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
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
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
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
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,
Greetings,
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!!
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!!
guido said:
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
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,
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,
Mr Stone,
Have you used the Amplimo Signal transformer type TM3 ?
What are your findings ?
Regards
firestorm
Have you used the Amplimo Signal transformer type TM3 ?
What are your findings ?
Regards
firestorm
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
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
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