Go Back   Home > Forums > > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubelab Discussion and support of Tubelab products, prototypes and experiments

Reply
 
Thread Tools Search this Thread
Old 24th April 2020, 04:57 AM   #721
w5jag is offline w5jag  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Arkansas
UX-245 is the globe envelope. CX-345 is the Cunningham globe. After a point, all the Cunningham tubes were made by RCA.

So, yes.
__________________
Win W5JAG
  Reply With Quote
Old 30th April 2020, 04:49 PM   #722
carlman14 is offline carlman14  United States
diyAudio Member
 
Join Date: Sep 2019
I am thinking about trying something a little different for my TSE-II 45 build, and I wanted some opinions. I am thinking about implementing a rectifier switch, so that the circuit would be optimized for either a 5AR4 or 5U4G depending on the selection of the switch. I'm thinking I can achieve this with a 270-250-0-250-270 PT and a 20H 216 ohm choke from Transcendar.

The selector switch would be 2 decks, 2 poles, 2 positions: The first deck would be for the different C4 caps needed. The connections for C4 on the PCB would go to the common terminals of the selector switch, and the two different capacitors (47uf for 5AR4 and 33uf for 5U4G) would be connected to positions 1 and 2 respectively. The second deck would have the PT HV connections on the PCB connected to the common terminals of the switch, then the two secondaries (2x 250V lines for 5AR4, and 2x 270V lines for 5U4G) would be connected to positions 1 and 2 respectively.

Modeling this with PSUD, I can get around 290V with either rectifier if I use the 270-250-0-250-270 PT and the 20H 216 ohm choke.

So, I have a few questions about this:

1. Would this even work? It looks like it would, but I have little experience and I wanted some else's opinion.
2. Are there any other modifications needed to the circuit other than switching the C4 capacitor? I've seen people talk about thermistors and current limiters, but there doesn't seem to be one consensus on how to use those with the 5U4G in this amp.
3. If this works the way I think it does, would the same concept work for a 45/2A3 switch? Maybe have OPT's with 3k and 5k primaries, and switch between them to optimize for each type of tube?

I appreciate any feedback or advice on this.
  Reply With Quote
Old 23rd May 2020, 12:57 PM   #723
csample is offline csample  United States
diyAudio Member
 
Join Date: Apr 2017
Location: Wisconsin
After a 14 year run, the TSE must DIE!
Default Are Remote Mounted Tubes a Problem?

I originally built a 300B TSE-II in an enclosure (Pesante 5U from diyAudio store), and it got too hot inside so I added the quietest fan I could find, but the fan is still to loud for me. I would like to rebuild the amp in a more traditional fashion (tubes and transformers on an aluminum plate with wood base) and I was wondering if using chassis mounted tube bases and wiring back to the board is asking for trouble or if it is a nonissue. Anyone have thoughts or experience with this?

Thanks!
Attached Images
File Type: jpg Remote Valves Top View.JPG (114.6 KB, 250 views)
File Type: jpg Remote Valves ISO.JPG (79.7 KB, 240 views)
  Reply With Quote
Old 23rd May 2020, 02:56 PM   #724
Evenharmonics is offline Evenharmonics  United States
diyAudio Member
 
Join Date: Apr 2007
Quote:
Originally Posted by csample View Post
Anyone have thoughts or experience with this?
I don't have a direct experience but during my online conversation with Tubelab years ago, he cited a case of one builder who did that. The issue that came up was the length of cables connecting those tubes and other components starting to affect the capacitance level too much.

As for the heat build up inside, you may just need more vent openings on your amp.
  Reply With Quote
Old 23rd May 2020, 04:07 PM   #725
Tubelab_com is offline Tubelab_com  United States
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
The rectifier tube could be mounted just about anywhere....but your picture shows it in the worse possible place. The rectifier tube will see several hundred volts of AC and create short charging pulses at the peaks of the line voltage sine waves that are rich in harmonic content. It should be kept away from the 5842's, their wiring, and the input wiring to avoid hum. Note that the power transformers 5 volt winding does not actually need to run to the PCB since it only goes to the rectifier tube.

The 300B's can be relocated slightly, but their wiring must be kept short. Keep them as close to the board as possible.

The 5842's will oscillate if looked at funny due to their high GM and near infinite load impedance. Many DIYers have decided that 5842's D3A's and the like are too sensitive to be wired in a PTP fashion, and successful efforts require trial and error.

It seems that you want a symmetrical look, so try this. Leave the 5842 tubes on the board, but place the large components (big caps, heat sinks...) on the back side so that the board can be located close to the top plate. Pull the board up closer to the front of the chassis and push the choke back nearly touching the power transformer so that the 5AR4 can go between the 300B's, over the board between the 300B socket areas if needed.

