Cornet3 Prototype

Bill Epstein · « **Reply #20 on:** 14 Dec 2009, 06:09 pm »

Guys, I took my first baby steps in building from a schematic with this power supply designed by
Steve Brown for my Aikido pre

It's not that difficult to build from a schematic when you have the parts in hand and help on the cellphone

The Cornet power supply is there for the taking and easily plugs into the board at the B+ cap. Just be extra careful 'cause B+ is a lot hotter than AC mains!

roger15ohm · « **Reply #21 on:** 15 Dec 2009, 01:00 am »

Jh,

It was a surprise to me yesterday that the Cornet 1/2kit arrived. I never expect such prompt delivery to my place with no barrier. Thanks again!!

I am now struggling weither to follow Cornet2, or to challenge Cornet3. Was full of funny idea, cut the board, external the psu but yesterday all things change

. The board was huge, and awesome.

tubesforever · « **Reply #22 on:** 15 Dec 2009, 11:13 pm »

Hey Bill,

I would bread board the Power Supply next time around if Jim doesn't decide to do a dedicated choke based power supply for the C3.

I prefer PCB to point to point. There is a physics related reason that takes too much time to put down at this time.

Bill Epstein · « **Reply #23 on:** 16 Dec 2009, 12:22 am »

Tubes, see the discussion on AA SET where Frihed asks for Phenolic boards and Steve Brown mentions Audio Note using some phenolic impregnated boards for point-to-point thru hole on their level 10 stuff.

Audio Note Kits has been doing this for awhile, running wires thru the PCB holes to connect components instead of the board traces. I like it, have come to hate solder terminals and turrets. Spend for top line, nickel free components then solder them to scrap iron-base metal tags

tubesforever · « **Reply #24 on:** 17 Dec 2009, 02:41 am »

Here is a 1993 patent abstract regarding why a pcb board is quieter than a point to point.

I believe I also have come across papers from MIT and other Universities where they measure noise in the signal with multiple layer boards.

I believe this is one reason why the Hagermans are quieter than any other components I have in my system. His dual boards place the signal within thousands of an inch proximity to the grounding plane.

"A multiple layer printed circuit board and a method of manufacturing multiple layer printed circuit boards to effectively provide a sandwich arrangement within a Faraday Cage. Electromagnetic emissions radiating from an outside surface of either the top or bottom shielding layer are substantially reduced. "

The other papers I have read do not include the aspect of the "Faraday cage" They simply show that when a low level signal travels in close proximity with its ground plane, that the signal exhibits lower noises in all cases.

I can confirm this with the Hagerman boards without question. I am extremely pleased with the noise floor level. Jim did a great job specing the boards.

Cheers!

roger15ohm · « **Reply #25 on:** 18 Dec 2009, 12:23 am »

Hai guys,

Planing to buy the resistors soon and need some advice. Brand availability in my place, Takman (cabon or metalfilm), Kiwame(cabon), TKD(metalfilm), and common type(cabon). I want to go for one off, and not to resolder 40 of them i n and out avoid damage the board. What type of resistors works the best accordingly for Cornet2:

-B plus.
-Signal path.
-Cathode.
-filament?

many thanks

Bernie · « **Reply #26 on:** 18 Dec 2009, 05:56 am »

A good choice for a one of is PRP metal film or
Riken Olm carbon film. All purchased from the: partsconnexion.com
Be sure to measure every resistor before installing.

Bernie.

Bill Epstein · « **Reply #27 on:** 19 Dec 2009, 01:27 am »

Quote

Be sure to measure every resistor before installing.

Shouldn't they all be the same length?

tubesforever · « **Reply #28 on:** 19 Dec 2009, 02:44 pm »

I would recommend Vishay Nudes in the direct signal path and kiwami's everywhere else. I would use a Mills wire wound for the H+ step down resistor.

Texas Components trims the Vishays so you can order from them and save a few bucks.

I am using a Russian Teflon 0.10uf cap at the incoming signal cap position, and using them to also bypass every B+ electrolytic and the final coupling cap. I like the Mundorf silver in Oil for that final output cap position.

Enjoy the ride. You will love the sound. Its simply amazing.

roger15ohm · « **Reply #29 on:** 19 Dec 2009, 11:08 pm »

Thanks for the tips. PRP looks great and real affordable price. No free delivery here!! ha. How about the RIAA? is silver mica good enough? As know RIAA is equally important.

regards,

Wan

Bill Epstein · « **Reply #30 on:** 20 Dec 2009, 03:17 am »

I've built the Cornet RIAA with the standard Digikey, all Kiwame, and a mix of Kiwame and PRP with Auricaps and a combination of Kimber caps and Jantzen Z-cap Superiors. Everything made a difference but the basic Hagerman sound was still there. After all, the circuit is above all else.

Just today, I finally got around to by-passing the Jantzen Z-cap Superior output caps of both my Cornet2 and Clarinet with Mr. Tubes recommended Russian teflon .01 FT-3's. I place a lot of stock in first-impression-right-out-of-the-box and the difference these caps make is not subtle. During a couple of hours of listening I heard changes in tonality as a result of break-in but the punchiness of percussion and plucked or bowed strings is constant along with rock solid imaging of instruments and voices in a more real scale and position than with the Z-caps alone. Indeed, I was about to give up on the Zs; now I feel their defects are immaterial.

