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Modern Caps,Vintage gear

64.216.25.89
Posted on March 24, 2001 at 20:58:34
Pland


 
Hi,
I had always been discouraged from using "designer "caps in my 299a/b Scotts."Too dry","Disturbs the original sound",etc.
I had some Auricaps in the right values for my 299a and decided to try them,as this amp needed a rectifier and coupling caps.Plugged it in,and was initially unimpressed,but it was definately less rolled off and sounded a little more like a 299b(crisper highs,punchier).I accumulated about 10 hrs. on it,and lent it to a musician friend who wanted to listen to a tube amp.
I used one of my 299b's(Xichon caps),but I kept missing the 299a,which was odd,as I've always preferred the "B" series.About a month later,I got the 299a back(my friend had a death grip on it),and was shocked to find that it sounded even better with some break in with the caps.It totally outclassed the "B";airy highs,super defined mids,much faster bass.
Needless,I tried the same caps in a 299B.Same thing.Initially sounded too shrill,forward.After about 30 hrs,suddenly the sound bloomed .Both of these amps now sound as fast and articulate as modern equipment,but with the "voicing"of the great vintage sound.
In summary,I'm now a believer in two things:
1.Modern analytical capacitors enhance,rather than disturb vintage equipment.
2.Passive components really do require a break in period(I had always believed this to be either B.S.,or psychoacoustic).
Best,
Pat

 

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Disclaimer, posted on March 24, 2001 at 21:06:03
Pland


 
BTW,
I don't represent or advocate any brands of capacitors.In fact,I can't tell the difference between Auricaps and Hovelands in my two Foreplay preamps.Both ,however,improved the performance dramatically.
Best,
Pat

 

Re: Modern Caps,Vintage gear, posted on March 26, 2001 at 01:47:22
scrooie looie


 
Try Sprauge "6PSP" orange drops.Let`em burn in.For a lot of vintage gear,they work out.Good Luck scrooie looie

 

Re: Modern Caps,Vintage gear, posted on March 26, 2001 at 19:40:48
tc


 
Would you recommened the same Sprauge "6PSP" orange drops for some vintage Fisher gears (receivers and amps)? What should I expect from them in comparison to others? Many thanks in advance.
tc

 

Re: Modern Caps,Vintage gear, posted on March 27, 2001 at 06:47:08
scrooie looie


 
Hi tc,
Yes,I`d recommend the 6PSP for Fisher.I have a good number of Fisher poweramps as does a good friend of mine,so I always have the opportunity to compare the differences between caps.BTW,I try to collect units with close serial number groupings when making listening judgements in regard to a type of cap that works the best for me,sonically.Currently,I`m comparing Model 200 monoblocks.One pair is using Illinois caps,the other is using 6PSP.We`ll see what happens after a few months of burn in.I`ll say less about Fisher recievers,only because I`ve never been crazy about 7591 based amps in general.6PSP seem to work out well in the earlier EL84 type integrateds though.
I like 6PSP because they`re fast,but not lean.Most of all they don`t tend to smear the focus in the mid bass/lower midrange the way many film types seem to do.This other group of caps includes the Sprauge 715P series.Many film caps give vintage gear a somewhat vauge midband with tinkly highs,but not the 6PSP in my experience. But,most people either don`t practice,or believe in,patiently burning in parts after a rebuild.Ya gotta give it time.If you rebuild,plug the unit in with a load,and let it burn for about 50 hours on and off before you listen for the first time.I do this so that I don`t unduly prejudice myself against a change.After about 200 hours,the parts start to settle into a place they will stay,sonically.Then one can make judjments about the personal sonic value of that part in that application.Good Luck scrooie looie

 