Note, I haven't actually measured it up for fitment yet.....just an idea.
__________________
Tubelab, I blow stuff up so that you don't have to.
  Reply With Quote
Old 23rd May 2020, 04:16 PM   #726
brl0301 is offline brl0301
diyAudio Member
 
Join Date: Dec 2019
Quote:
Originally Posted by csample View Post
I originally built a 300B TSE-II in an enclosure (Pesante 5U from diyAudio store), and it got too hot inside so I added the quietest fan I could find, but the fan is still to loud for me. I would like to rebuild the amp in a more traditional fashion (tubes and transformers on an aluminum plate with wood base) and I was wondering if using chassis mounted tube bases and wiring back to the board is asking for trouble or if it is a nonissue. Anyone have thoughts or experience with this?

Thanks!
Why not just build it with the standard board layout with heatsinks and caps on the bottom side of the board? You can have the sockets and tubes protruding through the top plate.
  Reply With Quote
Old 23rd May 2020, 04:23 PM   #727
Duke58 is offline Duke58  United States
diyAudio Member
 
Join Date: Jan 2009
Quote:
Originally Posted by brl0301 View Post
Why not just build it with the standard board layout with heatsinks and caps on the bottom side of the board? You can have the sockets and tubes protruding through the top plate.
I was thinking the same thing.

Why reinvent the wheel?

But, it is DIY...
  Reply With Quote
Old 23rd May 2020, 04:34 PM   #728
csample is offline csample  United States
diyAudio Member
 
Join Date: Apr 2017
Location: Wisconsin
After a 14 year run, the TSE must DIE!
Quote:
Originally Posted by brl0301 View Post
Why not just build it with the standard board layout with heatsinks and caps on the bottom side of the board? You can have the sockets and tubes protruding through the top plate.
Thanks for asking this question. I am trying to use the board I have already built which has all the components on the top side of the board. I think I can get the existing sockets off the board by carefully cutting each pin and then desoldering them one at a time. The other reason is that I didnít like the generic sockets I used on the original build and I want to use some higher quality machined tube sockets that donít match the pin spacing on the board.
  Reply With Quote
Old 23rd May 2020, 04:39 PM   #729
brl0301 is offline brl0301
diyAudio Member
 
Join Date: Dec 2019
Quote:
Originally Posted by csample View Post
Thanks for asking this question. I am trying to use the board I have already built which has all the components on the top side of the board. I think I can get the existing sockets off the board by carefully cutting each pin and then desoldering them one at a time. The other reason is that I didnít like the generic sockets I used on the original build and I want to use some higher quality machined tube sockets that donít match the pin spacing on the board.
makes sense. I would not want to have to remove and reinstall that many components either. I think like George said your biggest issue is going to be the 5842 being mounted off the board. How about leaving them mounted on the board inside the chassis and remotely mounting the 300B and 5ar4? That should get the majority of the heat out of the chassis and prevent you from the potential oscillation issues.
  Reply With Quote
Old 23rd May 2020, 05:38 PM   #730
Mr_Zenith is offline Mr_Zenith  United States
diyAudio Member
 
Mr_Zenith's Avatar
 
Join Date: Aug 2009
Location: KC Metro
After a 14 year run, the TSE must DIE!
Hi csample. George's idea sounds like a good plan if you still want to go that route.

I used to embrace symmetrical layouts when I began building DIY electronics (amateur radio and audio) in earnest some 20+ years ago. As I've acquired more experience, the technical and aesthetic merits of asymmetrical layouts have become more and more apparent, and I've since become a huge fan of them. Most of this was spurred on by the Tubelab designs and some others, perhaps most notably Poindexter's Musical Machine. All of these have proven that a well-executed asymmetrical amp can be quite elegant.

Regarding heat buildup in the chassis, my experience with the TSE-II has shown that the major culprits are the power transformer (particularly the Hammond 27X-series I'm using), the heatsinked components (filament regulator, CCS chips, driver transistors) and power resistors. Paradoxically, the tubes themselves aeren't really a big contributor. Use mongo heatsinks, provide plenty of convective cooling (i.e. lots of strategically-placed holes), and you'll be fine. I'd even posit that a move away from the Pesante chassis may be a step back in terms of overall conductive dissipation, but I don't know your amp like you do.

I've attached a picture of the 2A3 TSE-II I built last year. The chassis is made of maple and aluminum, and measures 12" x 12" x 4". Despite its small size, radiant and conductive heat from the tubes is a non-issue.
Attached Images
File Type: jpg Panel_F.jpg (695.8 KB, 180 views)
__________________
"People hate anything well made, you know. It gives them a guilty conscience." - Sir John Betjeman

Last edited by Mr_Zenith; 23rd May 2020 at 05:41 PM. Reason: Odd even.
  Reply With Quote

Reply


After a 14 year run, the TSE must DIE!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
DIY'er of the Year! CanAm Man Pass Labs 2 2nd January 2015 10:26 PM
Happy New Year..."Happy New Year" to all . Best Wishes and God Bless Albert Walfie Fixer The Lounge 12 1st January 2012 11:02 AM
Baaa...New Year same as the Old Year T in AZ The Lounge 36 7th January 2010 09:06 PM
xp20 year oct 08/xp20 year 2009 GUSTAV1966 Pass Labs 2 12th December 2009 04:26 PM
Best New Year Yonnat Pass Labs 0 1st January 2004 11:02 AM


New To Site? Need Help?

All times are GMT. The time now is 09:23 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki