[bassboy]

I know a thing or two about a thing or two but input coupling caps are not either of those 2 things.  I have a couple of gen1 sonic impact amps and am planning to upgrade Michael Mardis style (input coupling caps only - for now).  His upgrade pic clearly shows 2.2 uf Auricaps, ~$17.  I also found stuff online that should work for anywhere between $1 to over $100 each.

Not wanting to deal with shipping, I looked in my big bag of junk and found some pairs of 2.2 uf caps, but they look like this.  Mine are orange though.



After searching, it appears that these may be metalized polyester film caps, and they are usually described as being good for coupling, although they appear to be worth about 50 cents or less retail for this type of cap.

Markings:
Phillips
2.2 uf 10%
250V - MKT

Are these suitable for amplifier input coupling caps?  If not, what is the cheapest I can get away with?  Solen and partsexpress seem to have several options at around $2 - $3.  Is the Auricap worth $17 (each) considering the caps (and binding posts and case etc) will vastly overshadow the price of the amp?

Usually I do my own research into these types of things, but after spending the day researching I have found that I really have no interest in the subject of caps and would prefer if someone would just tell me how to proceed.

[bassboy]

The mods are here.  http://www.michael.mardis.com/sonic/inputmods.htm  I'm planning to do #3.

[poseidonsvoice]

I agree the Auricaps are expensive. The other contenders you should try are SonicCap Gen I's and Obbligato Copper caps. The Clarity caps are inexpensive and sound good as well.


For Clarity APW caps see here: http://www.diycable.com/main/default.php?cPath=35_139
For Sonic Cap Gen I's see here: http://www.soniccraft.com./sonicaps.htm
For Obbligato Copper see here: http://www.diyhifisupply.com/?q=catalog/22/obbligato_copper_caps

From a sonic soundpoint I would say they all sound good but you get more resolution and dimensionality with the Sonic Cap and Obbligato Copper. The Sonic Cap and Obbligato's are also more expensive. And this is only a limited list as I sense that you have a limited budget. The Clarity APW caps are good but I haven't compared them directly with the Auricaps. The Sonic Caps and Obbligato Copper better the Auricaps in nearly every way imho. They are also less expensive! You can go crazy with Mundorf Silver/Gold In Oil, VH Audio or Duelund capacitors but I don't think that's what you want here.

All three of them will absolutely trounce the polyester cap you have listed which I use only in my filament bypass supplies.

For what its worth, have fun, and good luck with your upgrade

Anand.

[bassboy]

All three of them will absolutely trounce the polyester cap you have listed which I use only in my filament bypass supplies.

Thanks so much, that's what I needed to know.  I kind of suspected that but couldn't confirm.  And it's not necessarily that I have a budget, as much as I have a hard time wrapping my head around upgrades that cost several times the retail price of the amp.  I have no problem paying a few more bucks for something better, but there's no way I'm paying $100 each or more for some of the caps I've seen.  Solen is local (canadian - this helps a lot with shipping), and they seem to have some choices in the under $5 range too so I'll compare those (as much as I can over the internet) with the suggestions you gave, and also see if I can source the Sonic Cap and Obbligato from a cdn source (solen probably has those brands too, and if not I`m sure I can find them somewhere.)

By the way, what about no input caps at all?  I know it's not recommended, but no cap trumps a good cap, yes no?

[markC]

You won't find those brands @ Solen. Gr Research has Sonicaps. I use them quite a bit and have ordered several times from Danny @ GR.
Sonicraft has a minimum order to Ca. GR does not.
I also use Auricap. I like both the Auri and Sonic, but have not used either in input coupling apps. Only output and in speak x-overs. I have also used Solen in several "first run" applications.
IMO, Solen caps will get you 80%+ the way there in "not exteme high end equipment".

[poseidonsvoice]

By the way, what about no input caps at all?  I know it's not recommended, but no cap trumps a good cap, yes no?

Those input caps are there to block DC so the answer is no, I wouldn't leave them out and just put a jumper wire. The value of 2.2uf has been calculated for a specific pole frequency, or -3dB point to allow for sufficient bass depending on the input impedance of the amplifier. See here. Typically in these Tripath amps, specifically the TA-2024 designs, input capacitors between 2 uf to 4 uf is sufficient. The voltages inside I doubt are ever as high as the voltages listed on the capacitors (which are typically Bennic 100V-200V types).  I would still go with a capacitor you can afford that is the same voltage as the one you are replacing for safety until you measure it yourself. I've never had much luck with Solens, as there are capacitors that are as cheap if not slightly more expensive that sound significantly better to my ears. A design that I have seen that betters the Sonic Impact and the Trends Audio while addressing the deficiencies in each design is the Winsome Labs. This would be the amp I would get to modify. However, it is a significantly more expensive amp than the Sonic Impact although cheap in audiophile terms.

Best,
Anand.

