Modification of 300B SE Amplifier - 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 24th August 2012, 03:27 AM   #21
diyAudio Member
 
Join Date: Feb 2011
Quote:
Originally Posted by palmas View Post
Best solution:
remove both srpp (I'm not a big fan), use the 6SN7 ground cathode single triode with 400V plate voltage, 22kOhm plate resistor and the 1,5k cathode resistor bypassed with a film cap of 8 to 10uF.
This has much lower gain (14x) than the product of both srpp, can take high signal at input and can provide all swing needed to drive the 300B, and will sound much better than the origínal project.

If you can make it simpler why make it worst?
Thanks and really a good idea. I will do the trial tonight.
Just to clarifiy your direction is make both stages with a single triode. The input valve with 15k plate resistor / 1.5k cathode (8uF bypass); the driver stage with 22k plate resistor / 1.5k cathode (8uF bypass). Is that correct?

Thanks again!
  Reply With Quote
Old 24th August 2012, 09:32 AM   #22
palmas is offline palmas  Portugal
diyAudio Member
 
Join Date: Jun 2007
Nop, from the two stages you make only one with a single 6SN7, using the cathode resistor from the 1st stage (1,5kOhm) and a plate resistor of 22kOhm ( minimum 5W).
I'll draw it for you if I get the time today.
  Reply With Quote
Old 24th August 2012, 09:47 AM   #23
palmas is offline palmas  Portugal
diyAudio Member
 
Join Date: Jun 2007
The 300B part you can use as it is on your schematic
Attached Files
File Type: pdf 6SN7 300B.pdf (8.2 KB, 35 views)
  Reply With Quote
Old 24th August 2012, 04:31 PM   #24
diyAudio Member
 
Join Date: Feb 2011
I did an initial trail tonight.

Instead of remove all the SRPP but I keep it at the driver stage as of. I just changed the input stage to one triode with

- 15k ohm Rplate (310Vdc) and keep the 1.5K ohm at cathode (11Vdc), for some reason it does not work at all. No signal go to the driver stage.

- I have then changed the Rplate to 74K ohm (154Vdc) and keep the 1.5K ohm cathode (5.4Vdc).. the same problem of no signal at all.

I just not sure what is the problem or may be the connection error... I have to check it again tomorrow.
  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
Recommended 300B SE Amplifier Designs gaborbela Tubes / Valves 35 22nd March 2013 02:49 AM
Mono 300B SE Amplifier JPS64 Tubes / Valves 43 22nd May 2011 03:25 PM
FS: Golden Tube Audio SE-300B II Special Edition Valve Amplifier coh-b-pyky Swap Meet 1 24th April 2010 08:31 PM
An intriguing 300B SE-direct-coupled-amplifier Antonio Tucci Tubes / Valves 27 8th February 2006 09:34 AM
For Sale - 300B SE Amplifier ThorstenL Swap Meet 0 26th June 2003 07:37 PM


New To Site? Need Help?

All times are GMT. The time now is 05:24 AM.


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