Foreplay III stock - coupling caps suggestions sought

[syncro]

After finding out how much sound changed when rolling coupling caps in my ST-70 I have an itch to try it in the Foreplay III stock build.   I see on this board recommendation for Obligato brand, and I like the price point. 

Would Obbligato 2.2uf/250vdc Tinfoil/film Coupling Cap at:  http://www.diyhifisupply.com/node/483?t=1302234476 be the ticket?

 I thought there was a posting about Foreplay III coupling capacitors, but I can't find it now.   Somewhere P. Joppa stated, regarding coupling caps, to upgrade this first> (250v or greater voltage rating, but anything from 1uF to 10uF will work fine). 

Stock came with 2.2 uF.  What sonic effect might different values have?

 Thanks in advance.  David

[Grainger49]

You said the magic word (Obbligato) and I posted.

Yes those would be the proper voltage rating and the value is good as well.

I am a big fan of the cheapest of the Obbligato caps (630V works for everything Bottlehead).  They are slightly warm sounding.  I have suggested them for several folks with SEX amps and they have always been happy with the results.

Since they are so cheap why not get a pair of the big black ones at the same time?  And don't forget to buy the shipping from DIY Hi-Fi Supply.

Changing the value to a higher value will not change a thing as it is already flat at about 10 Hz.  Changing the value to a smaller value will change the spot where the preamp is flat on the low end.  But, seriously, who can hear a 30 Hz note (if it were in our music) in a typical listening room?

[syncro]

Thanks for the tips and info.   Now, about the

....the big black ones....

   Do you mean the Obbligato Film Oil 2.0uF 630V that start at 2.0 uF value?   I guess I could hang a couple of those under the chassis!

Looks like in the link I posted I picked out their MOST expensive - more than their Premium.   Since "coupling" is in their title, along with Tin, I figured it would be a safe bet.  The Copper is the least expensive 630v.  The Film Oil is by far the least expensive of all, the largest dimensionally, and somehow the most interesting - especially given your endorsement to try it.   Looking forward to studying the burn in method you have posted and giving it a try.

And I won't spend too much time listening for 10 - 30 Hz, until I get a test record to play it for me on cue - and a subwoofer since Fortes roll off at about 32 Hz.   ;-)

[Grainger49]

David,

Yes, the cheapest of the Obbligato PP Film in Oil are the ones that I have bought about a dozen of.  I have sent some to buddies so I don't have the dozen in my system.

I first used them on the suggestion of another Bottlehead, wish I could remember to give him credit, for the 10uF 630V Parafeed cap in my Paramours.  It was hard to find an affordable cap that size and voltage rating.

I was blown away with their sound for the very low price.

[syncro]

Thanks again, Grainger.  I'm going to try these inexpensive oil cans, burning in with your "patented" method first.  Hope to report back in a few months after they arrive and I've had a listen!

[syncro]

I burned in according to Granger's method for four (4) days and had some listening tests.  First evening we liked the original caps best.  After a couple of days use in the Foreplay III things were different.  The kids and I voted "most natural" on the new film-oil caps. 

I'm guessing that the high DC voltage I am measuring (70 vdc or so) on one side of the caps in the Foreplay III is burning them in more/differently?

Anyway, thanks for the inexpensive upgrade/tweak. 

[Grainger49]

Sadly not everybody likes the same cap, buys the same car, likes the same interconnects or speaker wire.  That makes it hard to guarantee that a suggestion will fit another person's taste.  A number of Bottleheads, myself included, have liked the cheapest Obbligato caps.  Only a few were not happy (I can't guarantee that they burned them in long enough either).

But the diversity of the human race is what keeps it interesting.

[Paully]

I have liked Obligatto myself.  But if those aren't quite what you like or you just want to try something else, Auricap is always a perennial favorite and that is what I have in my FP III.

[syncro]

Still listening to these big Obbligato film oil caps and digging the sound.  Briefly re-tried the stock caps and I would still say the difference is subtle, but the Obbligatos are winners and will be soldered in place soon.  Maybe single-ended tube amps, e.g. Paramours, would make the difference more clear, but the Dynaco ST-70 is still in-line to my Klipsch Forte IIs. 

Thanks, Paully for the reassurance that Auricaps can be another viable option someday.  May try upgrading my speakers' caps next, but that will be another thread.

[dbishopbliss]

I have a pair of the tin caps that you mentioned in your first post.  I haven't used them in my Foreplay, but I was swapping them in during the recent Bottleneck Linestage Competition.  My entry was very similar to a Foreplay I.  The difference was not subtle at all compared to the russian PIO caps I was using.  Very smooth and natural. 

[syncro]

Thanks for the opinion/description on the tin caps I first posted about.  I did not end up getting those.  Maybe they would be more noticeably different/better at $40 /pair than the very inexpensive film-oil caps I purchased....  Good to have another option to try someday.

[Mr. Lin]

On this topic, I've just received in the mail a pair of 2.2uf Jantzen Superior "Z" caps (the red ones with copper leads), which are presently sitting on a bread board and being burned in with a Hagtech Frybaby (along with a .1 uf Jupiter cap I'll be trying for the OD3 tube).  In another three or four days I'll probably take them off the Frybaby and put them in my FP III, so I'll let you guys know how that works out.

[Thoburn]

On this topic, I've just received in the mail a pair of 2.2uf Jantzen Superior "Z" caps (the red ones with copper leads), which are presently sitting on a bread board and being burned in with a Hagtech Frybaby (along with a .1 uf Jupiter cap I'll be trying for the OD3 tube).  In another three or four days I'll probably take them off the Frybaby and put them in my FP III, so I'll let you guys know how that works out.

I put Jupiter HT caps in my Stereomour and am very happy with them. They are rather expensive. If you just change in the Jupiters by themselves first I would be very interested in your evaluation.

[Mr. Lin]

I put Jupiter HT caps in my Stereomour and am very happy with them. They are rather expensive. If you just change in the Jupiters by themselves first I would be very interested in your evaluation.

While I wish I was referring to the HT Jupiters in my last post, unfortunately it's simply a Jupiter "Vintage Tone" film cap that I put across the OD3 tube, tonight as a matter of fact.  It's hard to say for sure, but listening to piano music by Schubert that I've been playing nightly for the last week, there almost seems to be more background detail, like a creaking bench and pedals, etc.  Perhaps it's a lower noise floor?  I don't know.  

I'm building Paramours right now, and I intend to eventually put Jupiter HT caps in them, since I find the beeswax idea very intriguing.  I know it's a little ridiculous to start picking exact upgrade parts before you're even finished with the thing, but if ever there were a sympathetic crowd, I suspect I'm probably among them here.

So Thoburn - what improvements did you get from installing the HT caps in your Stereomour?  

[Doc B.]

Yes. a bypass cap across the gas reg will give you a more quiet background. Bear in mind that a "vintage tone" (smells like old wax?) probably means that the cap's sonic character is a bit mellow. That might be the thing you want for a coupling cap if you need to tame the top. But for a bypass cap where you are trying to shunt off some noise you might want to consider a "modern tone" ( smells like polypropylene?) cap that is intended to work well at very high frequencies.

Speaking of Jupiters, does anyone know of any research done about their stability with time? The reason I ask is that I have begun to restore an old Hammond organ (ca.1942). One of the biggest issues with Hammonds of that era is that about 40 or 50 caps in the tone generator are wax caps used in tuned filter circuits to eliminate higher harmonics from the tones, and typically those caps have increased in value about 80% over the years, lowering the filter frequency and making the highs very dull compared to the mid and bass notes. Hammond switched to mylar caps in 1954, thus solving this problem, and the usual restoration procedure is to recap the whole thing with mylar caps, which creates controversy over the change in sound. Might be interesting for Jupiter to make wax caps just for this app if they remain stable with time.