You'll want to be caerful with the length and routing of the wires if you by-pass. My first scheme yielded an audible rushing noise, I changed positions and shortened the leads, now the Cornet/Clarinet is back to dead silent up past 12 O'clock on the volume control.

roger15ohm · « **Reply #31 on:** 20 Dec 2009, 04:08 am »

Bill.

Nicely finish. Can't wait to step further for my kit! That case having a Carinet is not a bad idea too. You mention about PRP resistors? I didnt' see any in the Cornet and Clarinet? Yah, most important is to have the basic Hagerman sound. This is my most concern.

I'd seen most of Cornet owner use Kiwame. My last upgrade on my Dyna st70 VTA board was also feed with Kiwame. So this time I plan to go for a change, using metal film. Local retailers serve either Takman, or TKD, which i think is abit costly plus some of the parts are not available and I still have to source somewhere. Since the delivery cost is reasonable from overseas like partconnexion, I really don't mind to wait 2 more weeks.

Bernie,

According to the PRP resistors lenght, (0.6 inch) is it too long to mount properly on the board? This should be my prime choice. I like the finishing to look great too.

Tubesforever,

Well I fancy great caps but the M-cap silver oil is not cheap in such value! Luckily I'd left some 0.1uf Russian teflon from my ex- Quad II. Oh dear i wonder how much it will cost to finish this phono. ha.

Thanks to all,

REgards,

Wan.

Bill Epstein · « **Reply #32 on:** 20 Dec 2009, 04:24 am »

Yah, the PRPs are in the Tubelab Simple SE, my mistake.

You see the long white lead on the right hand by-pass cap of the Clarinet, how it loops under the can cap? I forgot to move it and, guess what, the right channel has the almost subliminal 'rush' noise, the left channel does not. Have to go back and fix that, lead dress is so important.

I just finished listening to the real Blood ,Sweat and Tears, Child is Father To The Man and I have to say I have never heard it sound so good. I've owned a copy of this album since it came out and heard the group with Al Kooper at the controls in a small club back in '68 or '9 and know the sound better than almost anything in my collection.

15Ohm and other first time builders, you're in for a treat!

Bernie · « **Reply #33 on:** 20 Dec 2009, 04:51 am »

The PRP's should fit on the board with ease.

Bernie.

roger15ohm · « **Reply #34 on:** 20 Dec 2009, 05:24 am »

Bill,

I heard building a phono is real deal. Very sensitive and lot of failure compare to pre amp. Really have to consider properly for placing parts. Thanks for the tips. At least something to blame in future if mine finish with noise. haha.

I don't have much choice here for chassis building. Since i don't have a hammond trans, surely it wouldn't look good following the original plan by mounting upwards. That case I want to build the whole thing in chassis. Will it cause any humming, or increase in noise if i solder the parts(resistors and caps) on the otherside of the board?

Bernie,

thanks!!! That is it. Resistors-PRP. I wonder why lots of expensive branded amp don't use good parts.

regards.

tubesforever · « **Reply #35 on:** 20 Dec 2009, 07:22 am »

While I agree that a lot of gear has cheap parts, has anyone looked inside a Boulder 30k phono preamp or inside a BAT fully differential phono preamp?

They have 1000's of dollars of high quality parts. Hell inside a Mark Levinson mono block amp you will find 3,000 dollars worth of power supply.

The Boulder uses Kiwami's and that's one big reason why I use them too. The nude vishay idea came from my engineering friend who used to listen to whales digestive tracks at 150 miles distance from his nuclear submarine.

That's the level of resolution the nude Vishays bring to the table.

The rule of thumb for manufacturer's selling to a dealer network is that they need to mark up their total cost 300 to 400 percent. The dealer marks it up 40 to 50 percent. So 1,000 dollars of parts and pieces will retail no less than $4200 dollars and often for about 5 to 6k dollars.

Bill I am glad you are trying those Teflons. The sound quality is rediculous. A US version teflon would sell for about 175 dollars per cap. I think these things sell for around 4 dollars a piece on ebay.

I am trying some Russian silver mica 0.001uf caps for the top RIAA position and will be running about 0.055uf caps for the lower eq cap. So far so good. The bass is definitely back with just a little added uf. For those that bought my K40Y9 PIO caps you can parallel a 0.0068uf silver mica pretty cheap. I bet this is all you will need for some deeper richer bass lines. I can get some 0.0068 silver micas reasonably priced for anyone that wants to try them.

Cheers!

roger15ohm · « **Reply #36 on:** 20 Dec 2009, 03:25 pm »

Great info, tube.

Just confront with some problems. Half way buying the resistors and realize they don't have 1 watt 910.

These resistors for R203, R210, R218 and R215.

Can i use 1/2 watt for these?

Or, replace with 1k?

Or, series 2 1k8?

Thanks,

Wan.

Bernie · « **Reply #37 on:** 20 Dec 2009, 10:21 pm »

For the 910 ohm resistors you have listed, half watt will work fine in those places. If you are really bothered, by the wattage, you can use the Kiwami 2 watt resistors. They work really great as a cathode resistor. R203 and R210 are bothode resistors.

Bernie.

Bernie · « **Reply #38 on:** 20 Dec 2009, 10:25 pm »

Pardon my typeO at the end, I meant to say, they are both cathode resistors.

Bernie.

roger15ohm · « **Reply #39 on:** 21 Dec 2009, 12:38 am »

Bernie,

That case i will buy 1/2 watts for these resistors. Really if the cathode, which some said has to be higher voltage bothers me, I can just replace locally. Now I like all in red. Thanks alot!

regards,

Wan.