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

Getting 60W from 6C33C pushpull
Getting 60W from 6C33C pushpull
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 21st August 2015, 04:10 AM   #1
CijTele52 is offline CijTele52  United States
diyAudio Member
 
Join Date: Feb 2005
Location: CA
Default Getting 60W from 6C33C pushpull

Hi guys, is it possible to get 60W of power output from a pair of 6C33C? I see some designs getting 40W out from pushpull Class A. How about Class AB 6C33C with more of power output? Can anyone recommend bias point?

I'm also looking at EL509 triode mode which has Rp of 200 ohm. It may be a good alternative to 6C33C class AB because of its high peak current?

Thanks in advance for your suggestion.
  Reply With Quote
Old 21st August 2015, 08:28 AM   #2
jazbo8 is offline jazbo8
diyAudio Moderator
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Getting 60W from 6C33C pushpull
Take a look at Roessler's design, I think it can do more than 60W.
  Reply With Quote
Old 21st August 2015, 11:19 AM   #3
Junm is offline Junm  Philippines
diyAudio Member
 
Junm's Avatar
 
Join Date: Dec 2008
Location: Dau
Send a message via Yahoo to Junm
I 6 planning to post a thread for 6c33c PP on how to maximize the power it can give and here you are starting this. Thanks..

For JazBo...thanks for the link....on those people here who have tested 6CC33C PP....can this tube really make more than 60w and how about using 400ohm OPT which I have..can we got more wattage or just more distortion?
  Reply With Quote
Old 22nd August 2015, 12:13 AM   #4
CijTele52 is offline CijTele52  United States
diyAudio Member
 
Join Date: Feb 2005
Location: CA
Thanks, Jazbo8. I once tested 6W6 as driver tube and got 300Vpp with reasonably low distortion.

250V 110mA bias point for 6C33 doesn't look very linear to me I may need to add some NFB to lower distortion. Overall, I now have idea where to start.
  Reply With Quote
Old 22nd August 2015, 06:28 AM   #5
jazbo8 is offline jazbo8
diyAudio Moderator
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Getting 60W from 6C33C pushpull
Quote:
Originally Posted by Junm View Post
can this tube really make more than 60w and how about using 400ohm OPT which I have..can we got more wattage or just more distortion?
400 is tougher, does it have multiple output taps, if so, you can try putting 8R on the 4R tap for example to get the primary up to 800.

Quote:
Originally Posted by CijTele52 View Post
250V 110mA bias point for 6C33 doesn't look very linear to me I may need to add some NFB to lower distortion. Overall, I now have idea where to start.
It's closer to class B operation to get the high power output, if you want more linearity, you can increase the bias a bit and use a higher Ra load (e.g., 1.2k~1.6k).

Last edited by jazbo8; 22nd August 2015 at 06:32 AM.
  Reply With Quote
Old 22nd August 2015, 02:29 PM   #6
CijTele52 is offline CijTele52  United States
diyAudio Member
 
Join Date: Feb 2005
Location: CA
Thanks for your advice. I'll build a prototype to test power vs. distortion.
  Reply With Quote
Old 22nd August 2015, 06:33 PM   #7
jazbo8 is offline jazbo8
diyAudio Moderator
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Getting 60W from 6C33C pushpull
Looking forward to see your prototype results, which OPT you plan to use?
  Reply With Quote
Old 22nd August 2015, 10:42 PM   #8
Alastair E is offline Alastair E  Wales
diyAudio Member
 
Alastair E's Avatar
 
Join Date: Feb 2004
Location: South Wales
Looking at simulations, 250V +B, Idle at 200mA, 1000 ohms p-p, driving the grids from a low impedance source positive by about 26V will yield 71W RMS with about 4% 3H at full power in the o/p stage. For the first 15 Watts or so, it will remain in class A mode.


pk cathode-current is around 750mA, so thats not a huge issue for these valves, they'll do OTL at 2.5A on pk....

Input drive voltage needs to be around the 117V pk and I recommend MOSFET followers direct to grids.
--These big ugly Russians can start to sink grid-current while still a little negative so needs a low drive impedance....

Simulating the quoted design, you're looking at 5 -6% H3, and only 52W RMS. but this doesn't include the distortion/non-linearity you'll get as the grids near 0v and start to draw currents, and blocking-distortion as the coupling-caps charge...

Also, you'll only be in Class-A territory for 4.5W of output.

Whatever you do, make sure you burn the 6C33C's in for a few Days First--Minimum 6 hours burn in! They'll just Love to arc over if you don't, and once thats happened, the valve is stuffed--even though it may still work--it WILL arc again, and cause who-knows what damage.
__________________
Das Beste Oder Nichts

Last edited by Alastair E; 22nd August 2015 at 11:03 PM.
  Reply With Quote
Old 23rd August 2015, 03:54 AM   #9
jazbo8 is offline jazbo8
diyAudio Moderator
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Getting 60W from 6C33C pushpull
Which OPT would you recommend that's not too expensive to get in the EU?
  Reply With Quote
Old 23rd August 2015, 08:33 AM   #10
jazbo8 is offline jazbo8
diyAudio Moderator
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Getting 60W from 6C33C pushpull
Default Isn't it too hot?

Quote:
Originally Posted by Alastair E View Post
Looking at simulations, 250V +B, Idle at 200mA,
Pda idle for the above condition is 250 x 0.2 = 50W, isn't it above the 30W Pdiss limit per the datasheet (at least the one I have)? Also for class AB2 operation, shouldn't the "70% rule" be applied? i.e., Pda < 21W.

Click the image to open in full size.
  Reply With Quote

Reply


Getting 60W from 6C33C pushpullHide 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
Help 6AQ5 pushpull VMUNIX Tubes / Valves 32 30th March 2014 10:45 AM
6N11+TDA7293 60W+60W Amplifiers fn9mm Chip Amps 5 28th August 2011 12:37 PM
PushPull vs ParalelSE tinitus Tubes / Valves 14 2nd July 2010 09:39 PM
6c33c-b & 6c33c-v skybird Tubes / Valves 4 21st April 2009 06:21 AM
6C33C-EB / 6C33C-EV extended life ? ger56 Tubes / Valves 2 14th October 2007 05:54 PM


New To Site? Need Help?

All times are GMT. The time now is 11:05 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki