Cornet2 completed

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miter53

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Cornet2 completed
« on: 18 Feb 2008, 08:13 pm »
I finished up my Cornet2 and I am absolutely delighted. Upgrades were:

Kiwame resistors
Mills wirewound power resistor
Sonicaps @ C200 and C206
Mundorf silver/oil @ C208
Russian FT-3 Teflon @ C203
Vampire gold plate RCA's

I burned in the FT-3's and the Mundorfs for over a week hooked up to a SS receiver with a 10 ohm resistor in series. I'm using Sovtek 12AX7LPS, a Brimar 12AU7 and vintage GE 5Y3. Assembly went pretty painlessly, other than screwing up the drilling on the back panel. Plugged it in and all voltages checked out and it sounded great immediately. Its dead quiet, the bass is extended and very strong, midrange and highs balanced and very liquid sounding. I may try rolling some other new production 12AX7's or sell some stuff to finance a couple of Tele 12AX7's, put it sounds pretty darn good as is. I'll try to get some photos up in a day or two.

Thanks for a great kit design, Jim.

Mike
« Last Edit: 26 Feb 2008, 05:03 pm by miter53 »

miter53

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Re: Cornet2 completed
« Reply #1 on: 19 Feb 2008, 11:12 pm »

miter53

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Re: Cornet2 completed
« Reply #2 on: 19 Feb 2008, 11:13 pm »

miter53

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Re: Cornet2 completed
« Reply #3 on: 19 Feb 2008, 11:13 pm »

hagtech

Re: Cornet2 completed
« Reply #4 on: 20 Feb 2008, 12:37 am »
If you're going to spend that much on coupling caps, you should upgrade the EQ caps too (47nF, 1nF).

jh

PatOMalley

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Re: Cornet2 completed
« Reply #5 on: 20 Feb 2008, 08:50 pm »
miter53, is that the vinyl clad aluminum for the Lansing elclosure?

miter53

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Re: Cornet2 completed
« Reply #6 on: 20 Feb 2008, 09:59 pm »
I sprayed the top plate with Hammerite. I like the look and it gives it a little more visual interest, I think. I did the same with my Bottlehead Foreplay III. Plus, truth be told, since I drilled the top rather than use a punch, there were some small scratches in the black finish from spinning aluminum shavings.

PatOMalley

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Re: Cornet2 completed
« Reply #7 on: 20 Feb 2008, 11:36 pm »
great idea. That will hide the dust nicely, too.

tubesforever

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Re: Cornet2 completed
« Reply #8 on: 25 Feb 2008, 11:26 pm »
Those FT-3 caps are the bomb.  Very expressive, very dynamic, and when they break in they are completely transparent.  Right now they might be just a tad edgy sounding but that will go away.  My C2 has such awesome dynamic capability it seems like listening to a high res digital product.

Great job.

BTW 8 Russian FT-3 teflon 0.10uf caps run about 6-7 dollars each.  I am using them just at C208 on mine, but I plan to order some more and try them at some other bypass positions.  This is perhaps the best value in a bypass cap given its huge sonic improvement.

Jim?  Would you have any personal recommendations for the other small value coupling caps?  Silver mica?

hagtech

Re: Cornet2 completed
« Reply #9 on: 26 Feb 2008, 05:14 am »
I'm not a fan of the silver mica.  Some folks like what polystyrenes do.  For me, I get maximum results with foils, not films.  So I went to expensive foils for the new HAGLABS stuff.

jh

klamka

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Re: Cornet2 completed
« Reply #10 on: 26 Feb 2008, 08:32 pm »
 Cool
I'm not so lucky with my 100db + Klipschorn bass bins. There is still low level hum  (little more in one channel that the other ). I used tube sockets with the screens ,took gray ground wire out of transformer  twisted filament wires etc . I guess most of reports on "dead quiet " comes from people using 89-90db speakers ;)
Maybe  the TVC as a pre is a cause although my other DIY pre (J-fet Borbely) -is dead quiet but has some issues with sibilants . I built my Cornet using Hammond (alu ) chassis (major PITA), dale 2W resistors , mika and A-note film/foil on RIAA , Hovland coupling caps (2uF on output ). The voltages are 5%-10% and filament little low 5.8V .Regards, L

marchewd

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Re: Cornet2 completed
« Reply #11 on: 28 Feb 2008, 07:40 am »
Jim,
    If I build my C2 with the same values as the original poster, what caps would recommend for the EQ caps?  Also, what are their designation on the board (ex. C2??).  Finally, where you can get the T-3 caps?  Ebay?

Thanks,
Dan



If you're going to spend that much on coupling caps, you should upgrade the EQ caps too (47nF, 1nF).

jh

BobM

Re: Cornet2 completed
« Reply #12 on: 28 Feb 2008, 01:16 pm »
I just picked up a quartet of these Russian teflon's also. They are breaking in right now on a burner. I hope to try them out as a bypass on my phono stage, as well as a bypass on my speaker's tweeter crossover cap.

Yes, they are inexpensive and there's lots of them available on e-bay. Hopefully they will meet the hype, performance wise, and not the (cheap) price?

Enjoy,
Bob

miter53

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Re: Cornet2 completed
« Reply #13 on: 28 Feb 2008, 04:34 pm »
The EQ caps are C202 & C204. I've ordered Sonicaps and Relcap RTE's to try in those spots.

hagtech

Re: Cornet2 completed
« Reply #14 on: 1 Mar 2008, 07:47 pm »
Quote
I'm not so lucky with my 100db + Klipschorn bass bins

Actually, the sensitivity of your loudspeakers matters not.  It is only important with regards to the noise floor of the power amplifier.  The noise floor of phono or linestage results in a certain system SNR.  The loudspeaker sensitivity does not enter the equation.

For example, let's say you like listening at 100dB spl.  And your phonostage had an SNR of 60dB.  If your linestage and power amplifier are much better than this (say 80dB each), then virtually all noise is generated by phono.  The audible noise floor is then 40dB spl.  It is about SNR, not S. 

This is a very common misconception. 

jh

klamka

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Re: Cornet2 completed
« Reply #15 on: 2 Mar 2008, 02:36 pm »
Thanks Jim  :duh:
It means I don't have to live with the problem and time to take apart my Cornet again. (And again kick myself for being greedy and ordering Hammond chassis ) .I will also run separate ground from my Rega tonearm. So far it sounds smooth and colorful and I have no complaints.
Regards, L

hagtech

Re: Cornet2 completed
« Reply #16 on: 2 Mar 2008, 10:56 pm »
With sensitive speakers, it is the noise floor of the power amp that counts.  It must be very quiet.  You can't turn it down. 

For source components like a phonostage, set the volume to a nice listening level.  Then, lift the arm.  You should not hear anything except for maybe a faint hiss from your listening chair.  Ideally.

jh

marchewd

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Re: Cornet2 completed
« Reply #17 on: 4 Mar 2008, 02:39 am »
Jim,
      Would I be able to get away with using a 0.001uf 400v cap in C204, instead of the 630v cap spec'ed?

Thanks,
Dan

hagtech

Re: Cornet2 completed
« Reply #18 on: 4 Mar 2008, 08:30 pm »
Yeah, you can go as low as 250V there.

jh

marchewd

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Re: Cornet2 completed
« Reply #19 on: 4 Mar 2008, 08:35 pm »
Jim,
    Great!  I found some NOS VitaminQ caps for these locations, but the 0.001 caps were only rated @400v.

Thanks again,
Dan