Recommend me a tube... - 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 4th November 2009, 11:00 AM   #1
Gordy is offline Gordy  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
Default Recommend me a tube...

A friend likes my 6H30 / transformer output headphone amp and has asked me to build something similar for him. However he wants the tube on display, and wants ‘a big looking tube’. He means something that looks like a 2A3 for example.

So is there a triode (or triode strapped pentode) that has the following:

Mu about 12 – 18
Internal impedance Rp of less than 2000 Ohms
Indirectly heated cathode
Physically bigger than a 6H30 (i.e. bigger than a typical 9 pin tube)
Any type of base / socket is OK

What would you recommend?
  Reply With Quote
Old 4th November 2009, 11:20 AM   #2
diyAudio Member
 
azazello's Avatar
 
Join Date: Aug 2008
Location: Bulgaria
Hi !
6S41S /6C41C Russian/!! Ri = apr. 300 ohm/!!/, mu = 16-19!!
http://scottbecker.net/tube/sheets/018/6/6S41S.pdf
Very good vision!

Last edited by azazello; 4th November 2009 at 11:24 AM.
  Reply With Quote
Old 4th November 2009, 11:35 AM   #3
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Wimps, all of you. Use a 6528.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 4th November 2009, 12:00 PM   #4
45 is offline 45  Italy
diyAudio Member
 
45's Avatar
 
Join Date: Dec 2008
Location: UK
C3m.
It's quite bigger than the 6N30.
Typically a triode connected C3m has (at 150V/ 20ma): mu = 19, Rp = 2.4 Kohm, Gm = 8 mA/V.
It's a low noise device with mesh plate!
Also is a SQ tube. It is guaranteed 10000 h if run within specs, just as the 6N30P-DR
Cheers,
45

Last edited by 45; 4th November 2009 at 12:04 PM.
  Reply With Quote
Old 4th November 2009, 12:49 PM   #5
speleo is offline speleo  Iceland
diyAudio Member
 
Join Date: Apr 2007
Location: Keflavik
How about 6AS7? Looks similar to 2A3 and no OPT needed, see this project for example:
HeadWize - Project: A Single-Ended OTL Amplifier for Dynamic Headphones by Aren van Waarde

I haven't heard that headphone amp but I did build the 6SN7/6BL7 by Eric Barbour some years ago (also on Headwize) and I really liked it. A good preamp with enough power for my 150ohm Sennheiser headphones.

speleo
  Reply With Quote
Old 4th November 2009, 12:51 PM   #6
diyAudio Member
 
Tom Bavis's Avatar
 
Join Date: Jun 2002
Location: Macedon NY
The only "affordable" G-style tube that comes to mind is the Russian 6F6G. This is a little higher Rp and a little lower mu (triode connected) than you're looking for... and then there are the Chinese 6L6s that look like mini 6550s. In GT style, 6AH4 and 6CK4 are possibilities, as is 6EM7 and the like if you need a gain stage. Of course, I'm thinking in terms of what's in MY basement...
  Reply With Quote
Old 4th November 2009, 01:13 PM   #7
diyAudio Member
 
azazello's Avatar
 
Join Date: Aug 2008
Location: Bulgaria
Quote:
Originally Posted by speleo View Post
How about 6AS7? Looks similar to 2A3 and no OPT needed, see this project for example:
HeadWize - Project: A Single-Ended OTL Amplifier for Dynamic Headphones by Aren van Waarde

I haven't heard that headphone amp but I did build the 6SN7/6BL7 by Eric Barbour some years ago (also on Headwize) and I really liked it. A good preamp with enough power for my 150ohm Sennheiser headphones.

speleo
I have the same OTL 6AS7 /6H13C Russian/ and Sen. 580 - 300 ohm, I think this is the best tube cathode follower
for OTL! Ri is aprox. 300-400 ohm. I advise You this link!
  Reply With Quote
Old 5th November 2009, 01:15 AM   #8
Gordy is offline Gordy  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
Well guys, you have provided me with a nice list of alternatives. Thank you for that, and I will investigate them all.


Can anyone think of any further recommendations that I should also consider?
  Reply With Quote
Old 5th November 2009, 05:39 AM   #9
diyAudio Member
 
Join Date: Nov 2009
E55l -10W
It's quite bigger than the 6N30.
Typically a triode connected E55L has (at 125v/ 55ma): mu = 30, Rp = 650 ohm, - best tube for headphone amp.
  Reply With Quote
Old 5th November 2009, 07:58 AM   #10
diyAudio Member
 
Join Date: Sep 2003
Quote:
Originally Posted by 45 View Post
C3m.
It's quite bigger than the 6N30.
Typically a triode connected C3m has (at 150V/ 20ma): mu = 19, Rp = 2.4 Kohm, Gm = 8 mA/V.
It's a low noise device with mesh plate!
Also is a SQ tube. It is guaranteed 10000 h if run within specs, just as the 6N30P-DR
Cheers,
45
Second that!
Remove the cover carefully to display the mesh grid. (I was corrected when I called it "mesh plate" in another post.) You will need to put a small marking on the glass to keep track of the orientation when the cover is removed. These tubes are also used in AYONs statement preamps.
I bought most of my C3ms from Frag Jan zuerst --- Ask Jan First a few years back. Also bought the rare 6.3V version, C30, before the prices took off.
__________________
Thanx!
  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
Please recommend a tube DAC to build. JayH3 Digital Source 1 26th May 2008 01:50 AM
Recommend a nice tube pre-amp for the TA-10.1? rurouni Class D 4 15th November 2007 10:30 PM
Recommend an EL84 tube for HIFI ME2 Tubes / Valves 15 13th May 2007 03:13 PM
What would you recommend? bjackson Chip Amps 0 21st November 2005 04:17 PM
What do you recommend for first DIY? Me@Home Multi-Way 10 23rd June 2002 12:04 AM


New To Site? Need Help?

All times are GMT. The time now is 01:17 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