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

A Loftin-White style SE with EL34
A Loftin-White style SE with EL34
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 28th January 2019, 11:45 AM   #11
matejsirk is offline matejsirk  Slovenia
diyAudio Member
 
Join Date: Mar 2008
A Loftin-White style SE with EL34
My version of LF with Choke load from 2017: GU15 SE amp prototype

and my PushPull version: 6C4C in PP (Loftin White)

Both are one of the best sounding amps I have heard ever. Now I am planing to build PP version with 300B tubes.
  Reply With Quote
Old 28th January 2019, 11:46 AM   #12
matejsirk is offline matejsirk  Slovenia
diyAudio Member
 
Join Date: Mar 2008
A Loftin-White style SE with EL34
Default and schemtics:

C4D4652A-D11B-48C0-8599-87ED99135164.pngEAE33B57-C310-4997-8A91-B7ECED1752EE.png
  Reply With Quote
Old 28th January 2019, 01:51 PM   #13
BJosephs is offline BJosephs  United States
diyAudio Member
 
Join Date: May 2011
Location: Bridgewater Ma, USA
That's good to hear. How long have they been in service? It looks like you derive your -Vgk from the voltage drop across the inductor's DCR. The preamp is running at 8.6mA so you have a ~24v drop from the GU15T's cathode to it's grid. Did you have to tune R9? Where did you buy your inductors?
  Reply With Quote
Old 28th January 2019, 02:10 PM   #14
matejsirk is offline matejsirk  Slovenia
diyAudio Member
 
Join Date: Mar 2008
A Loftin-White style SE with EL34
Hi, I did not tune R9. Somehow it works good from begining. GU15 is in service for about 300 hours and 6C4C for 30 hours.

Chokes are from there: Anodendrosseln, Choke 62.15 - Anodendrossel 150H / 600H, bis 20/10mA, ca. 3000/12000 Ohm 130 / 55 pF.
  Reply With Quote
Old 28th January 2019, 11:14 PM   #15
6A3sUMMER is offline 6A3sUMMER  United States
diyAudio Member
 
Join Date: Jun 2016
A very large percentage of today's circuits (or variations and combinations thereto) were invented before world war II by Bell Labs, RCA, Western Electric, GE, etc.
  Reply With Quote
Old 29th January 2019, 04:38 AM   #16
PRR is offline PRR  United States
diyAudio Member
 
PRR's Avatar
 
Join Date: Jun 2003
Location: Maine USA
> invented before world war II by Bell Labs, RCA, Western Electric, GE, etc.

Or earlier by independents. Even a Zoologist.
Attached Images
File Type: gif Mu-amps-1933.gif (101.9 KB, 281 views)
  Reply With Quote
Old 29th January 2019, 05:15 AM   #17
6A3sUMMER is offline 6A3sUMMER  United States
diyAudio Member
 
Join Date: Jun 2016
PRR,

Good printed example. Thanks!

A lot of leading research and development was also done by Radio Amateurs.

Then there was Mr Heil, the inventor of the Heil air motion tweeter. He had plans for an FET, but it was before there was the solid state technology to support it. His on-paper FET was before Bell Labs came up with the Point Contact Transistor.

"Those who do not know the history of early inventions are bound to repeat them." (stolen and re-worded by me)

Last edited by 6A3sUMMER; 29th January 2019 at 05:18 AM.
  Reply With Quote
Old 29th January 2019, 11:09 AM   #18
BJosephs is offline BJosephs  United States
diyAudio Member
 
Join Date: May 2011
Location: Bridgewater Ma, USA
Quote:
Originally Posted by matejsirk View Post
Hi, I did not tune R9. Somehow it works good from begining.
Itís nice when things work out!
  Reply With Quote
Old 6th February 2019, 11:05 PM   #19
BJosephs is offline BJosephs  United States
diyAudio Member
 
Join Date: May 2011
Location: Bridgewater Ma, USA
Just quick check in: chokes are about a week or so away. Once I have them Iíll pick a day to solder up my prototype.
  Reply With Quote
Old 9th March 2019, 03:15 PM   #20
BJosephs is offline BJosephs  United States
diyAudio Member
 
Join Date: May 2011
Location: Bridgewater Ma, USA
Ok! Prototype is done! Pictures attached. Sounds nice so far but I’ll do some more demanding listening test today. Currently there is no feedback and the e88cc cathodes are unbiased. I’m running the outputs cool for now too, about 20W.
Attached Images
File Type: jpg 7F73ADFD-6E4B-467B-9EF0-96DAEAA264CD.jpg (1,001.4 KB, 156 views)
File Type: jpg 422FE813-2BDA-476E-8824-040875B029E3.jpg (1,000.2 KB, 152 views)

Last edited by BJosephs; 9th March 2019 at 03:19 PM.
  Reply With Quote

Reply


A Loftin-White style SE with EL34Hide 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
Loftin-White 5u4 Tubes / Valves 45 20th September 2013 06:49 AM
loftin white 801 amp Sheldon Tubes / Valves 27 18th April 2011 05:24 PM
Loftin-White Mod 5u4 Tubes / Valves 3 28th February 2006 02:21 AM
Loftin-White 5u4 Tubes / Valves 4 8th January 2006 08:27 PM
Definitely NOT a Loftin-White!! kianbach Tubes / Valves 7 14th April 2005 05:46 PM


New To Site? Need Help?

All times are GMT. The time now is 02:10 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki