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 9th November 2008, 10:39 PM   #1
diyAudio Member
 
diesel_tech's Avatar
 
Join Date: Dec 2006
Location: Sterling, CO
Send a message via MSN to diesel_tech
Default using #47 in p-p

Its been awhile since i've posted. But winter is here now.

I've been wanting to use a couple, ore even a quad of #47'S in a simple amp. I've found Gary pimm's, but the end schematic looks way to over complicated. It doesn't have to have perfect frequency respnse. Just has to sound good when using a CD player to drive it. Looking for something simple. Any ideas?
  Reply With Quote
Old 9th November 2008, 11:33 PM   #2
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Dude,

A look at the type 47 data sheet suggests that "El Cheapo" style circuitry will work.

To keep #47 grid leak resistance low and 12AT7 LTP gain high, insert IRFBC20 source followers that are DC coupled to the 'T7 anodes between the LTP and the "finals".

You choose between self and "fixed" bias.

Don't forget to regulate #47 g2 B+ with a stacked VR150/VR105 setup.
__________________
Eli D.
  Reply With Quote
Old 10th November 2008, 12:06 AM   #3
diyAudio Member
 
diesel_tech's Avatar
 
Join Date: Dec 2006
Location: Sterling, CO
Send a message via MSN to diesel_tech
Lamens terms please, i'm new to using solid state stuff, and pretty much all the audio terms.
  Reply With Quote
Old 10th November 2008, 12:29 AM   #4
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Quote:
Originally posted by diesel_tech
Lamens terms please, i'm new to using solid state stuff, and pretty much all the audio terms.

You have mail.

LTP = long tailed pair, which is a phase splitter derived from a differential gain block.

The IRFBC20 is an enhancement mode MOSFET. As forward bias is necessary, DC coupling to a preceding vacuum anode is very easy. Read MOSFET Follies.

Please notice that the IRFBC20 has a low and stable reverse transfer capacitance. That's the crucial parameter in determining suitability for voltage follower service.
__________________
Eli D.
  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



New To Site? Need Help?

All times are GMT. The time now is 07:30 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