New Tim Mellows OTL project - Page 4 - diyAudio
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 6th February 2012, 03:13 PM   #31
djn is offline djn  United States
diyAudio Member
 
djn's Avatar
 
Join Date: Oct 2004
Location: Waterford Michigan
THanks!!! I am going to steal your design for stacking caps!!!
__________________
My "Art" website http://home.comcast.net/~djnagle/site/
  Reply With Quote
Old 6th February 2012, 05:18 PM   #32
diyAudio Member
 
Join Date: Feb 2012
Location: Tatarstan
Hi ! I just start work on same project (OTL TIM MELLOW) The big brown capacitors from Russia more better then another type?? I have some of them (I am from RUSSIA) . Thank you
  Reply With Quote
Old 6th February 2012, 08:09 PM   #33
diyAudio Member
 
Join Date: Oct 2008
Hi all,

Thanks for you comments,
I have spent hours pouring over the layout and the best way to fit it all together...

All the tubes and are to be Russian + the 0.1uf and 1uf in the audio path I have used paper in oil caps as most audio forums seem to rate them. When testing the Russian ef86 tubes in my Mullard 3-3 amp and they sounded good and perhaps slightly cleaner than the Mullards.
I will by trying both ecc83's and 6n2p's in the first stage during testing.. hopefully the Russian tubes will impress as I use the mullards in my Aikido based headphone amp.
and only have 1 spare + more made by 1 by pinnacle..

note the stickers to remind me while wiring ...diodes and cap all ways round in the -430 supply

more pics to follow in a few days.. have to go to work
Attached Images
File Type: jpg SDC13129.JPG (394.1 KB, 554 views)
File Type: jpg SDC13153.JPG (333.5 KB, 535 views)
File Type: jpg SDC13155.JPG (329.6 KB, 524 views)
__________________
Any Progress is Progress
  Reply With Quote
Old 6th February 2012, 08:23 PM   #34
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Quote:
Originally Posted by smith01793 View Post
Hi all,

Thanks for you comments,
I have spent hours pouring over the layout and the best way to fit it all together...

All the tubes and are to be Russian + the 0.1uf and 1uf in the audio path I have used paper in oil caps as most audio forums seem to rate them. When testing the Russian ef86 tubes in my Mullard 3-3 amp and they sounded good and perhaps slightly cleaner than the Mullards.
I will by trying both ecc83's and 6n2p's in the first stage during testing.. hopefully the Russian tubes will impress as I use the mullards in my Aikido based headphone amp.
and only have 1 spare + more made by 1 by pinnacle..

note the stickers to remind me while wiring ...diodes and cap all ways round in the -430 supply

more pics to follow in a few days.. have to go to work
Hi,

A few thoughts for what they are worth..

Your diodes should be sleeved the current and power stored in the PSU should not be under estimated.

Do you know how hot these tubes run? Think cooker element.

The mains power is also quite high..this may not matter, however at least you know..

Regards
M. Gregg
__________________
What is the sound of one hand clapping?
  Reply With Quote
Old 7th February 2012, 03:43 PM   #35
diyAudio Member
 
Join Date: Feb 2012
Location: Tatarstan
Quote:
Originally Posted by smith01793 View Post
Hi all,

Thanks for you comments,
I have spent hours pouring over the layout and the best way to fit it all together...

All the tubes and are to be Russian + the 0.1uf and 1uf in the audio path I have used paper in oil caps as most audio forums seem to rate them. When testing the Russian ef86 tubes in my Mullard 3-3 amp and they sounded good and perhaps slightly cleaner than the Mullards.
I will by trying both ecc83's and 6n2p's in the first stage during testing.. hopefully the Russian tubes will impress as I use the mullards in my Aikido based headphone amp.
and only have 1 spare + more made by 1 by pinnacle..

note the stickers to remind me while wiring ...diodes and cap all ways round in the -430 supply

more pics to follow in a few days.. have to go to work
Hello ! I check this type caps(on photo) on Russian forum that tru this one PIO but I have another type . MBGO(It seems like yorth) -- that one have another dielectric .It funny we are try find good audiophile capacitors from abroad . But you guys used old russian staf.That about tube .Me too I have 6n2p and E83cc from TESLA .And I want try both of them. I get two big trans from Polon Creat Kamk device. But each of them have have just one high voltage (aprox 130v) so i want use it in parallel. That you think about that?
  Reply With Quote
Old 8th February 2012, 08:44 AM   #36
diyAudio Member
 
