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 5th May 2011, 09:43 PM   #1
JPS64 is offline JPS64  Germany
diyAudio Member
 
Join Date: May 2011
Default Mono 300B SE Amplifier

Starting today.

To understand: new DHT supply (thread in this forum).

HV supply from french LED magazine.

No electrolyt capacitors (customer can choose the type).

Try to find the best choice: Mundorf, WIMA MKS4, EPCOS MKP).

CMC tube socket, AMTRANS resistor, MILLS resistor.

Power components on top side.

Reduced cabling.

Any suggestion?

Attachments: first 3D View...
Attached Images
File Type: jpg 300B_AMP_TOP.jpg (97.6 KB, 960 views)
File Type: jpg 300B_AMP_BOT.jpg (93.7 KB, 908 views)
  Reply With Quote
Old 6th May 2011, 02:02 PM   #2
JosM is offline JosM  Netherlands
diyAudio Member
 
Join Date: Feb 2008
Location: The Hague
Default SE 300B mono amp

I have build a SE 300B monoamp by myself using Sowter "potted" output transformers and Sowter powertransformers with very good experience. For my brother I have build a SE 300B monoamp using ae-europe output and powertransformers, also with good experience. Mundorf caps are well.
  Reply With Quote
Old 6th May 2011, 02:27 PM   #3
Green77 is offline Green77  Sweden
diyAudio Member
 
Join Date: May 2007
Location: MJOLBY
I just finished my 300 amp. Used Mundorf Supreme but change them to Mundorf Supreme silver/oil just for test... IMO it was a big diffrent in sound..to the better
  Reply With Quote
Old 6th May 2011, 08:35 PM   #4
JPS64 is offline JPS64  Germany
diyAudio Member
 
Join Date: May 2011
The coupling capacitor between 6SN7 and 300B is silver/oil grade. The other ones are today WIMA MKS4 and EPCOS MKP DC Link. No electrolyt capacitor for the moment.

I am try to understand the design of Rob Coleman DHT Gyrator/Current Sink for physical implementation on this board.
  Reply With Quote
Old 6th May 2011, 08:45 PM   #5
tomchr is offline tomchr  United States
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Greater Seattle Area
Schematic?
  Reply With Quote
Old 6th May 2011, 09:58 PM   #6
JPS64 is offline JPS64  Germany
diyAudio Member
 
Join Date: May 2011
This weekend the HV power supply and the heather supplies (prepared for RCs DHT Heather design).

I try to publish the schematics beginning next week...
  Reply With Quote
Old 8th May 2011, 08:46 PM   #7
JPS64 is offline JPS64  Germany
diyAudio Member
 
Join Date: May 2011
Heather 6SN7: Salas low voltage regulator?
DHT 300B: Rob Coleman DHT Heather?

Or LiFePO4 Batterie pack (16Ah) as voltage source on f+ and adapted current sink on f-?

Meanwell COTS charger allowing rapid charging!
  Reply With Quote
Old 9th May 2011, 12:49 AM   #8
kmaier is offline kmaier  United States
diyAudio Member
 
kmaier's Avatar
 
Join Date: Jul 2007
Default Deciding factors?

It's not clear what, if any, design goals you have for such an amplifier. Have you given any thought to performance specifications, i.e., s/n ratio, freq. response, output power, distortion limits, etc.... or even a circuit topology? I'm not trying to rain on your parade, but you seem to be grasping at ideas for pieces of an amplifier and see what everyone thinks will work best. Having a set of (practical) design goals seems a logical starting point, otherwise you're going down a path of "designed by committee".

Regards, KM
__________________
... just because you're paranoid, it doesn't mean they're not after you...
  Reply With Quote
Old 9th May 2011, 03:51 PM   #9
diyAudio Member
 
Palustris's Avatar
 
Join Date: Aug 2006
Location: Cape Cod
Default direct coupling is an order of magnitude better

"The coupling capacitor between 6SN7 and 300B is silver/oil grade."

If I were starting to design a new SE 300B power amp, the last circuit topology I would choose would be to cap couple the driver tube to the grid of the output tube. The very best sounding most revealing capacitor is NO cap. Don't even consider cap coupling; direct coupling is an order of magnitude better.

The reason is not just because a capacitor doesn't sound as good as no capacitor; just as important is the fact that the 300B starts to draw grid current way before the grid reaches 0V. To get the best from the 300B you have to have a low DC path to ground so that grid current doesn't upset the bias of the tube causing distortion. At the very least, if you insist on cap coupling you will need a grid choke.

I would suggest either the monkey/DRD topology or stacked supplies as in the Komuro 300B.
Attached Images
File Type: jpg komuro_300Ba.jpg (271.8 KB, 669 views)
  Reply With Quote
Old 9th May 2011, 04:14 PM   #10
tomchr is offline tomchr  United States
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Greater Seattle Area
Quote:
Originally Posted by Palustris View Post
The very best sounding most revealing capacitor is NO cap. Don't even consider cap coupling; direct coupling is an order of magnitude better.
I second that opinion. Here's my schematic: DC coupled 300B idea - request for comments

I've made tweaks since then and will update the schematic eventually. Currently, I'm working on the power supply for it. I've had it running on lab supplies and it sounds very good to my ears. You can use any high-mu triode, I just dropped a 5842 in there as I had simulation models for it. If you don't mind the lower sensitivity, you can even use a 6J5 or half a 6SN7 to drive it.

~Tom
  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
FS: Golden Tube Audio SE-300B II Special Edition Valve Amplifier coh-b-pyky Swap Meet 1 24th April 2010 08:31 PM
FS: for 300B (JE Labs 300B SE) builders cartman Swap Meet 2 29th October 2008 01:13 PM
An intriguing 300B SE-direct-coupled-amplifier Antonio Tucci Tubes / Valves 27 8th February 2006 09:34 AM
* 35 watt * 300B SE = super 300B + Class A2 rick57 Tubes / Valves 4 13th July 2005 04:18 PM
For Sale - 300B SE Amplifier ThorstenL Swap Meet 0 26th June 2003 07:37 PM


New To Site? Need Help?

All times are GMT. The time now is 08:18 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