Revision 2. Balanced - Page 3 - 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 1st April 2012, 09:02 PM   #21
BRSHiFi is offline BRSHiFi  United States
Previously known as kingden
 
Join Date: Aug 2008
Location: Evanston, IL
How is this for a driver?
Attached Images
File Type: png Untitled.png (17.7 KB, 60 views)
  Reply With Quote
Old 1st April 2012, 11:49 PM   #22
BRSHiFi is offline BRSHiFi  United States
Previously known as kingden
 
Join Date: Aug 2008
Location: Evanston, IL
Pretend the input transformer is there, I will add an updated schematic later.
  Reply With Quote
Old 2nd April 2012, 04:50 PM   #23
BRSHiFi is offline BRSHiFi  United States
Previously known as kingden
 
Join Date: Aug 2008
Location: Evanston, IL
I added on the transformer but I have a few questions regarding the impedance and the DC resistance of the coils.

I looked up the specs on the Jensen transformer and found:

- Input impedance (primary) at 1k = 14.1k.

- DC resistance of primary = 2.26k ohms.

- DC resistance of secondary = 1.9k.

The source driving the transformer will be a floating differential signal. I am a bit confused on how to configure the setup to make the input impedance 100k ohms. Should I just put a 47k ohm in series with the + and - inputs and the transformer winding? Should I tie anything to ground here?
Attached Images
File Type: png Untitled2.png (18.2 KB, 46 views)
  Reply With Quote
Old 2nd April 2012, 09:58 PM   #24
diyAudio Member
 
Shoog's Avatar
 
Join Date: Aug 2002
Location: Eire
You cannot realistically get an input transformer to give more than its rated impedance and it will have an optimal loading impedance which will prevent it from ringing. Basically whatever that loading is you are advised to apply to the secondary and that will help to define the actual impedance of the transformer - which will be somewhat no linear with frequency.
R93 & R94 are no longer defining the input impedance. Are you certain that you will be using a none centertapped input transformer - a CT one would work better.

None of this really matters to the circuit as any self respecting preamp will be able to drive an input impedance down to 10kohms and so you need to just use what is prescribed for the transformer.

As for DC impedance - this is not really relevant unless you are passing DC through the transformer - it should not effect the transformer ratio.

--------------------

As for your feedback arrangement. You have gone from a relatively straightforward ratio to ground, to a situation where the ground leg is through the other half of the differential pair cascade. This will have increased the impedance to ground many times over - so the first thing that you need to do is define the impedance up through the differential partner and back to the power supply. What might complicate the matter even more is that this impedance will probably vary with signal.

Shoog

Last edited by Shoog; 2nd April 2012 at 10:01 PM.
  Reply With Quote
Old 2nd April 2012, 10:15 PM   #25
BRSHiFi is offline BRSHiFi  United States
Previously known as kingden
 
Join Date: Aug 2008
Location: Evanston, IL
How would you change the feedback configuration?
  Reply With Quote
Old 2nd April 2012, 11:39 PM   #26
BRSHiFi is offline BRSHiFi  United States
Previously known as kingden
 
Join Date: Aug 2008
Location: Evanston, IL
So you are saying just ditch the CCS and use the transformer?
  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
EAS Controller revision A pra3718 Chip Amps 9 8th March 2011 09:31 AM
Northcreek Okara Revision Question mevaniuck Multi-Way 3 2nd July 2006 07:15 AM
Cheap 24/96 DAC, Revision B. jwb Digital Source 235 28th June 2006 08:46 AM


New To Site? Need Help?

All times are GMT. The time now is 11:26 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