Re: Modern Caps,Vintage gear, posted on March 27, 2001 at 10:39:52
Pland


 
Hi,
Ditto on the break-in period on caps.One of my 299B's is absolutely stock and must have very low time,based on condition(original Tele 12ax7,Scott 6bl8,RCA 7189,all test very good).Great reference for comparison,it has the original Cericaps.
I haven't tried the Sprague caps,but so far,the Xichons seems closest to stock.Light on the top,solid mids,muddy bass.As Joe Rosen likes to describe Scott,zzzzzzzzzZZZZZZZZZZZzzzzzzzzzz!The Auricaps speed everything up without thinning out the mids.Much better detail,with better clarity.
I tried the Illinois caps in this amp as part of a rebuild(VTV kit),and was underwhelmed.Less articulate than stock,thin midrange.I left it that way for about 6 months,and it never really opened up.
I'm doing a light re-do on an Eico HF81 I just bought,and will try the Sprague caps.I'll keep you posted.
Best,
Pat

 

Load question, posted on March 27, 2001 at 10:49:41
Pland


 
Louie,
I set the bias on my amps using a 2w 16ohm resistor across each speaker + and -,with the taps on the 16ohm terminal,volume all the way down.Does this constitute a sufficient load to safely run an amp to break in caps?
Pat

 

Re: Modern Caps,Vintage gear, posted on March 27, 2001 at 20:59:47
tc


 
Hi Scrooie,
Your advice is very much appreciated and I will look into that. I do have some more costly Jensen oil caps of same specs (fro Fisher) but haven't managed to give them a try. I'll need to learn the basic techniques first. BTW, how come I haven't heard much talk about those modern oil caps in vintage gears, regardless the cost? Are they inferior in such applications? Just wondering...
Thanks again, tc

 

Re: Load question, posted on March 27, 2001 at 23:21:42
scrooie looie


 
Pat,
A 2w resistor is fine as long as your sure not to drive a signal into the amp,but it would`nt hurt to get 2 8ohm@20w resistors from Radio Shack,put them in series,then connect them to the output of the amp.It`s also a good idea to underfuse the unit during this static burn period,just in case an output tube goes cherry on you.Honestly, in 20 years of doing amp shootouts,I,or anyone I`ve known,have never loaded an amp for warm up,and nothing has ever gone wrong,ever.But still,I won`t recommend that to you,`cause if I do,your amp will probably go down and fire lightning bolts through your family pet!So please,load your amp like the good book says! Good Luck scrooie looie

 

Re: Modern Caps,Vintage gear, posted on March 27, 2001 at 23:49:43
scrooi looie


 
Hi tc,
While I`ve tried the majority of film caps out there,my oil cap experience has been limited to various Vitamin Qs for small signal applications in pushpull amps.They have`nt worked out for me.So,I can`t speak intelligently about other modern types.On the other hand SETs seem to react quite differently to oil caps in the signal path,but that`s a different forum.
Soon I`ll be trying some Ampohm oil caps in my vintage gear,mainly due to their higher impedance.They may behave in a way that is similar to the original types found in many vintage amps.We`ll see/listen.
Good luck scrooie looie

 

Re: Modern Caps,Vintage gear, posted on March 28, 2001 at 00:17:45
tc


 
Yes, please share your listening impression here (or in email) once that's done, I'll be interested in trying that. Where can I acquire these Ampohm oil caps?
tc

 

Re: Modern Caps,Vintage gear, posted on March 28, 2001 at 02:23:14
scrooie looie


 
Ampohm site-http://www4.topnet.it/vintagehifi/ampohm.htm

 

716P, posted on March 28, 2001 at 06:05:49
Francis S


 
i haven't tried those spragues on my amps. i'm not familiar with the sprague "6psp" and am wondering how they compare with the more common sprague "716p". any experience with the 716p?
thanks

 

Where can I get Sprague 6PSP caps?, posted on March 28, 2001 at 14:30:28
Jim V


 
I've found 715P and 716P caps, but have not seen 6PSP caps. They are not listed on the SBE website either. Thanks.

Jim

 

Re: Where can I get Sprague 6PSP caps?, posted on March 28, 2001 at 17:14:46
scrooie looie


 
Check out pg.24 of the Antique Electronic Supply catalog.They are type"PS"polyester film 600v(480)820-5411.or,www.tubesandmore.com.

 

Re: Where can I get Sprague 6PSP caps?, posted on March 28, 2001 at 19:22:32
Jim V


 
Thanks Scrooie. I looked there earlier today, but they don't have the correct values for my amp. Is there really a big difference between a .068 uF and a .1 uF cap? And are the 6PSP caps that much better than the 715P or 716P caps? I have a Sherwood S-5000 that I want to recap (at least the coupling caps), change the selenium rectifier and change the filter caps (which seem to be the hardest thing to find, although AES has some close ones). Thanks.

Jim

 

Many thanks, and please keep us informed. (nt), posted on March 28, 2001 at 20:51:23
tc


 
(nt)

 

Re: Where can I get Sprague 6PSP caps?, posted on March 30, 2001 at 16:39:47
scrooie looie


 
Hi Jim,
I called Antique and they do have them in stock,part#c-sd068-600.If you had to increase the value from .068 to.1,"typically"it does`nt matter,but,if you could find the correct value,stick with that.
I would never say that one type of cap is better than another.In my opinion the 6PSP type balances well with vintage amplifiers that are usually populated with carbon composition resistors.Leading edge transient information in the rythym ranges keep their "bite" with the 6PSPs.At the same time,high frequency info does`nt get sizzly.For me,this is a good thing.The 7 series seems to smooth over some of the bite in the rythym ranges.This may be a good thing for certain systems and certain tastes,but not for me.There may be situation where my opinion may be reversed,but so far it has`nt been.Good Luck scrooie looie

 

Re: Where can I get Sprague 6PSP caps?, posted on March 30, 2001 at 17:14:13
Jim V


 
Thanks Scrooie,

I think I've decided to replace all 23 brown drops in my Sherwood. No reason other than it seems like the thing to do. They all appear to be in great shape. Everything I've read about the brown (or some people call them chocolate) drops is bad. Since I need 7 different sizes of caps, I will probably go with the Sprague 716P since between Angela and AES I can get every size I need. I'll probably change the coupling caps first and then slowly work my way around seeing if they really make a difference.

Every resistor I've checked has tested well within tolerance, so I think I'll leave them for now. The selenium rectifier has to go, but I'm very confused as to how the substitute diodes (or maybe a FRED). Every explanation I've seen refers to 2 wires connected by the diode. My SR has two transformer leads going into the ends and a third connection coming out of the middle. From the schematic, it appears that I would connect a diode to each transformer wire and the ends of the diodes together, which end would connect where the third connection was made on the SR. I'm going to have one of my electronic expert friends look at it before I do it.

The amp sounds very good to me, except for a very low level AC hum when the volume is all the way down. I assume that's the filter caps, which are proving to be a real pain to find. I may change the large one (easiest to find a close substitute) and wait on the small cans. I can't find a 250/150@50v two section cap anywhere on the web. I've found some 500v cans that are close, but I've also read that you shouldn't jump that much in voltage with an electrolytic cap. I think I'll call AES to see what they've got that's not listed on their site.

Thanks again for your help.

Jim

 

Re: Where can I get Sprague 6PSP caps?, posted on March 31, 2001 at 10:42:50
Pland


 
Hi,
Try www.vibroworld.com for can type capacitors.They will custom manufacture caps with the values you spec.Prices aren't any higher than Aero,Mallory,and you'll get the correct uf,v.
Disclaimer:I don't know these guys or have experience with them.I got their name from a guy on the HH Scott forum,who was very satisfied.
Best,
Pat

 

Re: Where can I get Sprague 6PSP caps?, posted on March 31, 2001 at 15:08:31
Jim V


 
Thanks Pat. Sounds like a great lead. I'll check it out. Cheers.

Jim

 

Re: Modern Caps,Vintage gear, posted on April 2, 2001 at 10:52:39
tc


 
Hi scrooie,
Do you mind if I send you an email, instead of posting my naive questions here? Thanks.
tc

 

Re: Modern Caps,Vintage gear, posted on April 28, 2001 at 20:45:06
john curl


 
Pat, welcome to a new world! Newer caps have LESS linear distortion, it is also called dielectric absorption or DA. This makes signals peak and stop better (trust me), and this can be a blessing or a curse. If you want accuracy, then it's good. If you want forgiveness of whatever the source is, then it can be a problem.

 

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