His Master's Noise: A Thoroughly Modern Tube Phono Preamp - Page 4

21st April 2010, 12:00 PM
SY On Hiatus Join Date: Oct 2002 Location: Chicagoland	His Master's Noise: A Thoroughly Modern Tube Phono Preamp After more than 25 years of faithful service, it seemed that it might be time to redo my phono system. After all, I like to think that I've picked up a few tricks in the intervening years... The old system consisted of a VPI HW17-II, a Linn Ittok LVII tonearm, and a Troika cartridge. The Troika was... Click here to read the entire article Last edited by Variac; 2nd April 2011 at 12:17 AM.

26th April 2010

BudP

diyAudio Member

Good God Stuart.... even I, with my utter lack of objective thought process can make sense of this.

Bud

"You and I and every other thing are a dependent arising, empty of any inherent reality" Tsong Ko Pa

27th April 2010

On Hiatus

Uh-oh, I'd better reconsider...

Thanks, Bud.

"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."

20th May 2010

grufti

diyAudio Member

".... a common-mode choke will make things even better, but I just didn't have one. If you do, feel free to use it."

I stumbled across this sentence and I'm wondering whether you mean:
"... use the common-mode choke instead of the dual regulator heater supply" or else: "... use the common-mode choke with the dual regulator supply, and if so where in your heater power supply?"

Well thought out indeed!

20th May 2010

On Hiatus

"With," not "instead of." I'd put it between the raw supply and the regs.

"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."

22nd May 2010

Irakli

diyAudio Member

Very nice article, thank you.

Just a quick question: is there a sub-miniature analog of D3a/7721 you know of? I searched and could not find any. It wuold be nice to build your amp with pencil sub-mini tubes.

My System

22nd May 2010

On Hiatus

I'm not aware of any. Subminis do look cool.

"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."

5th June 2010

danielwritesbac

diyAudio Member

Wow!

Although I'm not familiar with tubes, its easy to spot that the high fidelity approach isn't tacked on but rather the high fidelity approach is integral to the design itself. That's just so graceful.

19th June 2010

Globulator

diyAudio Member

Would a pentode like a 6j51p/EF184 be a reasonable sub. for the D3a?

19th June 2010

On Hiatus

The spec sheets I have don't give much info about triode operation. It does look like the gain is lower, as is the transconductance. Since the source impedance of the first stage is critical to getting the RIAA right, you'd want to measure the plate resistance and adjust the 20k build-out resistor accordingly. For an operating point, I'd probably start with 10mA and 1.2V on the cathode.

"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."

21st June 2010

Globulator

diyAudio Member

Thanks SY, sounds like it may be worth trying then. Some triode data is here:

Tube Tester Files - 6J51P

I'm still collecting the bits - I'll post back later when I've got a bit nearer!