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-   -   Eb-ta2020 (http://www.diyaudio.com/forums/class-d/56518-eb-ta2020.html)

opentop 2nd May 2005 12:03 PM

Eb-ta2020
 
Well,

I just received the two TA2020 evaluation boards I ordered. And I can say I am not disappointed when I compare them with my earlier purchased T-Amp. But still they sound a bit bass-shy to me.

Now I am using 4 Ohm speakers (Magnepan 0.5). Could that be the reason? In another topic about the TA2024 I read that the input caps for 4 Ohm speakers should be 4.7uF in stead of the 2.2uF the board normally is equipped with.

So: should this do the trick?
And: what about 47uF (what's the difference with 4.7uF?)

ohenry 2nd May 2005 12:48 PM

I had that evaluation board a while back and don't recall it being bass defficient on my 8 ohm speakers. Also, I used a regulated 13.8 volt supply.

Here's my predictable statement: you may want to play it for 100 hours and then assess it's qualities, they do change.;) Changing input and PS caps may be the next thing to do.

I've never heard of a 47uF cap being applied to a signal. I'm sure others here can give advice.

opentop 2nd May 2005 01:00 PM

Quote:

Originally posted by ohenry
I had that evaluation board a while back and don't recall it being bass defficient on my 8 ohm speakers. Also, I used a regulated 13.8 volt supply.

Here's my predictable statement: you may want to play it for 100 hours and then assess it's qualities, they do change.;) Changing input and PS caps may be the next thing to do.

I've never heard of a 47uF cap being applied to a signal. I'm sure others here can give advice.

I also use a regulated 13.8V. But what I am really curious about is: what influence do speakers have on input caps, that is 4 Ohm in comparison to 8 Ohm?

And the 47uF? I am almost I have read about it. Maybe the poster himself was mistaking or 'mistyping'. Or was I 'misreading'?

And yeah, I will play it for another 100 hours. But I though that especially the mids and the highs would benefit from it.

Panelhead 2nd May 2005 01:32 PM

Check source
 
The 2020 board is new to me. Most of the Tripath circuits have a fairly low input impedance. The source used to drive the EB-2020 may not be up to it. If capacitor coupled, the coupling caps need to be 5 - 10 ufd to get minimal rolloff and phase shift.

George

ohenry 2nd May 2005 01:45 PM

I did observe that the mids and highs benefitted most from burn-in as you stated. But sometimes, if the highs are a bit edgy and shrill, they make the amp seem lacking in bass. It's simply a matter of the high frequency presentation being dominant due to that "out of the box" hash, not the bass being weak.

opentop 2nd May 2005 01:50 PM

Re: Check source
 
Quote:

Originally posted by Panelhead
The 2020 board is new to me. Most of the Tripath circuits have a fairly low input impedance. The source used to drive the EB-2020 may not be up to it. If capacitor coupled, the coupling caps need to be 5 - 10 ufd to get minimal rolloff and phase shift.

George


Well, I don't think that is the problem. I use a TEAC vrds-10 cd-player and a Duson C1000 preamplifier.
But what do you mean by your last remark. Should 2.2uF be enough for the input caps (with 4 Ohm speakers). Or should 4.7uF be better?

Panelhead 2nd May 2005 02:35 PM

Coupling caps in preamp
 
I do not know the Duson preamp. If capacitor coupled the bass will be more even if the size of the coupling caps in the preamp are 5 -10 ufd.
This is independent of the coupling cap in the EB-2020. That is used to block dc that is applied to the Tripath chip.
Most tube preamps are not designed to drive the load of the Tripath amps. The input impedance is 10K or less. Most tube preamps are happier with 50 - 100K.

George

opentop 2nd May 2005 04:53 PM

The Duson C1000 preamp is not a tube preamp. Duson took over the once so famous (well, in Europe...) Audio Analyse from France.

opentop 4th May 2005 07:22 AM

Quote:

Originally posted by ohenry
I did observe that the mids and highs benefitted most from burn-in as you stated. But sometimes, if the highs are a bit edgy and shrill, they make the amp seem lacking in bass. It's simply a matter of the high frequency presentation being dominant due to that "out of the box" hash, not the bass being weak.

I think you may be right on that one: after some 50 odd hours of playing, the amp sounds much better now. No more weakness in the bass, silky highs.

ohenry 4th May 2005 04:26 PM

I'm glad it worked out. The TA2020 was the first eval board I received and I didn't realize the sound would dramatically change after burn-in. I hooked it up, listened and promptly gave up on it. It stayed in the closet for a year. Then after reading about others' experiences with burn-in, I gave it another shot. And now I'm hooked on these little T-amps. :)


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