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

45 Vs. VT-52: How Do They Sound??
45 Vs. VT-52: How Do They Sound??
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 12th January 2018, 03:54 PM   #1
Bruce Berman is offline Bruce Berman  United States
diyAudio Member
Join Date: May 2017
Location: Long Island, NY
Default 45 Vs. VT-52: How Do They Sound??

I am currently using a 45 tube (ST style) to drive my SE 300B output stage.

The amplifier topology is 2-stage: an input transformer provides around 24 dB of voltage gain, and drives the grid of the 45. The 45 is transformer coupled to the grid of the 300B. The input to my amplifiers are driven by a transformer volume control (TVC). Both the 45 and 300B are DC heated with constant current regulators. Loudspeakers are the Altec A-5, with the Hiraga crossover and the 1505 multicellular horns.

This system sounds wonderful (to me at least), but I am always looking for possible improvement in the sonics. I do have a number of WE and National Union VT-52s here, and I am wondering how they compare sonically with the 45.

The VT-52 is essentially a drop-in replacement for the 45, except for the filament voltage, which from what I understand is around 6.3 V. It is not easy for me to provide the 6.3 volts required to heat this tube from my existing amplifier circuitry; hence my question to the group as to how the VT-52 compares sonically to the 45, before I begin any modifications to my equipment to find out myself.

Thanks for any input!

Last edited by Bruce Berman; 13th January 2018 at 05:18 AM.
  Reply With Quote
Old 13th January 2018, 09:49 AM   #2
Rod Coleman is offline Rod Coleman  United Kingdom
diyAudio Member
Rod Coleman's Avatar
Join Date: Jul 2004
Location: Warwickshire UK
45 Vs. VT-52: How Do They Sound??
Hello Bruce,

I can't say anything about the relative sound of the two DHTs, but maybe I can help with the voltage arrangements...

The dc voltages required for 45 (2.5V) and VT-52 (6.3 or 7.0V dc ?) can be generated (including the overhead for Coleman filament regulators) with a 6.3V rms trafo, so long as it can deliver 4A rms - so ideally, rated for 6-8A rms.

For the 45, use a normal bridge-rectified dc, as shown in the manual.
For VT-52, change the rectifier arrangement to a voltage doubler.

The doubler parts are (per channel):

trafo: 6.3V 6A rms
rectifier: 2x MBR1045
capacitors: 22000F 16V snap-in type, Panasonic, Nichicon, EPCOS (reliable makers, IOW)

PSUD2 file attached. Change filename to .PSU, from .txt,
search Duncan PSUD2 if you don't have the application.
Attached Files
File Type: txt DOUBLER-6V3-6A-12V5dc.txt (198 Bytes, 35 views)
  Reply With Quote
Old 13th January 2018, 06:25 PM   #3
hooman is offline hooman  Iran
diyAudio Member
hooman's Avatar
Join Date: Nov 2008
Location: tehran
Originally Posted by Rod Coleman View Post
Hello Bruce,

I can't say anything about the relative sound of the two DHTs,

211 is dht .......... if use some tube driver like vt25 the sound can be different .why all use non dht driver ?
1979.....i lost everything
  Reply With Quote


45 Vs. VT-52: How Do They Sound??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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to mix sound from notebook and external sound card and get headphones output burence73 Headphone Systems 17 29th December 2012 07:58 PM
Creative Sound Blaster X-Fi sound card w/upgrade GOWA Swap Meet 0 12th August 2012 09:05 PM
Kicker zx700.5 sub channel has humming sound and amp2 has echo like sound ivkata Car Audio 3 10th April 2012 09:23 PM
The Ultimate Sound Improving for Compact Disc's through Patent-Pend.CD Sound Improver tiefbassuebertr Digital Source 145 25th April 2011 07:39 PM
Eighteen Sound (18 Sound) NSD 1095N Compression Drivers and XT1086 Horns opc Swap Meet 6 1st May 2009 03:48 AM

New To Site? Need Help?

All times are GMT. The time now is 10:43 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio