CCS for small signal pentodes

ask your general tube related questions here

CCS for small signal pentodes

Postby DeathRex » Wed Jan 11, 2017 5:50 pm

I was thinking of using a 717A as a small signal amplifier, (I haven't worked with small signal pentodes) but gain depends a lot on the anode resistor. If I wanted high current I would need a low resistance and I would get low gain. If I wanted gain of 100 - 200 I would need a 100Kohm or higher resistor. It seems a perfect place for a DN2540 - LM334Z CCS (I haven't worked with CCSs either). Has anyone tried them together>

You can look at 6AK5s data sheet for curves.
At first I wanted to be a ET. Now I are one.
User avatar
DeathRex
KT88
 
Posts: 1014
Joined: Wed Nov 18, 2009 8:13 pm
Location: Cortez, CO

Re: CCS for small signal pentodes

Postby Geek » Wed Jan 11, 2017 7:39 pm

I'd use a cascode bipolar. Pair of MPSA92, couple red LED's and a pair of resistors. Better load impedance than both, superior PSRR than single DN2540 and the LM334 isn't good above 40V.

Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia

Re: CCS for small signal pentodes

Postby DeathRex » Wed Jan 11, 2017 7:46 pm

I was thinking about cascoding them like Shannon shows here

Except I would run it at about 5ma, cause peak current is 10ma.
Last edited by DeathRex on Tue Jan 17, 2017 10:37 am, edited 1 time in total.
At first I wanted to be a ET. Now I are one.
User avatar
DeathRex
KT88
 
Posts: 1014
Joined: Wed Nov 18, 2009 8:13 pm
Location: Cortez, CO

Re: CCS for small signal pentodes

Postby Geek » Thu Jan 12, 2017 3:54 am

That's a good idea :))
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia

Re: CCS for small signal pentodes

Postby DeathRex » Thu Jan 12, 2017 9:50 am

To use a DN2540 and LM334Z as a source, would I need a gate stopper resistor for the DN2540? Would that be the only change?
At first I wanted to be a ET. Now I are one.
User avatar
DeathRex
KT88
 
Posts: 1014
Joined: Wed Nov 18, 2009 8:13 pm
Location: Cortez, CO

Re: CCS for small signal pentodes

Postby Geek » Thu Jan 12, 2017 1:01 pm

Always use a gate stopper.

Nothing will change, since you're working with DC.
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia


Return to tube 101

Who is online

Users browsing this forum: No registered users and 3 guests

cron