His Master's Noise: A Thoroughly Modern Tube Phono Preamp - Page 30

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.

19th November 2016

billshurv

diyAudio Member

true dat!

20th November 2016

jackinnj

diyAudio Member

For an MM cartridge you can abandon balanced mode and load the grid of the D3a with ~47k.

I have the Denon DL-103, and scratch my head when I see reviewers wax poetic about carts which cost kilobucks. Your better off sticking with the Denon and investing the balance in tickets to live music.

Why, silly hare, are you fleeing from the fierce jaws of the lion now grown tame?

20th November 2016

peafarmer

diyAudio Member

Scott, thanks for the files. I just downloaded Eagle.

6L6, I have a Linn LP-12 with the Ittok LVII tonearm. I just looked up the specs, the Ittok has an effective mass of 11.5g, and accepts carts of 2-10g. Is this considered "low mass"? Sorry if this is simplistic...I'm just getting back into audio after a kid-raising hiatus.

Andy

20th November 2016

kevinahcc20

diyAudio Member

jackinj: "I have the Denon DL-103, and scratch my head when I see reviewers wax poetic about carts which cost kilobucks. Your better off sticking with the Denon and investing the balance in tickets to live music."

Precisely!

Kevin(ahcc20)...I'd rather have a bottle in front of me than a frontal lobotomy!

2nd December 2016

jackinnj

diyAudio Member

With a 1x3 Molex Header, you can select either 47k||220p or 6.8k

HMN5_Input.png

Why, silly hare, are you fleeing from the fierce jaws of the lion now grown tame?

5th March 2017

frankwilker

diyAudio Member

Hi Sy,
great Thread, thank you.

you wrote:

I'd run the first stage at 10mA, the second two at 4mA. The original values work fine, but dropping the current will extend tube life and reduce heat at no performance penalty.

How can i adjust this operating points? Need to change the CSS?

best regards Frank

6th March 2017

mrdave45

diyAudio Member

I have a couple (or so) of questions about the power transformers.

1. Main tx, is there any reason i shouldnt use a single wound secondary with just 1x250v (or whatever) on it and use a full bridge rectifier? ( i get why you need the centre tap to use just 2 diodes). Are there any advantages (apart form saving 2 diodes!) to using the centre tapped 250v-0-250v (which i think is a presumably more costly 500vct tx).

2. The article says more voltage on the raw supply is better leaving a 25v to 40v buffer for the regulators. How high is too high?

3. With regard to applying the voltage to the centre tap of the 18vct heater supply. It looks like this would produce rails of 60v+12.7v and 60v-12.7v to feed in to the heater regs.

Is this essentially a 2x9v transformer?
Im not quite sure how you would wire this.

Va
0V
Vb
0v

For a dual rail supply you would tie 0v and vb together to give ground. Is this the same as a centre tap and so you can do all the usual tricks with it?

7th March 2017

jackinnj

diyAudio Member

I sent out for some boards -- $10 for a pair. Shipping in the US $6, ROW $9. In respect of SY's IP, these are essentially being sold at cost.

They measure 8" x 2". The transformers will have to be mounted off the board -- because there are so many different varieties.

I also have some very nice Cinemag MC step up transformers.

Why, silly hare, are you fleeing from the fierce jaws of the lion now grown tame?

7th March 2017

jackinnj

diyAudio Member

Frank -- I understand that SY is taking a vacation from DIYAUDIO -- to answer your question, you can change the operating point by changing the LED, or putting a resistor in series with the LED. You'll then have to change Rset on the CCS for the current.

Why, silly hare, are you fleeing from the fierce jaws of the lion now grown tame?

13th March 2017

noviygera

diyAudio Member

SY,

For a strictly MM phono, would you still use "His Masters Noise" or go with another phono design altogether? All op-amp?
thanks,
Herman