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First, ALL the grungy-sounding resistors, caps, and magnetic hookup wire everywhere in the amp will be replaced with HIGH-quality stuff, so PLS let us not get drawn off topic in this thread.
The amp currently uses a quad of cheap, edgy-sounding (IMO) Solen FastCaps**, 47/630s, with no bypass caps, in the only capacitance following the choke which follows the 5U4G 'rectifier'*. See the link for the schematic diagram.
After considering many alternatives including motor-run caps, the current alternatives for that about-200uF of capacitance are as follows. Not included in the descriptions of the alternatives below are whatever small, HIGH-quality film-type bypasses I might use. Since all of these alternatives are affordable, price is not a factor.
1. Obbligatto film-and-oils, one 70uF plus two 47s plus a 33, totaling 197uFs.
2. WIMA 600VDC DC Link, rectangular, one-each 100uF, 60uF, and 40uF.
3. WIMA 700VDC DC link, cylindrical, one each 143uF and 59uF.
If you've had experience with any of these in poweramp PSs, I'd love to read about it.
* That's in quotes because it's doing no rectification, being fed with filtered DC.
** and if you like the sounds of these caps, I'll soon have 8 for sale, cheap! :-)
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Follow Ups:
I use Wima DC link (big red rectangular ones) in tube power supplies and I like them a lot. I tried Solens here and there, and I always removed them as they give metallic tinge to the sound in the upper register, like a cheap class D.
...the WIMAs with smaller cap(s)?
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 05/02/14
Jeff,
It's been quite some time since your last post( busy with your project). How did the modifications of your Frankenstein turn out? How does the sound quality differ from the stock Frankenstein? Was the final result what you had expected?
Thanks,
Charles,
...the output-stage PSs with the 3 (bypass) caps I chose, those being...
1. Jupiter HT 2.2/600, Mundorf SO 1.8/1200, and Reliable RT ('styrene) 0.47/600.
I installed, temporarily, a trio in each amp and have been listening to the system...GASP!!!!!!!!...for months. Got busy with my other obsess...er...hobby, fotografy.
Don't know when I'll get back to the Frankensteins.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
sorry if I spoil your excitement but I doubt that you will get any signficant better sound by changing this cap to that cap. The Solens are okay! better caps give you a tiny bit of improvement if you know what you are doing and you have experienced ears.
As a first time moddler I think you should not be very excited. Most of the time you will upset the balance of the parts and the overall sound of the amp, and it is very easy for newbie to do a bad solder joints (or a few) and position the caps in most funny ways (read: very electrocically bad layout). To put a product like this in the market, there is a lot of experience and technical know-hows on the part of the manufacturer and many years of circuit & parts swapping.
Changing a few caps may add or subtract very small flavour. Its not worth the effort. Having gone through practically all audiophile capacitors, I indeed now believe all the reported "jaws dropping" differences are imaginary in the minds of most of us. But do not rule out the possibility that I have shitty ears.
then wait for the caps to break in and the frustration that comes with that
then you read about low dcr power supplies, constant current fillament supplies and all the other interesting topics over in the diy forum.... you thought you could try a thing or two. by then you will realise you are truly hooked for enternity. good luck my friend, you will never be able to enjoy your music like you should.
if I were you, I would just cancel the cap orders, buy & listen to more music and try to do other things like learning how to cook...
...a 'first time (sic) moddler (sic)'? In fact I've been doing this stuff for about 35 years--remember Peter Moncrieff's Wonder Caps? Yes I know that parts upgrades make only small improvements and that sometimes they may not be worth the money. BUT...I'm not spending the mortgage or food money and can afford it.
IMO the cumulative results of these kinds of improvements...these small changes that may not be quickly audible by themselves...are what have improved the sounds of my systems substantially over the years.
Vincin, YOU learn how to cook; cooking bores me. Large-scale Classical music, live and reproduced, enthralls and thrills and rewards me, and I'll continue to improve my system as I wish.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
First I'll remove the original caps and their mounting bracket and splice a few wires that run thru it so that I can reinstall the original if I wish.
After replacing the original cap bracket's chassis-ceiling-reinforcement function with maybe a couple aluminum angles, all subsequent sets of main caps will be mounted on some sort of platform that can be removed and replaced fairly easily. Fortunately, there's lots of room in the amps.
After considering many 600VDC-and-above main and bypass caps, the first set back in will likely be a combination of 630VDC Obligatto* film-and-oils in 70- and 47uF with a 39/630 Clarity ESA* for 156uF. I'm still considering the 143uF WIMA DC Link 700VDC cylindrical...
http://www.mouser.com/ds/2/440/WIMA_DC_Link_MKP_5-1184.pdf
...as the base cap, to be combined/'flavored' with probably the Obligatto film/oil. At $44 per 143uF for a 700VDC metallized-'propylene cap, this WIMA is the bargain of any I'm looking at.
Bypasses will be some combination--and probably all of--a 0.47/600 Reliable RT ('styrene'), a 2.2/600 Jupiter HT (beeswax/paper/aluminum foil), and a 1.8/1200 Mundorf SO, all 5-star caps in my world. Probably I'll mount the bypasses NOT on the main-cap platform but directly on the ceiling of the amp.
Pics later.
* currently on sale at Parts Connexion and Madisound, respectively
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Hello Jeff,
Despite your disappointment with some parts quality at least you and a trusted friend find the sound to be very good. That was my only point, it sounds better than many others I have heard. If you can improve the Frankenstein further, all the better for sure. I will follow your progress with interest, good luck.
Charles,
not for the PS caps but if you still need small film caps. Newly launched Jupiter copper foil paper & wax caps are now available from Sonic Craft and Parts Connexion. I am listening to them right now, and they are extremely good sounding film caps, detailed and clear yet rich and musical. It has top-class performance at middle-class price :)
Jon,
How to they compare with other PIO's you have used? I'm considering using them or Vitamin Q's on my input tubes.
Les
Jupiter copper is not paper in oil but paper & wax, and it is much more detailed and clear than PIO's like Vit Q, Jensen copper PIO, Russian K40Y, etc. PIO's do have their unique charm and forgiving warmth but not the resolution of Jupiter copper. What is sweet is Jupiter copper is not all detail but adds its own brand of colorful, organic richness. I like Vit Q, but I would take the Jupiter copper over it all day long..
Hi Jon,
Off-topic warning.
Thanks for sharing your experiences (in the now and past). I have been working with Chris to get a set of Cu foil caps for speaker crossovers. He has been helpful... just waiting to see what can be done re: a 22uF for the tweeter circuit.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
ElCon has MANY metallized 'propylene hi-Voltage caps available. After some research, I'm considering the UP2 and UP37 series of 600VDC caps. See
http://www.ecicaps.com/pdf/capacitors/UP2_full.pdf
and
http://www.ecicaps.com/pdf/capacitors/UP37_full.pdf
The UP22s--radial leads--are available in 40-, 55-, and 65uF, while the UP37 is 30uF only but it's rather small. I've e-mailed their sales company, asking if they're at all magnetic, what material they use for end-spray, and prices. We'll see.
FWIW, there's plenty of space inside the amps for any of these PS caps and bypasses. I'm likely to start with some amount of capacitance around 150uF, and it'll be easy to add more.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
I'm seeing a sand bridge rectifier and a 5u4 followed by a choke that is only good for 100 mA. With the bleed on the end, that choke has to be pushing 90% current capacity for 10H.
Before I mortgage my house on boutique Caps, I would consider working the impedance down on your PS if the down stream can handle it(IMO). I'm with Mike on the Black Solens in the PS...you will be hard pressed to get RIO by changing them out.
I saw the pictures early...looks like a nice build...
Stuben
...are highly affordable--the most-expensive alternative (Obligattos) is only $265 for both amps including relatively expensive bypass caps.On the lower-R choke, I'm considering it.
On the Solen Fastcaps, what they're really good for is providing a relatively high amount of capacitance in relatively low space and at a relatively low price. They do that by (I believe) using thinner film than other manufacturers' same-Voltage-rated caps. Also, the zinc they use as end-spray is about the worst-sounding metallic material imaginable. The result is a relatively small and inexpensive cap that sounds edgy to LOTS of us out here. I may not be a GEA, but I'm sensitive to that sonic sin, and I can hear it from the Solen FastCaps. I can afford better, so why not?
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 04/23/14
$265.00 for those puppies is pretty good. I have used the black Solens for PS smoothing...I can't say that I have ever regretted it....as a Parafeed or coupling cap, no way.... done that. No comparison to good PIO. I have used the military Russian Teflons for coupling....takes some break in but wow...
Have fun...
Stuben
In-between the sand FWBR and 5U4 is (C1) a voltage doubler 220uf 450V.
I've used the Obbligatos in several projects, most notably the Parafeed Caps in my 45 amp. and like'm. Very neutral.
If you have the room, tho', try Vintage Aerovox, oval cans only, for power supply.
Jeff,
Why don't you over-spec the voltage and simply use the Wima 800 VDC DC Link caps?? Less chance of a failure when you are gone and the grandkids are using the amp.
Jeff Medwin
.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Jeff
The best bypass caps in a power supply are paper in oil.I understand about the black Solens being very sharp in the signal path but the film and foil caps they make are fabulous.They are a true film and tin foil and are not metallized..The higher value 47uf solen black caps used in the power supply seem to work well..I don't think you will get a major change going from one metallized poly to another but the Wimas and Panasonics are cheap enough to try.
I do think you will get a very desirable change putting 1uf to 2uf MBGO
pio caps across the 47uf Solens. You can put your own leads on them and if you have the room,it will be the option that gives you the most improvement.
Honest amplification is better than excessive 2nd order distortion anytime.
Edits: 04/21/14
Not so much energy in the power supply is there? Or does the choke eliminate the need for a larger cap bank? I only note this because I had a pair of Cary CAD-572se monos that had about 1200 uF each and I have a JJ 322 parallell 300b with 1500 uF per channel. Neither of these designs used a choke in the power supply.
I share your opinion about the Solens, but don't get too hung up about duplicating the 200uf value. I suspect anything in the 100uf on up range will work just fine.
Also, I nearly always prefer the sound of a single cap of the proper value than several caps in parallel. But if you really need multiple caps to get the value you want, use two or more of the same cap---same type and same value.
I think that it is shameful that a $5K+ amp in current production should needs this.
They don't need any of this. It is a very very good amp as is. If the OP wants to make these changes it's up to him. He could very well ruin the amps as much as improve them by blindly making changes. Whatever the end result I hope he's happy with them, but since none of us will hear them it's his subjective opinion.
I know of many owners perfectly happy with them as is.
Dan Santoni
Edits: 04/24/14
Blackdog,
I share your assessment of the Frankenstein MK II but I realize and respect that we all hear differently and have individual goals. I hope Jeff reaches his with this ongoing project. I wish him the vrry best of luck.
Charles,
...amps are very happy with the sounds they're getting.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 09/21/14
Hi Jeff,
With the shortcomings you seem to be discovering what other commercial 300b SET would you prefer in hindsight?
Have you considered just building your own DIY custom amplifier?
Yep, I am a very happy owner and surmise we just hear differently as this amp has bettered many other amplifiers I've heard(although there's room for improvement with nearly any product I imagine).
It seems the Frankenstein would be a good match with your new speakers, are they?
Thanks,
...that the Frank.II was about as good as money could buy, and that's why I bought them. BUT, same as in about all other areas, you don't discover the shortcomings until you've paid your money and received the product. Blume bragged about all-polypropylene-cap main PS...and I got cheap, edgy-sounding Solen FastCaps. He bragged about NO coupling caps in the signal path...and I got a not-quite-as-cheap Solen 'propylene-film-and-foil coupling cap. He bragged about highest-quality Teflon caps in the amp...and there are none to be found. I believe the design is very good, but the quality of almost-all parts is not-at-all excellent and in fact (IMO, at least) rather poor. For instance, what high-end-amp designer would use resistors and capacitors with magnetic leads? Who would use magnetic hookup wire????????????????Oh well...all that stuff will be gone in a couple months.
And RC Daniel is correct--I have NO interest nor adequate knowledge to build amps myself. If I built a pair, probably one wouldn't work at all and the other would hum so badly it'd be unusable, and then it'd cost me a kilobuck to get them running.
I initially missed your question about matching the speakers--yes indeed they seem to drive the MR and tweeters of the Serenity Super-7s very well. I've not changed the coupling-cap value nor added a front-end high-pass filter, so the amps are driving full-range signal into the MR/tweeter section. My intention is to use a 0.01uF coupling cap which, with its 330K load resistor, will create a 48Hz high-pass filter, which will reduce--I almost typed 'block', which of course filter caps don't do--much bass energy from the midrange drivers, and I imagine they'll sound better for it.
A VERY-golden-eared goodbuddy heard my system the other nite and uttered 'That's the best I've ever heard this' while listening. He also said that my system was now about the best he has ever heard, all of which made me feel really good...and it'll be sounding even better in a couple months. :-)
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 04/25/14 09/21/14
As you know and relatively speaking, there is a lot involved in building a decent amp.
Jeff probably has considered it... but the constraints imposed by an existing design make modding, er, voicing, an amp much is easier. The Franken-whatever is probably as suitable place as any to start.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
If room permits, three 47uf 370v motor runs paralleled and no bypass caps.
A fourth if needed but I doubt so.
F&T makes very good MPP caps in 47uf. Rebranded for Mundorf.
Then decide what you wish to do with the FE rectification.
Cheers,
W
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