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 8th September 2006, 04:33 AM   #1
diyAudio Member
 
Join Date: Jan 2004
Location: Minnesota
Default Simple Hybrid SE EL84 UL amp.. comments please.

thinking:

1:1 input transformer -> source follower mosfet -> 1:10 step-up -> 6 to 8 parallel EL84's SE UL.

Running 300v 39mA a piece. maybe a 600:8 output tranny.

fixed bias on output stage to secondary of 1:10.

very simple... no coupling caps.. all major voltage gain by 1:10 and output stage.

power supply: cap multiplier circuit. suggestions?

DC on EL84 filament supply.

comments? suggestions?

will this work and what should I look out for?

thanks!
__________________
It is not you... you are it.
  Reply With Quote
Old 8th September 2006, 02:00 PM   #2
rdf is offline rdf  Canada
diyAudio Member
 
rdf's Avatar
 
Join Date: Jun 2004
Location: big smoke
If it were me the first consideration is confirming a 1:10 doesn't balk at driving the grid capacitances of 8 parralled el84s. Have you considered a source follower, maybe DC coupled, to the el84 grids and using the 1:10 as the input stage? Drops one tranny, replaces it with a smaller signal, higher quality unit and the follower will better drive the output. Since you're going fixed bias you already have a negative supply handy.
  Reply With Quote
Old 10th September 2006, 11:04 AM   #3
diyAudio Member
 
Join Date: May 2005
Location: Pretoria, South Africa
I would not go to the complication of dc EL84 heater supply. If the heater wiring does not go near an input, you will certainly not get interference from 6VAC (which I presume is the reason for dc).

Regards
  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
Simple EL84 amp... Skorpio Tubes / Valves 11 3rd January 2009 08:25 PM
Tube/MOSFET hybrid results/comments/suggestions? lgo51 Pass Labs 59 22nd June 2008 04:02 PM
Simple EL84 Mas Penk Tubes / Valves 25 17th August 2006 01:55 AM
Simple AMP Comments. arte Solid State 15 26th April 2005 07:49 AM
fs/swop, el84 hybrid tube amp psychosteve Swap Meet 0 11th October 2004 02:10 PM


New To Site? Need Help?

All times are GMT. The time now is 04:35 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