RMAA and T-amp: anyone?

antomas · 3rd September 2005, 10:44 AM

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 · 5th September 2005, 06:05 PM

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 · 8th September 2005, 12:31 PM

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

antomas · 8th September 2005, 01:13 PM

Hi mAJORD, thanks for your answer!

Quote:

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 · 9th September 2005, 09:30 AM

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

antomas · 16th September 2005, 01:17 PM

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 · 16th September 2005, 01:45 PM

HI, hope you're both well now :P

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 · 16th September 2005, 02:55 PM

...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

3rd September 2005, 10:44 AM	#1
antomas Maître sans marteau diyAudio Member Join Date: Feb 2003 Location: Torino, Italy	RMAA and T-amp: anyone? 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

5th September 2005, 06:05 PM	#2
antomas Maître sans marteau diyAudio Member Join Date: Feb 2003 Location: Torino, Italy	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

16th September 2005, 02:55 PM	#8
antomas Maître sans marteau diyAudio Member Join Date: Feb 2003 Location: Torino, Italy	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

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8th September 2005, 12:31 PM	#3
mAJORD diyAudio Member Join Date: Apr 2004 Location: Brisbane Australia	ive used it to measure a TA2024 T-amp but not an si..

9th September 2005, 09:30 AM	#5
mAJORD diyAudio Member Join Date: Apr 2004 Location: Brisbane Australia	no mate sorry, single ended, and measured symultaneously. I didnt realise the Si amps were diff outputs on each channel?

16th September 2005, 01:17 PM	#6
antomas Maître sans marteau diyAudio Member Join Date: Feb 2003 Location: Torino, Italy	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

16th September 2005, 01:45 PM	#7
mAJORD diyAudio Member Join Date: Apr 2004 Location: Brisbane Australia	HI, hope you're both well now :P 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

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