#26 pre amp

[coolzero]

Thanks for the tip about alkaline batteries. I assume you mean disposible rather than rechargeable? Like the common Duracell types?

Kevin recommends one battery per channel.

andy

Yup. disposbles are better than rechargables I beleive. I use the Eveready Energizers in my pre and they are pretty stable and last long. It is almost an year for my pair of batteries.

 

[merlin el mago]

@coolzero
Where can I buy the tubes & sockets? Where can buy R-Cores for PSU? how much will be aproximately the total cost?

Thank you

Felipe

 

[merlin el mago]

Bump

 

[merlin el mago]

Bump

 

[nicoch58]

my suggestion is Thomas Mayer he can supply a full kit if you want the top....and kit



better if compatibile 26&10y ,filament bias







.

 

[merlin el mago]

Please could you give me the link?

 

[nicoch58]

Can be useful for the resistor bias use the light bulbs like on Pass delite amp?

http://www.diyaudio.com/forums/pass-labs/153832-pass-delite-amp-baf-3.html#post1963927

 

[coolzero]

@coolzero
Where can I buy the tubes & sockets? Where can buy R-Cores for PSU? how much will be aproximately the total cost?

Thank you

Felipe

Sorry Felipe, I didn't check the thread for last few days to reply. Anyhow, just replied to the message you sent to me. Hope it helps.

 

[mach1]

Coolzero, you wrote:

I tried few of different types but Alkaline came to top comparing the sonics.

Have you tried lithium batteries?

 

[merlin el mago]

Sorry Felipe, I didn't check the thread for last few days to reply. Anyhow, just replied to the message you sent to me. Hope it helps.

Yes it helps, thank you again.

 

[merlin el mago]

my suggestion is Thomas Mayer he can supply a full kit if you want the top....and kit



better if compatibile 26&10y ,filament bias







.

Thanks for the link, no doubt is very good kit, but it's also ultra expensive.

 

[coolzero]

Coolzero, you wrote:



Have you tried lithium batteries?

No. I couldn't find something suitable.

 

[regal]

For a 26A-71A linestage are there any suitable 1:1 interstage transformers with the reqired high primary impenance and inductance for the 26?

 

[Vinylsavor]

Hi!

Thanks for the link, no doubt is very good kit, but it's also ultra expensive.

Well, 2 chokes per filament and a high quality power transformer and output transformer don't come cheap

Even myself I only apply filament bias to my cost no object preamps. If budget is a concern I rather use regular cathode bias, instead of a solid state regulated filament supply. But tastes are differnt, this is just my opinion,

Best regards

Thomas

 

[Vinylsavor]

Hi!

For a 26A-71A linestage are there any suitable 1:1 interstage transformers with the reqired high primary impenance and inductance for the 26?

If you want the best, use Tango NC20. If on a budget and 1:1.125 is ok, use Lundahl 1660

Best regards

Thomas

 

[nicoch58]

HI Thomas nice to see here ,I read all post on AA about filament bias....

Can I ask if for 10y driver stage IT is good 400v/25ma or better lower Vak and up to 30ma ? (I know is not so simple

thanks

 

[Vinylsavor]

hi!

Can I ask if for 10y driver stage IT is good 400v/25ma or better lower Vak and up to 30ma ? (I know is not so simple;

It depends on the current capability of your driver stage. If you use Tango NC20. Run it at 15-20mA.

If you want to drive say a 845 which needs large grid swing, go to as high b+ as possible

Best regards

Thomas

 

[nicoch58]

thanks !

Btw 300Bxls and Tribute IT 30ma 80H

 

[Vinylsavor]

Hi!

I'd say around 400V B+ and choose a op point which will give the maximum possible voltage swing. Check the plate curves and draw in your op point there. This way your driver stage has the best possible headroom

Best regards

Thomas

 

[vgeorge]

Just finished a 26 pre. B+ is with LCLC to SSHV to an LL1667 25mA choke at 150V on anode. Cathode resistor is 1.8K bypassed by a 1000uF capacitor.
Thinking to move to battery bias soon.
Heating is with Rod' s regulators.
Also thinking to use a LL1660 wired 4.5:1 for line out. Should I use the 5mA or 10mA version? Right now I have about 6mA. Also would it be better or not to keep the anode chokes?