TDA1541 + I/V Output Transformer - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, 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 6th April 2004, 08:24 AM   #1
mrstone is offline mrstone  Hong Kong
diyAudio Member
 
Join Date: Aug 2003
Location: Hong Kong
Question TDA1541 + I/V Output Transformer

Hi Folks,

In transformer-coupled I/V stage, a resistor (around 20 ohm) will be used to terminate the Idac output and then couple to a step-up transformer.

However, at idle stage (silence, no signal), TDA1541 have sink current at the output.

So, my question is: Will this sink current saturate the step-up transformer? Any transformer in the market can be used and is suitable for this purpose?

Your suggestions and comments will be appreciated! Thanks!!

Cheers
Mr. Stone
__________________
Mr. Stone
  Reply With Quote
Old 12th April 2004, 04:55 PM   #2
mrstone is offline mrstone  Hong Kong
diyAudio Member
 
Join Date: Aug 2003
Location: Hong Kong
Pls help.
__________________
Mr. Stone
  Reply With Quote
Old 12th April 2004, 09:32 PM   #3
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
No problem.......

there are specially wound transformers for this purpose. Like the Sowter 8347 1:18 TX. Goes very well, I have built 3 applications with it with Current outputs and it works just fine....

tc
doede
  Reply With Quote
Old 12th April 2004, 10:13 PM   #4
guido is offline guido  Netherlands
diyAudio Member
 
guido's Avatar
 
Join Date: Mar 2002
Location: diepe zuiden
Use two dac's, feed one with inverted signal. Each has the resistor to gnd. Then connect the transformer between the resistors. No DC over the transformer.

Greetings,
__________________
GuidoB
  Reply With Quote
Old 13th April 2004, 03:23 AM   #5
mrstone is offline mrstone  Hong Kong
diyAudio Member
 
Join Date: Aug 2003
Location: Hong Kong
Hi dddac, guido and all,

Could I use Amplimo Signal transformer type TM3? as it's much cheaper than Sowter...

Actually, I send email to Amplimo and asked for the spec, but up to this moment, I still haven't received any response from them....anybody can share your experience on it?

Thanks so much!!
__________________
Mr. Stone
  Reply With Quote
Old 13th April 2004, 05:12 AM   #6
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
Quote:
Originally posted by guido
Use two dac's, feed one with inverted signal. Each has the resistor to gnd. Then connect the transformer between the resistors. No DC over the transformer.

Greetings,


Good trick Guido, as extra bonus you have extra output voltage. One point: Output impedance increases by 4x ...

with the sowter = 14k. Should be ok for most apps...

tc
doede
  Reply With Quote
Old 13th April 2004, 05:13 AM   #7
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
Quote:
Originally posted by mrstone
Hi dddac, guido and all,

Could I use Amplimo Signal transformer type TM3? as it's much cheaper than Sowter...

Actually, I send email to Amplimo and asked for the spec, but up to this moment, I still haven't received any response from them....anybody can share your experience on it?

Thanks so much!!


I don't know this one.... sorry, just try it I would suggest?
tc
doede
  Reply With Quote
Old 13th April 2004, 10:21 AM   #8
guido is offline guido  Netherlands
diyAudio Member
 
guido's Avatar
 
Join Date: Mar 2002
Location: diepe zuiden
From the website:

Signal transformer type TM3 Euro 26,47

Never try to check the windings with an ordinary multimeter. The DC-current of the meter will magnetise the core!

Ratio
1 : 15

frequencyrange +3dB
30 - 25000 Hz

max. input at 30Hz.
800mV

to connect primary
microphone of max. 200 Ohm

to connect secondary
min. 45 kOhm

primary wires
green - grey

secondary wires
red - blue

lead length
70mm

max.voltage between prim. and sec. winding
100V

dimensions excl. screwthreat
22 x 23mm (diam x height)

Greetings,
__________________
GuidoB
  Reply With Quote
Old 16th April 2004, 08:19 AM   #9
diyAudio Member
 
Join Date: Mar 2004
Location: Surrey, UK.
Mr Stone,
Have you used the Amplimo Signal transformer type TM3 ?

What are your findings ?

Regards
firestorm
  Reply With Quote
Old 16th April 2004, 11:00 AM   #10
rbroer is offline rbroer  Netherlands
diyAudio Member
 
rbroer's Avatar
 
Join Date: Mar 2002
Location: Netherlands
My findings:

The TM3 is physically smaller, and output voltage collapses quite easily.
IME, sweet sound, but bass and dynamics suffered using either stepup transformer, TM3 being worst. YMMV.
Also experienced hum problems that I could only solve by giving up galvanic isolation.

In the end too low output for me when using Riv of 22 ohms for
TDA1541 In this setup, the TM3 had almost no output, much less than one would expect when comparing the 18* and 15* stepup ratios.
My preference clearly goes to the Sowter 8347 1:18 TX
__________________
Rudolf Broertjes
  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
Yet another output stage for TDA1541 mevangel Digital Source 8 25th April 2014 02:04 AM
Improvements to TDA1541 dac output stage? sharpi31 Digital Line Level 15 9th February 2009 07:53 AM
Adding secondary of output transformer into cathodes of output stage ? Eico ST-70 freddymac406 Tubes / Valves 3 21st April 2007 06:15 PM
How many TDA1541(A) in parallel without output baffer? iklari14 Digital Source 0 7th August 2003 11:34 AM
First DAC project ,TDA1541 current output George Kubitsch Digital Source 8 6th December 2002 04:30 PM


New To Site? Need Help?

All times are GMT. The time now is 07:06 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