Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

6N6P cascode calculation
6N6P cascode calculation
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
Thread Tools Search this Thread
Old 11th September 2007, 07:09 AM   #1
croccodillo is offline croccodillo  Italy
diyAudio Member
croccodillo's Avatar
Join Date: Mar 2005
Location: Bergamo
Default 6N6P cascode calculation

Good Morning to all,

I'm trying the following circuit:
6N6P Cascode

The upper valve grid is set to about 170V, while the lower one works at about 160V.
The circuit works, but has a too low gain, for my application.
I know, from Morgan Jones book explanation, that the lower valve sees a very low load, since the upper tube has a very low internal, dynamic impedance.
My question is: How can I calculate the load impedance for the lower valve, in manner to better understand how to change the circuit (maybe a different lower valve, or a parallel of two 6N6P triodes) to suit my needs?

Thanks in advance,
Giovanni Albergoni
In Nomine Libertatis Vincula Edificamus,
In Nomine Veritatis Mendacia Efferimus.
  Reply With Quote
Old 11th September 2007, 03:45 PM   #2
jimmyd53 is offline jimmyd53  United States
diyAudio Member
jimmyd53's Avatar
Join Date: Jan 2006
Good Morning Giovanni,

Here is a copy of an email that Lukasz from the lampizator web site sent me about using the 6h6p triode in a parallel SE configuration. Hope it helps. James

I never actually built it but I think Ewgennyi has a prototype. The 6H6P can give
out even tens of miliamps. So just operate it in the highest possible operating
point (say 160 V DC power supply, via primary of transformer - on anode. Cathode
to ground. Separate circuit for bias - try minus 6,3 V adjustable with a pot. You
can steal -6,3 V from the heater circuit and make minus 4 from it. Just make
heaters with DC and ground the plus not minus. Makes no difference. then paralell
as many tubes as you desire power. Of course - paralell the halves too. Set 15 mA
per half tube. 30 mA per one paralelled triode.
the only trouble is the speaker transformer. It has to be bought somewhere. Just
remove it from old broken tube radios from 1950's or 60's.
Yoy also need gigantic power supply for the heaters - 5 watts per tube. If you
decide to use 4 tubes per channel - the heaters must be powered by 40 watts
(maybe a 100VAC transformer)

Regards and good luck.
  Reply With Quote
Old 11th September 2007, 04:56 PM   #3
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
EC8010's Avatar
Join Date: Jan 2003
Location: Near London. UK
The lower valve sees as its anode load:

(RL + ra)/(u + 1)


RL = the load resistance in the anode circuit of the upper valve
ra = anode resistance of the upper valve at the chosen operating point
u = amplification factor of the upper valve at the chosen operating point
1 = one
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote


6N6P cascode calculationHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
6N6P vs. 6N6P-I sparkle Tubes / Valves 60 13th April 2013 02:15 AM
6n6p amp timothyldodd Tubes / Valves 2 2nd October 2007 12:48 AM
6N6P cascode + 6AS7 Cathode follower croccodillo Tubes / Valves 12 15th September 2007 09:33 AM
Help with 6N6p dsavitsk Tubes / Valves 10 29th March 2007 09:34 PM
Pin 9 on 6n6P, 6H30, etc dsavitsk Tubes / Valves 3 27th August 2006 06:37 AM

New To Site? Need Help?

All times are GMT. The time now is 06:21 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio