BUILD THREAD - A New Take on the Classic Pass Labs D1 with an ESS Dac - Page 64 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

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 20th June 2013, 02:19 AM   #631
qusp is offline qusp  Australia
diyAudio Member
 
qusp's Avatar
 
Join Date: Oct 2009
Location: Brisbane, Australia
not FPE, but I have dimensions, shoot me a PM
  Reply With Quote
Old 26th June 2013, 09:35 AM   #632
diyAudio Member
 
Join Date: Feb 2005
For some time we worked on Edel Renderer - Ian's FIFO Buffalo DAC - OPC NTD1 I / V. Now everything works perfectly and I am very pleased with the sound. I am impressed by DNT1 - is something ... big! It's different from Legato. I always returned to NTD1.
A dynamic and extraordinary presence, the bass is fabulous!!!
I am very much to thank OPC for NTD1
And thanks for all the support's Qusp

Excuse my English: (
Attached Images
File Type: jpg DSCN1848.JPG (238.0 KB, 515 views)
  Reply With Quote
Old 7th July 2013, 07:13 AM   #633
diyAudio Member
 
Join Date: Feb 2005
I discovered a problem with my NTD1: (
I have a small signal output ,is not more than 0.5VAC.
Unfortunately ... I do not know what to check, my ideas finish: (
I am very grateful for any ideas.

Thank you!
  Reply With Quote
Old 1st November 2013, 10:01 PM   #634
Rolle is offline Rolle  Denmark
diyAudio Member
 
Join Date: Sep 2010
Location: Kolding
Hi

Before I get on with building a differential amplifier, I need to do the balanced to single ended conversion from OPC D1 to my SE tube amplifier. I have decided to go for a transformer solution. I have looked at sowter 3575 3575 will this one do the job for me?

I am wondering how to connect the transformer - did I get it correct in attached picture or am I completely lost here? Do I attach the transformer shield to ground on OPC D1 or ground on tube amplifier. What about the center tap (blue 5)

I used the excel sheet provided earlier by qusp to calculate output cap size to around 1,5uF-2uF (input impedance 50Kohm on tube amp). But I am wondering if this holds true, when using the transformer.

I feel a little lost here any advice really be appreciated

Thanks
Rolle
  Reply With Quote
Old 1st November 2013, 10:04 PM   #635
Rolle is offline Rolle  Denmark
diyAudio Member
 
Join Date: Sep 2010
Location: Kolding
sorry forgot to attach picture
Attached Images
File Type: jpg balse tranformer connection.JPG (25.9 KB, 312 views)
  Reply With Quote
Old 1st November 2013, 10:12 PM   #636
Nikitas is offline Nikitas  Greece
diyAudio Member
 
Join Date: Nov 2011
Location: Amsterdam
expect irritating and ironic answer from the usual suspect....
__________________
I'm that guy who finds ways *not* to do things..
  Reply With Quote
Old 1st November 2013, 11:32 PM   #637
opc is offline opc  Canada
diyAudio Member
 
opc's Avatar
 
Join Date: Oct 2004
Location: Ottawa, Ontario, Canada
Hi Rolle,

That transformer looks pretty decent, and distortion isn't too bad either.

If you set up the NTD1 circuit carefully, and match the voltage and the drains of each fet, then you can get away with no caps at all providing the transformer has some tolerance of small DC offsets.

Worst case, all you need is one cap to block DC in the transformer winding across both drains. The value of the cap needs to be sufficient to not cause an LF rolloff with the reflected impedance from the input of the tube amp.

I liked the idea of using a center tapped transformer primary, and putting the cap between the two windings, but it really doesn't matter where it goes.

If I were you, I'd put the transformer in the DAC case rather than in the amp case as your diagram implies, and just use them to add SE outputs to the DAC.

Cheers,
Owen
  Reply With Quote
Old 3rd November 2013, 06:28 PM   #638
Rolle is offline Rolle  Denmark
diyAudio Member
 
Join Date: Sep 2010
Location: Kolding
Hi Owen

Thanks alot for taking the time to answer my question reg. BAL-SE transformer connection I have ordered the transformers from sowter this evening and can't wait to get them connected

good idea to put the transformers in the dac case - will do that

I have attached new picture just to be absolutely sure I have understood you comments correctly. So basically I can short the output coupling cap (C52) and get away with a coupling cap in position C29 to block DC across the transformer windings (4 & 6) to be on the safe side - right?

regarding calculating the capacitor size - I just realise that R20 (100k) is parallel with input impedance of my tube amp 50k - so this gives me R=33k to use in formula for corner freq F = 1/(2 * pi * C * R) right?

Thanks
Attached Images
File Type: jpg sowter3575 connection.JPG (41.5 KB, 271 views)
  Reply With Quote
Old 4th November 2013, 12:30 AM   #639
opc is offline opc  Canada
diyAudio Member
 
opc's Avatar
 
Join Date: Oct 2004
Location: Ottawa, Ontario, Canada
Hi Rolle,

What you have listed is exactly correct, and your diagram is also correct. If I were you I would be very tempted to try and make it work with no coupling caps at all, but the safest method would certainly be to keep just one of them.

Both R20 and R23 are no longer required for your application, so you should remove them. They were intended to keep DC on the output side of the coupling caps to a minimum, but that won't be an issue for you as you have a transformer.

That also means that you only need to size the caps for the reflected input impedance of the tube amp you're driving. If I were you though, I would go for the largest value film cap you can fit/afford, and bypass it with smaller value film caps.

Cheers,
Owen
  Reply With Quote
Old 16th November 2013, 10:25 AM   #640
Rolle is offline Rolle  Denmark
diyAudio Member
 
Join Date: Sep 2010
Location: Kolding
Hi

just want to share my experience

I got the Sowter 3575 transformers and hooked them up the other day. I bought 2 Jantzen superior Z-cap 3,3uF and bypassed them with mundorf silver/oil 0,22uF (I am not really sure I dare going down the cap-less road :-) )

But WOW - what a big difference in sound - now I hear the highend sparkle I was missing and much better seperation of instruments . I get a Fullbodied warm sound but still with good highend detail - instuments sounds correct like when you are at a live concert - nice balance from top to bottom. Female and male voices sounds wonderfull. Music just flows effortless.

Thanks Owen for all your efforts in making this I/V possible and the help an guidance you and others in this thread have given. This is truelly an amazing I/V and for sure my new reference I/V :-)

Have a nice day
Rolle
  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
A New Take on the Classic Pass Labs D1 with an ESS Dac opc Digital Line Level 1760 29th December 2013 02:54 AM
Pass D1V3 DAC - build thread spzzzzkt Pass Labs 224 8th December 2012 03:40 AM
FS: Elektor Audioo DAC-2000 w/Pass labs D1 clone I/V sachi Swap Meet 4 26th November 2010 04:57 PM
IRF610 I/V convertion from Pass Labs D1 dac - single ended schiller Digital Line Level 5 15th October 2009 04:33 PM


New To Site? Need Help?

All times are GMT. The time now is 11:47 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