I've even left the room and started a conversation in an adjacent room, only to realize five minutes later that - you know, that last change is really working for me.

 

[[email protected]]

Patrick, you are right on with everything except for expecting flames.  The experience of listening to music is a different experience for everyone.  It's a brain/ear thing and everyone has a different combination of those things.  What one person perceives as "bright and/or tinny" may be what another hears as "nicely extended high end".  You can only hear for yourself.

If anything, what seems to be valued most around here is an individual's right to experiment and decide for themselves what sounds good.  Those ideas are shared and we can take them or leave them depending on our own tastes and budget. 

I'm an extreme skeptic myself, but lately, I'm learning that a few things may need a second look. 

Just keep listening and let your ears be your guide.

 

[Noskipallwd]

After reading this thread, I decided to try something along the lines of bypassing the output caps with some smaller .047uf caps I had lying around. I had the Sprague Orange Drop polypropylene film and foil caps sitting around from when I was working on guitar amps.

With aligator clip leads, I clipped them in and out, and in, and out, and in, and out, etc., and THINK I may have been noticing a difference. When I tried to pinpoint that difference, it went away. When I let my imagination go, I'd imagine I was hearing more space and clarity in the higher registers.

Patrick, well spoken. I have personally found that most mods, tweaks and uprades to be highly subjective. Tubes and caps are at the top of the list IMHO. You will find that many of the folks here use A/B methods when performing mods. I had 3 types of 100uf film caps on hand when I built the crack, Solen fast caps, mundorf mkps and mundorf mtube caps. I A/B tested these using vinyl, cds, and digital files, I ended up using the mundorf mtube caps, which are suppose to be ps caps not output couplers, but they sounded best to me. If someone is happy with a stock amp, more power to them, I am envious. Honestly, if I could afford a Clear audio Statement turntable, (150,000 dollars, amazing engineering), I would probably have it for about a month before I would start thinking about how I could make it sound better. I may not be OCD, but I do have the O part.

Cheers,
Shawn

 

[Grainger49]

My favorite simile is that it is like spices.  Some people like jalapeno peppers others like Ancho peppers.  What is fit for one person isn't right for another.  If we were all the same there would be one car in the world.

I'll add wiring to Shawn's list.  Everybody hears things differently.  Not to mention a ______ (fill in an audio component or tweak or electronic component here) that sounds good in one system might sound horrible or make no change at all in another.

But do read my signature.

 

[BNAL]

I'm looking to.replace the electrolytic output caps  with film and wa.Ted to k.ow what users of the Obbligato 100uF PS have thought about the sound when used in the crack. I have used the film in oils and have been happy with the results.

 

[earwaxxer]

I'm looking to.replace the electrolytic output caps  with film and wa.Ted to k.ow what users of the Obbligato 100uF PS have thought about the sound when used in the crack. I have used the film in oils and have been happy with the results.

IMO Obbligatos film caps would be a great option to replace electrolytics. I tried them as crossover caps and really couldnt like them, but I was comparing them with top end film caps. I dont see how you could loose replacing electrolyics with them. You got me thinking!

 

[Noskipallwd]

I used 3 47uf obbligato PS caps in my Bijou, they sounded great. Can't tell you how they would perform as output caps in the Crack, but I am using Mundorf MTube PS caps as the output in my Crack and I am very happy with them. Might as well give the Obbligatos a try. I think the Premium golds are easily one of the best bang for buck caps around. The only problem I have with Obbligatos is for some strange reason,(probably my strange mind), whenever I type, read or speak the name I get that damned song by Styx stuck in my head. (Mr. Roboto). Maybe Dr. Toobz could give me some insight into that one.

Cheers,
Shawn

 

[patm]

I have a pair of 100uf Obbiigato caps sitting next to my Crack kit on my work bench waiting for me to start the build. Would also like to here if anyone else has used them.

Pat McSween

 

[jrebman]

Aside from the all the great points mentioned so far, I'd like to add that for me, even after the immediate A/B go/no-go testing, there is the much longer term test of just listening to a wide variety of cuts from your collection and just taking notice if you feel there is something you miss or really like about the change you made.  It's not even an analytical thing, just take notice of how much music you're playing and if you look forward to it, don't feel fatigued afterwards, are listtening longer or shorter, etc.  Of course this can only be done when all is well burned in, and really has to be a long term thing so as to account for normal variations in season, mood, and other things going on in life.  It's why I generally tell people up front that this is not a hobby/pursuit for the impatient .

Of course a lot of people will just want to go with whichever they find to be the better choice at the time of the modification, which is also very valid, especially after a certain amoutt of experience to guide that initial decision.

-- Jim

 

[earwaxxer]

Jim - point well taken - What you expressed so well is probably one of the most frustrating aspects of this pursuit, and clearly the most humbling.  I think that experience is why those with means drop such huge coin on kit (I'm talking about the $10k+ per component crowd). For them, time is precious and they just want to listen (taking bragging rights out of the equation). As a budget limited audiophile enthusiast, its good to know I'm in good company though!