Cornet1 questions from a new owner

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Sarchi

Cornet1 questions from a new owner
« on: 14 Apr 2011, 06:01 pm »


That's an original CORNET.  Not built by factory.  Uses 30k pulldowns on output cathode follower instead of CCS.

jh

Jim et al,
I'm very happy with the Cornet1 I picked up last month, I've already done a bit of tube rolling and will do some more, especially the 12AU7 and the rectifier (I really like the Sovtek 12AX7LPS, inclined to stick with 'em through any short-term changes).

My questions are;
 - Is there any option to do a CCS on the Cornet1?  I'd need a walkthrough, I'm terrible with schematics.
 - What are some good choices nowadays as far as better capacitors.  Mine has Auricaps in the C5/C6 position, but in past experimenting I wasn't all that crazy about Auricaps.  I have local access to Jupiter and Mundorf caps at Partsconnexion.  I can't afford to sell the farm though.  Anyone out there try either of these in a Cornet1, or the Sonicaps?  Was it worth it?
 - Any issues with using a GZ32 or GZ34 in the Cornet1?
 - I've been using a tube integrated (Onix), but I'm picking up the Paramour 2A3 power amps soon, and was thinking I'd run my sources into a stepped attenuator (the TCJ, 20k passive option).  Do you foresee any issues?  I seem to have plenty of gain using an Ortofon 2M Red (5.0 mV I believe), so if impedances match all I should "need" is some attenuation.  Right?

Are there any other important mods/upgrades I should plan on?  Shielding the tubes..?

Thanks a lot,
Noam





Tone Deaf

Re: Cornet1 questions from a new owner
« Reply #1 on: 14 Apr 2011, 08:51 pm »
Mine's the same board but with CCS.  I've got a copy of the original manual somewhere if no better guidance is forthcoming on here, if I can follow it anyone can!  I'll scan it tomorrow in case you need it.

Apart from the CCS mine is stock, no fancy parts under the hood.  It has 1uf hovland musicaps for coupling, they replaced auricaps but I can't say I noticed any great improvement.  I'm also using 12ax7lps with a mullard ecc82.   I've used GZ32 without problem by the way, quite like it in fact. 

galyons

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Re: Cornet1 questions from a new owner
« Reply #2 on: 14 Apr 2011, 09:52 pm »
Caps are really personal taste.  Metalized polypro caps are, to my ears, too harsh and bright, including the fancy Mundorfs which just add some oil to the mix.

I use PIO caps, (Russian and/or Vitamin Q types), for signal and prefer Panasonic THSA, ED or EE lytics, depending on value, for the PS.  The NOS PIO's are musical, true to instrumental timbre and provide world class imaging and soundstaging.  And...the significant added benefit of being relatively cheap. I will also bypass with Russian teflon caps in the T series, not the K series.

The Panasonic lytics are very low noise and ripple, competing well, IMO, with the old Balckgates without the break-in, cost and availability issues.

There is a great deal of commentary on this circle, for C2, that will give you many opinions. IMO the recommendations are equally applicable to the C1.

Cheers,
Geary
« Last Edit: 15 Apr 2011, 05:13 pm by galyons »

Bernie

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Re: Cornet1 questions from a new owner
« Reply #3 on: 15 Apr 2011, 04:11 pm »
Geary, would you share as to where one can purchase Panasonic THSA, ED or EE electrotlycs.
Thanks in advance.

Bernie.

galyons

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Re: Cornet1 questions from a new owner
« Reply #4 on: 15 Apr 2011, 04:57 pm »
Geary, would you share as to where one can purchase Panasonic THSA, ED or EE electrotlycs.
Thanks in advance.

Bernie.

I order them from DigiKey.  www.digikey.com

Sarchi

Re: Cornet1 questions from a new owner
« Reply #5 on: 15 Apr 2011, 05:02 pm »
Thanks a lot for the cap comments Geary, much appreciated.

ToneDeaf: does the CCS consist of the MJE340 & heat sink?  Or is there more to it.  I don't see these in the pic of my Cornet, but they're on the original Cornet manual Jim has posted. ( http://www.hagtech.com/pdf/cornet.pdf)  Jim mentioned that I have 30k pulldowns instead of CCS, but I'm not quite sure how to interpret that.  :|

Tone Deaf

Re: Cornet1 questions from a new owner
« Reply #6 on: 15 Apr 2011, 08:13 pm »
There is an earlier manual for the board you and I have.  I've PM'd you my email address, get in touch & I'll send you a copy. 

From the manual:

Another dramatic upgrade is to put constant current sinks on the output cathode
followers. These circuits replace the R18 pulldown resistors. Add Mouser heat sink
#532-592502B34, transistor #511-MJE340, capacitor #140-XRL10V470, two each. Also
add two more 220 ohm resistors and four 910 ohm resistors.

and also:

The active current sink circuit replaces R18. There are component locations placed on
the circuit board to solder these parts directly. They are unmarked, so follow the photo
guide below. Mount transistor so the metal side is against the heat sink.
 
And there's a photo to show you exactly what to put where.

GRD

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Re: Cornet1 questions from a new owner
« Reply #7 on: 15 Apr 2011, 10:58 pm »
The CCS is worth the time to add.  I tried the resistor first and then added the CCS just to see the difference.  It made a big difference - the sound seemed more "locked down". 

Sarchi

Re: Cornet1 questions from a new owner
« Reply #8 on: 16 Apr 2011, 04:03 am »
Thanks a lot for clarifying this, TD. (and for the offer of the manual)

I'm all about the dramatic upgrade!   :thumb: