#26 pre amp

[Original Burnedfingers]

Just finished purchasing Rod's regulator boards.

I believe I will use some regulator VR tubes for my HV B+. Looking at Coolzero's power supply diagram it shows he used a CCS before his regulator tubes.

Suggestions would be appreciated for the CCS as I have zero experience here.

[Rod Coleman]

HV CCS is fairly easy to build using IXYS 10M45 and Supertex DN2540 in cascode.

Just using another DN2540 instead of the parallel 10M45 will be fine in case of the 6 to 10mA #26 circuit.

Example circuit:

Cascode CCS idea

The unlabelled resistor network takes values according to the current you need, from the curves in the DN2540 datasheet, or from other's suggestions, eg:

DN2540

IXYS and Supertex parts are available at Mouser.

[Original Burnedfingers]

Rod,

Do you have a board available for this?

[mogliaa]

This simple gyrator performs beautifully. I tested it with 4P1L, 01a, 30, 46, 112a and 26. Better performance and sound if connected as mu follower

4P1L DHT Line Stage

Happy new year to all!
Cheers,
Ale

[zigzagflux]

Originally Posted by Original Burnedfingers

Rod,

Do you have a board available for this?

You could contact K & K Audio - Lundahl Transformers, audio DIY kits and more for kits

[iko]

Originally Posted by mogliaa

This simple gyrator performs beautifully. I tested it with 4P1L, 01a, 30, 46, 112a and 26. Better performance and sound if connected as mu follower

4P1L DHT Line Stage

Happy new year to all!
Cheers,
Ale

Better than using the choke or output/it transformer?

Happy new year chaps!

[mogliaa]

In my opinion I do prefer the OT (LL1660 and filament bias). However, the mu-follower gyrator is very close to it.
Haven't done yet a side by side comparison 26 OT against gyrator version which I will do in the near future.

Ps: I'm still trying to recover from last night!
Cheers,
Ale

[Original Burnedfingers]

Ok, trying to make a CCS plate load

Could you please tell me if I'm on the right track?

2) DN2540's

[Rod Coleman]

Joe, CCS circuit looks OK with DN2540

1K gate stoppers can be 220 Ohm to 1K or so.

[Original Burnedfingers]

I'm going to post my power supply and my line stage chassis schematic in the hope that you guys in the know will look at it and tell me if I'm on the right track to start working on it.

The power supplies will be dual chassis dual supplies and the line stages will also be dual chassis. My reasoning is this... I would like to construct something without any cross talk and or noise.

The power transformers are an ebay purchase $20 Ea plus shipping. These will recitfy at 335VDC with #80 rectifier. They have no center tap so I added diodes also.

The filament transformers I purchased 30 yrs ago and I have about $12 in each of them. I have some mega 1500/450vdc 525vdc surge (Mallory)

I like the look of VR tubes so I incorporated (2) of them also.

The CCS plate supply is to be made up of two cascoded DN2540's. Schematic is on a prior post. Had sent an email to K&K Audio in the hope of purchasing two printed circuit boards with parts and heat sink. Received an email stating that they no longer use the DN2540 and the IXYS sounds better. See post 1488 for CCS plate supply. Added CCS to attached files.