hybrid common cathode amplifier? - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th January 2003, 06:46 PM   #1
diyAudio Member
 
Join Date: Jul 2002
Location: usa
Default hybrid common cathode amplifier?

Have any of you tried this?

2 triodes, cathodes direct coupled to a MAT-02 device(dual matched bipolars), the MAT-02 share an emitter resitor to a -15 v supply (Allen Wright?).

The grids of the triodes are biased for the MAT-02 device and a.c. coupled to ground.

both plates have same values for plate resitor, however one is a.c. coupled to ground.

read if interested (it is interesting!):
http://www.glass-ware.com/tubecircui...lifiers_3.html
for more info on common-cathode amplifiers

what I'm trying to do is use this as a microphone input amplifier, balanced to unbalanced (next stage would be an eq circuit).

so, this is kind of a grounded grid amplifier, but kind of a common-cathode as well (?).

Could this circuit possibly work well? (Sorry, I can't try it - no power supply at the moment).

Thanks for any info!

-Matt Mitchell
  Reply With Quote
Old 13th January 2003, 10:43 PM   #2
halojoy is offline halojoy  Sweden
On Hiatus
 
Join Date: Nov 2002
Default Draw a Circuit! Please.

I was at your lnik.
Nowhwere I found the mic-pre-amp
using the low noise MAT-02

So, You have no Drawing of the Circuit
you think about.
Makes it Hard or Imppossible to Discuss.
---------------------------------------

My solution is, Exclude the tubes,
and use low noise Bipolar Transistors,
Will get more High Fidelity and less trouble in construction.
----------------------------------

If you want Tube sound , with distortion.
Use your Hi-Fi recordings,
but add that distortion with Tubes
when your PLAY your material.

If you add distorsion form the beginning,
then you have no choice later.

Choice between Hi-Fi or Tube-distortion.

/halojoy - waits to duscuss, til you present your idea
in a better way - with at least a principal Schematic
  Reply With Quote
Old 13th January 2003, 11:51 PM   #3
diyAudio Member
 
Join Date: Jul 2002
Location: usa
OK, sorry about that. Here is there circuit I was talking about. I have no idea if this will work (no values really, just the basic idea)

Thanks!!

- matt mitchell
Attached Images
File Type: gif commoncathodehybrid.gif (4.5 KB, 727 views)
  Reply With Quote
Old 14th January 2003, 12:39 AM   #4
diyAudio Member
 
Join Date: Dec 2001
Location: Earth
looks like a cascode long tail pair( differential input)stage ala allen wright style. which comprise of both grounded grid for top stage and common cathode for bottom stage.
can work for balanced to unbalanced or vice versa
best part about this circuit is u can apply feedback to the tube grounded to ground thus allowing the other tube to just to do the voltage work.
i think allen uses this work his pp1 amp but is configuration is for unbalanced to balanced(push pull)
  Reply With Quote
Old 14th January 2003, 01:20 PM   #5
halojoy is offline halojoy  Sweden
On Hiatus
 
Join Date: Nov 2002
Default hybrid common cathode amplifier?

Quote:
Originally posted by mwmitchell
Have any of you tried this?

2 triodes, cathodes direct coupled to a MAT-02 device(dual matched bipolars), the MAT-02 share an emitter resitor to a -15 v supply (Allen Wright?).

The grids of the triodes are biased for the MAT-02 device and a.c. coupled to ground.

both plates have same values for plate resitor, however one is a.c. coupled to ground.

read if interested (it is interesting!):
http://www.glass-ware.com/tubecircui...lifiers_3.html
for more info on common-cathode amplifiers

what I'm trying to do is use this as a microphone input amplifier, balanced to unbalanced (next stage would be an eq circuit).

so, this is kind of a grounded grid amplifier, but kind of a common-cathode as well (?).

Could this circuit possibly work well? (Sorry, I can't try it - no power supply at the moment).

Thanks for any info!

-Matt Mitchell
thanks Matt

Sorry that I personally knows so little about tubes.
But in this circuit MAT-02 transistors
are setting the performance, while the tubes
are cascoding and providing an output.
Will you use FEEDBACK?
Attached Images
File Type: gif commoncathodehybrid.gif (4.5 KB, 642 views)
  Reply With Quote
Old 14th January 2003, 01:49 PM   #6
diyAudio Member
 
Join Date: Dec 2000
Location: Germany
Default hybrid

Nothing more than a differential cascode, will work.
Reinhard
  Reply With Quote
Old 14th January 2003, 05:04 PM   #7
diyAudio Member
 
Join Date: Jul 2002
Location: usa
I would use feedback if it helped the circuit out sonically. Can you tell me more about how I would use feedback here? the grounded grid?

Also, can anyone tell me how this circuit rates as a balanced to unbalanced conervter?

Thanks for all of the help everyone!

matt mitchell
  Reply With Quote
Old 14th January 2003, 10:32 PM   #8
halojoy is offline halojoy  Sweden
On Hiatus
 
Join Date: Nov 2002
Default mwmitchell

I would think it is a Good circuit
WITHOUT the TUBES

I am not so sure about the good of feedback here
or how to make it.

/halo is somewhat confused by this idea
  Reply With Quote
Old 14th January 2003, 10:55 PM   #9
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Quote:
Originally posted by mwmitchell
I would use feedback if it helped the circuit out sonically. Can you tell me more about how I would use feedback here? the grounded grid?
Don't use feedback, it doesn't need it. I use exactly this circuit with an MAT02 and 6DJ8 for a 300uV phono cart. It's very linear and gives about 60dB of gain and sounds stunning. You'll need a buffer line driver for the output. One of the simpler VSE circuits will do, as would a simple common cathode differential with an output transformer like a Lundahl LL1660.
Allen Wright uses them as mic preamps too, and so will I eventually for the Studer tape machine I'm building.
Quote:
Also, can anyone tell me how this circuit rates as a balanced to unbalanced conervter?
Never done it, but I expect it's quite good, just make sure that both outputs see the same load, and just tap off one for the phase you want. You still need the buffer as the output Z of a cascode is quite high.
  Reply With Quote
Old 14th January 2003, 10:57 PM   #10
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Default Re: mwmitchell

Quote:
Originally posted by halojoy
I would think it is a Good circuit
WITHOUT the TUBES
Huh?
It's an excellent circuit. Period.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
how to reverse signal for Common Cathode circuit sam8888ysl Tubes / Valves 23 23rd November 2007 10:34 PM
Mu-follower vs common cathode w/- active load jnb Tubes / Valves 7 24th June 2007 09:53 AM
Common Cathode Resistor D0Hbert Tubes / Valves 1 4th March 2005 11:42 AM
cmrr of common cathode metebalci Tubes / Valves 14 21st August 2004 07:25 PM
Help with common-cathode circuit. JoeBob Tubes / Valves 48 1st March 2003 10:57 PM


New To Site? Need Help?

All times are GMT. The time now is 03:16 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2