Building the ultimate NOS DAC using TDA1541A - Page 452 - 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 12th October 2012, 07:47 AM   #4511
diyAudio Member
 
Join Date: Apr 2002
Has anyone here built the "charge transfer power supplies" that John suggests early in this thread?
  Reply With Quote
Old 12th October 2012, 10:27 AM   #4512
diyAudio Member
 
maxlorenz's Avatar
 
Join Date: Oct 2003
Location: osorno , Chile
Hi Dr H,

I use the charge-transfer supplies (regular or floating) in all my equipment for years now, even on power amps (with active devices suitable for the task) with very good performance. I have recommended them everywhere but it seems with little success...
In fact, it is hard to listen to non charge-transferred units once one gets used to the clean sound they provide...

Good luck,
M.
  Reply With Quote
Old 12th October 2012, 12:37 PM   #4513
diyAudio Member
 
Join Date: Apr 2002
Hey MaxLorenz,
I'd really like to try them in my amps (CLass A, 400W) and cd player, so if you have advice, please send me a PM.
Thanks
Ryan
  Reply With Quote
Old 12th October 2012, 12:55 PM   #4514
diyAudio Member
 
Join Date: Apr 2003
Location: Eastern Pennsylvania
Quote:
Originally Posted by maxlorenz View Post
Hi Dr H,

I use the charge-transfer supplies (regular or floating) in all my equipment for years now, even on power amps (with active devices suitable for the task) with very good performance. I have recommended them everywhere but it seems with little success...
In fact, it is hard to listen to non charge-transferred units once one gets used to the clean sound they provide...

Good luck,
M.
Hi, Max,

Would you publish the schematic and parts list of the power amp scale implementation of the floating charge-transfer circuit? I often have A.C. line noise at my home, in the form of very audible 'buzzing' sound, so severe that I have been seriously considering powering even my power amp from a high capacity battery supply. Not to hijack John's thread, but I'd also be interested in reading any experience you might have with the subjective quality of charge-transfer power versus battery power. Please feel free to e-mail this information, if you would prefer to.
__________________
Ken
  Reply With Quote
Old 12th October 2012, 08:24 PM   #4515
JOSI1 is offline JOSI1  Germany
diyAudio Member
 
Join Date: Mar 2006
Location: Bad Hersfeld
Hello John,

for the improvement of the TDA1541A-MKxx DAC you changed the power supply concept several times.
I'm a little confused concerning the use of the capacitance multiplier.
What is the advantage of a 4th order capacitance multiplier compared to a capacitance multiplier in plus lead and minus lead.
Does the 4th order capacitance multiplier consist of a chain of 4 RC elements (1st order) connected to the base of one darlington transistor located in the plus lead only?
If not could you please explain the structure.
  Reply With Quote
Old 12th October 2012, 08:56 PM   #4516
diyAudio Member
 
maxlorenz's Avatar
 
Join Date: Oct 2003
Location: osorno , Chile
Hi Dr. H and Ken,

Wow guys, you maybe ask too much from limited skills, but I will try to help. I mean, I can help the circuit to work but I cannot advice the optimal solution for each case. Anyway, I am sure -EC-, which is altruism personified, will jump in any minute.

For CD player just make the same circuit -EC- designed. Almost any mosfet will do, I imagine.
For a high power class A amp the demands of voltage and current will be huge for the mosfet and diodes, and will need to be heatsinked. Perhaps better try with normal diodes and not shottky, at first, because they can take more stress and are cheaper. I will tell you how I did the search: first investigate what are the demands for V and I of the amp; then entered my dealer's site (RS-components) and searched for the mosfet and shottkies that best suited the task (and were not hyperexpensive). You will need to buy high wattage resistances also, but I as said I am unable to tell what values are optimal, like gate input capacitance...etc.

I have never built a high power "floating charge transfer supply" but I am considering as a next project (after DX Blame and SSA ) for a Makura's Power Follower "following" a high output DI M1 dac with variable I/V resistance: only one polarity needed. I only need the transformer. If I don't get it, I will make a regular charge transfer suply.

Buzz is a nightmare. I have been fighting with it on my main system (98 and 105db/W efficient transducers) for years and now I have acceptable low levels. I decided to rewire all the components for proper grounding, which would be my first advice. Only the amps are still pending...I think reading all the stuff about proper grounding (I did it but still have buzz, he, he) should be a requisite to become a member of the Forum that would save a lot of anger and frustration...once we are frustrated we cannot think correctly and chances are that we never solve the problem

A tip that has helped me, if the buzz increases with increasing volume, the problem is "before" the preamp; if it is not modified, the problem is "after" the preamp. If it appears that the noise increases or decreases, depending on the source selected, the problem maybe the preamp itself...

That said, floating charge-transfer supply (for now on FCTS) is dangerous and will need proper double insulation technique.

For a double polarity FCTS you will need doubling -EC's- circuit. He published the circuit years ago. I will try to find it but I remember an 8 lead TX ( or two "center tappered" TXs in parallel) was needed. Again, you will need to look for suitable (V and I) Darlingtons and schottkies. A tip: FCTS doubles output V! so high voltage caps are needed and TX output V must be chosen accordingly.

Example: if you build one FCTS with a 9*2VAC TX (9-0/9-0) each rail will contribute with 9*1.44 minus diode loses so you will end with more or less a 22-0VDC FCTS...am I right EC?

Sorry guys, I am at work now and very busy. Will look for further info tomorrow.

Cheers,
M.

Last edited by maxlorenz; 12th October 2012 at 09:13 PM.
  Reply With Quote
Old 12th October 2012, 09:44 PM   #4517
diyAudio Member
 
Join Date: Apr 2003
Location: Eastern Pennsylvania
Quote:
Originally Posted by maxlorenz View Post
Buzz is a nightmare. I have been fighting with it on my main system (98 and 105db/W efficient transducers) for years and now I have acceptable low levels. I decided to rewire all the components for proper grounding, which would be my first advice....A tip that has helped me, if the buzz increases with increasing volume, the problem is "before" the preamp; if it is not modified, the problem is "after" the preamp. If it appears that the noise increases or decreases, depending on the source selected, the problem maybe the preamp itself...

Cheers,
M.
The buzzing I'm getting is not due to any ground loop problem, as I can disconnect the preamp and the buzz remains unaffected. Also, it's much worse at night than during the daytime. I can see the noise via my Tek digital scope, it is an approx. 2.5kHz sawtooth waveform riding the 60Hz line in periodic bursts. Ugly on the scope, ugly to hear.
__________________
Ken
  Reply With Quote
Old 15th October 2012, 06:36 AM   #4518
diyAudio Member
 
Join Date: Apr 2002
Thanks MAxLorenz, appreciate the feedback.
  Reply With Quote
Old 15th October 2012, 12:14 PM   #4519
diyAudio Member
 
maxlorenz's Avatar
 
Join Date: Oct 2003
Location: osorno , Chile
Sorry to be silent. I got the flu.

Look at this high power shottky:

Schottky Rectifier Common Cathode Diode 90V 20A | eBay

Datasheet says 370pF capacitance.

The other day I re-read the thread and could not find the double polarity FCTS. I will try to figure out a schematic.

Good luck.
M.
  Reply With Quote
Old 15th October 2012, 05:52 PM   #4520
oshifis is offline oshifis  Hungary
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
Quote:
Originally Posted by maxlorenz View Post
The other day I re-read the thread
  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



New To Site? Need Help?

All times are GMT. The time now is 03:40 AM.


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