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Old 7th December 2012, 11:07 PM   #31
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i've been looking for affordable film caps for my 930v gm70 amp, farnell have some 40uf/1100v polypropylene by i think panasonic ? at 11-12+vat/p&p but they are showing as not in stock yet. they are only a couple of inches in there longest dimentions so even my chassis could fit 4 or 5 paralleled.
enzo
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Old 8th December 2012, 12:07 AM   #32
kevinkr is offline kevinkr  United States
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Funny I have a fair number of both graphite and copper plate GM70 and can compare them on whim. And have spent a lot of time with both..

They don't glow, (@120W of dissipation >1K hours so far) although the reflections off the copper on the inside gives them a very odd hue.

They also don't sound tremendously different from the graphite, maybe just the subtle difference between the taste of a typical bag-in-the-box red and a bottle of Mouton Cadet. (They are both red wines after all)

I will say that at 3X the price of the graphite plate version they are a serious bargain.
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Old 8th December 2012, 12:35 AM   #33
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Originally Posted by gaborbela View Post
Hello
These capacitors are good for these amplifier or better to use oil caps. I see most builder use oil caps (just because cheaper or they perform better ??)
SCR 51F 1500V-DC Polypropylene MKP Audio Capacitor for 211 845 GM70 813 2A3 | eBay
Also I purchased 12PC Epcos 1000uF 300VAC MKP capacitors (at Digi-key 1PC/$100) On 12PC they gave some discount..
I will post picture soon, I don't know if it worth to give a chance for those or I just sell them.
Greetings Gabor
Any opinion on these caps?
Please.
Greetings Gabor
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Old 8th December 2012, 12:45 AM   #34
kevinkr is offline kevinkr  United States
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I've used the 51uF/1500V solen in a number of designs, no problems to date..

I'd probably get them direct from Solen here: https://www.solen.ca/pub/index.php?c...1%3D2%26s2%3D3

Would you have to pay customs duty on the eBay caps as they come from France?
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Old 8th December 2012, 01:22 AM   #35
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Originally Posted by kevinkr View Post
I've used the 51uF/1500V solen in a number of designs, no problems to date..

Would you have to pay customs duty on the eBay caps as they come from France?
Hello

Not always sometimes they just forget or I don't know these works.
Last time I ordered a pair 10" Alcone woofer from Germany cost over $300 plus shipping and no custom duty nothing.
One day someone donated 10 caps here at the forum for free just I was asked to pay for the shipping cost
So he sent it as a gift.
They open up the package at the border and estimated amp charge me very high custom duty...
Hard to understand what is going on.
I just wanted to know why DIY-ers preferred oil caps, to me these look like great capacitor for these project.. Nothing to do with that business!

Greetings Gabor
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Old 8th December 2012, 01:43 AM   #36
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Hello
The main reason I asked because I have 12PC of these Epcos capacitors
B32361A2157J050 EPCOS | Mouser
I know they are horrible expensive (I got it cheap com pare to the orig price and brand new in their orig boxes)
I will build 2 mono block, I want to use at each mono block 2x3PC and between a 6H choke.
Who knows may be it would be better to sell them and buy something like Sollen.
I think if Sollen good these one is good to, or you didn't use that in the PS but they are very expensive!!
I didn't knew Sollen has such a high voltage caps. Good to know in case..
Thank you
Greetings Gabor
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Old 8th December 2012, 12:54 PM   #37
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Originally Posted by kevinkr View Post
Funny I have a fair number of both graphite and copper plate GM70 and can compare them on whim. And have spent a lot of time with both..

They don't glow, (@120W of dissipation >1K hours so far) although the reflections off the copper on the inside gives them a very odd hue.

They also don't sound tremendously different from the graphite, maybe just the subtle difference between the taste of a typical bag-in-the-box red and a bottle of Mouton Cadet. (They are both red wines after all)

I will say that at 3X the price of the graphite plate version they are a serious bargain.
So in other words the coppers are waaaaay better.. lol
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Old 8th December 2012, 04:58 PM   #38
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So in other words the coppers are waaaaay better.. lol
Hello
That not that simple choice like black or white
There are people who prefer the graphite over the copper..
All depend how the amp built, sweep spot set up etc. etc
I'll build my amp with graphite and will test the copper later, copper can sound thin to those who prefer graphite, or the amp was set up to graphite
There are other reason to why people chose copper..
So many times I read the shipping can be problem, if not well packed or stored graphite can has very very thin cracks which lead to distortion or worst later
You can imagine that tube warms up and cool done so many times.

Greetings Gabor
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Old 8th December 2012, 05:17 PM   #39
djn is offline djn  United States
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Good luck on your build Gabor. I have a half done GM70 sitting on my bench. We are finally settled in our new house so I am back to messing with audio. If you've not looked into it, you should check out Rod Coleman's DHT filament heater boards. You can get away with using a hum pot on a 2A3 or 300B but with 20v on the heater of the GM70, a hum pot won't keep out the noise regardless if you use a copper or ceramic tube.
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Old 9th December 2012, 01:09 AM   #40
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by gaborbela View Post
Hello
That not that simple choice like black or white
There are people who prefer the graphite over the copper..
All depend how the amp built, sweep spot set up etc. etc
I'll build my amp with graphite and will test the copper later, copper can sound thin to those who prefer graphite, or the amp was set up to graphite
There are other reason to why people chose copper..
So many times I read the shipping can be problem, if not well packed or stored graphite can has very very thin cracks which lead to distortion or worst later
You can imagine that tube warms up and cool done so many times.

Greetings Gabor
I've yet to meet anyone in person who has used both who prefers the graphite over copper. I find them to have all the same strengths as the graphite, but with significant improvement in finesse, better micro-dynamics, and an overall cleaner sound in the mids and highs. No deficits either. I have more than a half dozen of each and ran graphite for about six months and switched to copper almost a year ago.. I have heard the same from a number of people running GM70s of quite disparate design. (IT coupled as mine are, to choke and RC coupled - most running at 900 - 1.2kV.)

Compared to the more exotic versions of the 300B, any 50/250, NOS single plate 2A3 and others the GM70 in any incarnation is pretty cheap.
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