RMAA and T-amp: anyone?

[antomas]

Hi everybody!
Did anyone used RMAA to measure the perfomances of a SI T-amp (having separate grounds for left and right speaker)?

Thanks for your help,
Massimo

 

[antomas]

Found???

Apparently, enough info to answer my question can be found in this RMAA forum thread:

http://forum.rightmark.org/topic.cgi?id=4:592

Ciao!!!
Massimo

 

[mAJORD]

ive used it to measure a TA2024 T-amp but not an si..

 

[antomas]

Hi mAJORD, thanks for your answer!

ive used it to measure a TA2024 T-amp but not an si..

That's fine for me. Would you please confirm me that you measured one channel at a time? Any other recommendation or tip?
Thanks a lot in the anticipation and have a nice evening (is it evening in Australia?)
Massimo

 

[mAJORD]

no mate sorry, single ended, and measured symultaneously. I didnt realise the Si amps were diff outputs on each channel?

 

[antomas]

Hi mAJORD,
sorry for being so incredibly late in answering. We (me an my wife) had some health problems; nevertheless, I made some homework on this subject...

First of all, Tripath confirmed me that ANY TA2024 amplifier needs two differential buffers (one per channel) to be connected to a single-ended soundcard.

The kind guys of the RMAA forum told me that (but I'm sure you read that) a professional soundcard with a balanced input would allow measuring a TA2024 amp without differential buffer.

In the meanwhile I got in love with the idea that a balanced (H-shaped) attenuator with quite high input and output impedance could allow joining the L and R "cold" terminals together... maybe not

I guess many people (me included) would be happy to read about your setup. Which soundcard? Which attenuator?

Thanks for your answer and sorry for the delay.
Massimo

 

[mAJORD]

HI, hope you're both well now

No I didnt use a differential output.. mine is an AMP1 , using the TA2024, which has single ended outputs. hence not required.

im not sure how you'l get around that problem for your 2022. without making a low noise low distortion buffer to interface it.


-ed forgot to mention, card was at the time a crappy soundblaster Live, but now an E-MU 404.

I am using a voltage divider to attentuate the output over a range of gain. but that is all

 

[antomas]

Now I understand...

...why I got puzzled. It's just a matter of numbers.

You tested an AMP1 using a TA2022 that is single ended, so "joining grounds" is perfectly ok, while my T-Amp uses a balanced TA2024.

I should have built a AMP-1
Maybe in the future
Massimo