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 2nd May 2009, 01:58 AM   #1
w5jag is offline w5jag  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Arkansas
Default 46 and the Tubelab SE

Type 46 is a 5 pin tetrode that when triode strapped is a fine single ended DHT amplifier, as pointed out in the prior 12AT7 / 46 thread.

With a suitable base adapter, 46 and VT-63 is easily useable in the Tubelab SE. Prefabricated adapters are commonly available on Ebay.

Compared to a 45, the 46 biases differently, but the Tubelab SE has sufficient range to easily accomodate this tube. It takes a little more heater current, and has almost twice the amplification factor of a 45.

I set mine (VT-63) to about 275 volts and 20 mils. I started at about 25 mils, but decided that was a little hot, so I backed it off to 20 mils.

Although less powerful than a 45, they sound like a more powerful tube than 45, maybe because of the amplification factor.

Win W5JAG
  Reply With Quote
Old 2nd May 2009, 02:13 AM   #2
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: South Florida
307A / VT225 also works in triode with an adapter. I think that it makes a better 300B than a 300B does. I really need to hear them in P-P. I am working on that one.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 2nd May 2009, 09:11 PM   #3
diyAudio Member
 
Steve Cresswell's Avatar
 
Join Date: Apr 2006
Location: Yorkshire UK
Default Re: 46 and the Tubelab SE

Quote:
Originally posted by w5jag
T
Although less powerful than a 45, they sound like a more powerful tube than 45, maybe because of the amplification factor.

Win W5JAG
Yes I've noticed that the 46, despite its lower power than the 45 is a much more solid and beefy sounding tube. Full of life but subtle at the same time.

Steve
  Reply With Quote
Old 2nd May 2009, 10:26 PM   #4
diyAudio Member
 
korneluk's Avatar
 
Join Date: Jan 2005
Location: South Florida
Quote:
Originally posted by tubelab.com
307A / VT225 also works in triode with an adapter. I think that it makes a better 300B than a 300B does...
From a private email exchange with Pete Millet, here are the suggested 307A/VT225 op points:

1) 5k load, and ~300V plate voltage, -30V grid bias (or the equivalent self-biased), ~40-50mA Ip. If you want more power you can push up to 350V or so at 50mA without any problems.

2) For lower output, run B+ of ~280-300 and a 680 ohm cathode resistor, with a load of about 5k.

Enjoy,
  Reply With Quote
Old 3rd May 2009, 12:38 AM   #5
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: South Florida
Quote:
If you want more power you can push up to 350V or so at 50mA without any problems
I settled on 360 volts and 60 mA with those big blue Edcor 5K transformers. Pete ties G3 to G2 and plate, I have it grounded.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 18th May 2009, 02:25 PM   #6
w5jag is offline w5jag  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Arkansas
Quote:
Originally posted by tubelab.com
307A / VT225 also works in triode with an adapter.
About a half dozen Ken-Rad VT-225's followed me home from Dayton, so I hope to give them a try soon, unless I'm out of 4 pin bases. I completely forgot to pick up any more of those.

Win W5JAG
  Reply With Quote
Old 18th May 2009, 02:47 PM   #7
w5jag is offline w5jag  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Arkansas
Quote:
Originally posted by tubelab.com

Pete ties G3 to G2 and plate, I have it grounded.
With only 4 pins to work with, I figured I would tie G3 to the cathode, like a 47, unless there is a compelling reason to do otherwise.

I'm at the lake listening to 47's in a Tubelab SE right now, so I know this confguration works OK in it.

Win W5JAG
  Reply With Quote
Old 18th May 2009, 07:26 PM   #8
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: South Florida
Quote:
About a half dozen Ken-Rad VT-225's followed me home from Dayton
I was at Dayton this year. I only bought 10 tubes (I really am trying to cut back). I got a 4500 VCT 150 mA transformer for $5, and a partially built power supply containing a very large 550-375-0-375-550 volt at 300 mA + several 6.3 and 5 volt windings transformer for $10 (nice cabinet too). I also got several MRI amplifier boards cheap to try as HF linear amps. I won't be back home until next weekend though.

The VT225 has a 5.5 volt filament. They seem to work fine in a Tubelab SE with 5 volts though. I was testing a pair in class AB2 P-P right before I left Florida. 30 to 35 WPC is easy but I haven't listened to them yet.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 18th May 2009, 07:52 PM   #9
w5jag is offline w5jag  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Arkansas
I have also cut back on tube buying. I need to be selling.

I got the VT-225's ($6/each) and a NOS pair of GE 6BQ6GA, and some really nice Johnson ceramic Septar sockets from Fair Radio on Thursday, together with a few other odds and ends.

At the hamfest I got a chinese 5U4G and a pair of KT66 from Stan, and in the flea market I bought a pair of 5932 ($15 for the pair); a NOS 12BV7 and 12BE6 for a buck each; and three globe 47's for $60. Unless you count TV lamps, that was it for hollow state. I did restock on caps, building hardware, and some other small parts.

I was loaded down like a pack mule with tubes last year.

I think the crowd was up this year.

Win W5JAG
  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
tubelab se DimZ Tubelab 58 20th January 2009 12:47 PM
tubelab PP? weinstro Tubes / Valves 9 25th March 2008 03:07 AM
Especially for Tubelab: 845 amp 2.0 Giaime Tubes / Valves 24 30th July 2006 03:39 PM
tubelab ethermion Tubes / Valves 24 20th July 2006 03:13 PM


New To Site? Need Help?

All times are GMT. The time now is 05:31 PM.


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