Join Date: Oct 2008
Good Morning Gents, (and ladies !!)
I have a day of work today so I will be spending some time on the project,
Thanks again for your comments,

DJN ..a few pics of the mounting rail detail..
The anodised U section was from B&Q diy they keep various aluminium brass and steel sections on the shelf. your nearest store is about 15 mins away ....from Heathrow airport

M Gregg..
I did think about sleeving leads, but where to stop? with point to point wiring the tag strips and pins on the caps are the "high" exposed point anyway. I think I will only sleeve component leads that are close enough to short out.
Thanks for the warning but I used to be TV engineer in the 70s, the colour TVs of the time certainly commanded your respect, Like the Decca CTV25 with valve stabilised EHT (25kv) or the pye205 where the mains was fed by a 2 pin plug straight in to the power/line panel.. (they bite)
as for the heat I live in the U.K. so it will only be a problem a few weeks in the year.

Dmitry..
My plan is always to try things out for myself and see what I like the sound of in my system, you can sometimes find that the "sweet spot" is not always with the most expensive part, so give your caps a try you can always change them again.
I have used transformers in parallel before, just need to make sure you have them in phase by checking output voltage.

Pictures to follow as camera needs a charge and coffee is ready.

Tony.
__________________
Any Progress is Progress
  Reply With Quote
Old 8th February 2012, 09:19 AM   #37
diyAudio Member
 
Join Date: Oct 2008
I had planned just 1 rail for the psu caps (Samwha gold for audio as recommended by Tim) I had discarded the second as it was a rough test piece. (note the scratches) but It worked so well that I decided to go with it anyway.
as I only had 2 of the 20mm stand-offs I had to make some brackets up with washers
Attached Images
File Type: jpg rail 1.JPG (333.6 KB, 482 views)
File Type: jpg rail 2.JPG (330.0 KB, 446 views)
File Type: jpg rail3.JPG (332.2 KB, 185 views)
__________________
Any Progress is Progress
  Reply With Quote
Old 8th February 2012, 03:28 PM   #38
diyAudio Member
 
Join Date: Feb 2012
Location: Tatarstan
Hi! Thanks for notes .That is intresting way for body this type amp audio-talk :: View topic - OTL by Tim Mellow

Did you plan sort tube In pare ?
  Reply With Quote
Old 9th February 2012, 07:25 PM   #39
diyAudio Member
 
Join Date: Oct 2008
spent a few hours today on OTL project;-

1) Cap wiring done and all PSU wiring finished apart from main feed and switch.

2) All the grounds are to return to one point (star grounding) the 1.5sq mil copper may be overkill but it gave me good results on my Mullard 3-3 stereo amp

3) high precision 34k resistors (as specified by Tim) feed to the input caps, the centre earth pin on the tag strip is isolated from the metal rail using T03 transistor isolating kit parts, thus preserving the star grounding

4) I was short of a tag to connect the resistor between the bias pot and the input balance pot, after lots of head scratching came up with this.

progress is slow as I am spending more time working out the layout than soldering... but any Progress is Progress !!
Attached Images
File Type: jpg cap wiring.JPG (334.2 KB, 200 views)
File Type: jpg star grounding.JPG (326.9 KB, 173 views)
File Type: jpg input wiring.JPG (330.0 KB, 182 views)
File Type: jpg SDC13192.JPG (330.4 KB, 164 views)
__________________
Any Progress is Progress
  Reply With Quote
Old 9th February 2012, 08:05 PM   #40
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Looking good

I used High temp antex solder on my 6C33c sockets. (have you burnt the OP tubes in yet?)

I dont think the 1.5 is overkill. I use PTFE silver plated stranded 1.5mm.

And the speaker Gnd is 2.5mm from CT. (Its not a Tim Mellow)

Are your Hi prec resistors holco?

Regards
M. Gregg
__________________
What is the sound of one hand clapping?

Last edited by M Gregg; 9th February 2012 at 08:09 PM.
  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
OTL designed by Tim Mellow with 4 6C33C? dwhitf Tubes / Valves 293 9th March 2014 09:04 AM
Preamp for Tim Mellow's 6C33C OTL flanagan Tubes / Valves 3 9th November 2010 07:13 PM
Simplest 6080 or 6AS7 OTL Project? Michael Rothacher Tubes / Valves 29 26th August 2010 08:05 PM
10 - 16 ohm project for Atma-Sphere OTL amp j.burtt Multi-Way 2 8th May 2006 05:34 PM


New To Site? Need Help?

All times are GMT. The time now is 05:13 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