[bassboy]

MarkC, from your reply, I infer that these are not just brand names, but HOUSE BRAND brand names available only from the manufacturer, so probably I won't find them all from cdn. sources.  Good to know.  I haven't even checked out the actual caps yet, but I'm assuming (international) shipping will be more than the caps.  If this turns out to be the case, I noticed you are "North of Toronto", so no international shipping.  Got any caps you wanna sell?

I wouldn't leave them out

Copy that.  Loud and clear.  Thanks Anand.  Over and out.

[bassboy]

Checking on shipping prices, GR Research shopping cart tells me:

Select Your Shipping Method
 

No Shipping Rates available for your shipping address

From Sonicraft.com:

a $10 handling fee for International orders in which the parts total is less than $100.

which means fees (factory handling charge, shipping, exchange, etc etc etc) will add up to 2 or 3x the price of the caps.

Obbligato caps look like about $40/pr cdn with shipping and taxes.  This is not so bad, but I'd still rather buy used (in canada) if anyone has used obbligato, sonicap or auricap caps.  Also, for $40 + cost of binding posts I could just get a gen2 sonic impact, although I don't need another amp, but you can see my point.

[poseidonsvoice]

By the way, make sure you can fit some of these 'upgraded' caps in your Sonic Impact amp!

Anand.

[markC]

Sorry, no caps for sale.
When I have ordered from GR, I type in the message box "please ship via U.S.P.S". The cost of shipping air mail is not expensive.
Parts Connexion is in Oakville, although they charge US dollars. Express post shipping for a few caps is usually about 6 bucks.
If you only need 2 caps, I'd bite the bullet and go with Auricaps. For $40 all in, you can find out first hand if it's a worthwhile venture.

[bassboy]

Thanks guys.  I need to think on this a bit.  If I'm going to spring for $40 worth of caps, I might just replace the other big fat (power?) cap and change the coils to air coil.  Not sure yet how far I want to go with this.

[DaveC113]

I had a Trends... not a bad amp for the cash, and changes do make a big difference in sound with the amp. Ultimately, I feel you'll be "chasing the dragon" though... there's better amps out there and the Trends/SI is never going to be really satisfactory compared to other alternatives. I replaced the Trends with a 6550 SET amp (Simple SE kit) and I like it far, far better than the Trends. You might be able to spend a few bucks on, say a Wima MKP cap or similar... I did have luck with replacing the ps caps and input resistors. I changed the resistors from 20k to 68k to increase the input impedance to better match my preamp, if you do you can reduce the value of the input coupling caps too, use 1/(2*pi*r*c) to figure corner freq... You might be able to stuff some Kiwame resistors in there for inputs to warm up the sound a bit... Search diyaudio, the Kiwames are available as a regular brand for less cash too, I forget the which brand they are off the top of my head. I also got a linear regulated ps for the amp through a local surplus store, that helped a lot too. 

[NagysAudio]

Bassboy, the Philips MKT polyester capacitors sound the best, IMO. They are cheap, but in that type of circuit they are superior. If you really want the best sounding capacitors, use the Vishay MKT1822, they are also of the metalized polyester design. You can buy the Vishay's at www.mouser.com

[whubbard]

Norbert,

You seem to have been recently going around and telling everybody here on AC to stop buying 'audiophile' parts because its all hype. That is a valid argument that can be made, but it cannot be made when you are selling a $600 1 Meter interconnect. You are the worst of the so called 'hype'. If you think that a capacitor can't sound different, then how can you possibly dare say a wire can. There are different leads in the capacitors, so even at that level one capacitor should sound better.

It has been VERY well documented that many Teflon caps sound better, and get this, it has actually been measured to show the difference in a Teflon cap.

Would you mind showing the measurements of your wire vs some good blue jean cable? I don't think measurements mean everything, but if you can measure the difference, you can most likely hear the difference.

-West

p.s. Please stop posting messages with just period marks in them, or btt. They are useless and hurt my eyes.

[NagysAudio]

First I want to say that Blue Jeans Cable makes absolutely terrific cables! Great prices too.

As for measurement, just look at the frequency the coax cable can transfer. The higher the frequency, the higher quality the cable is.

Blue Jeans Cable uses high quality industrial Belden coax, it transmits up to 3GHz.

I use aerospace/precision instrumentation (NASA, submarines, fighter jets) coax cable. My cables can transmit 30-50Ghz signals.

[*Scotty*]

I am not sure that the frequency response capabilities of a particular cable are any guarantee of it's suitability for audio applications.  Category 6a operates up to frequencies of 550MHz
but I don't think I am going to rewire my system with it even though it's only fifty cents a foot in bulk.
Scotty

[markC]

IME, I have found that I do not like the sound of polyester caps in the output coupling position. Every piece of gear that I've had that used them,  I've switched to polypropylene.
These experiences have been with source components, and each time, (well O.K only 3), there has been a marked improvement in the sound quality. A less obscured, less muddy presentation, if you will.