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

Member
2004-08-19 7:04 pm
NC
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.
 
ohenry said:
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.
 

ohenry

Member
2004-08-19 7:04 pm
NC
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.
 
Re: Check source

Panelhead said:
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?
 
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
 
ohenry said:
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

Member
2004-08-19 7:04 pm
NC
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. :)
 

ohenry

Member
2004-08-19 7:04 pm
NC
It seems that there's some experience here with both the tripath eval board and a stock retail version. How does the eval board stack up against a sonic impact. Is it worth it to get the eval board before going to the trouble of new cabinet, volume, etc.

It depends. If you don't want to or have the skills to do modifications, the eval board TA2024 will sound better that the stock SI due to it's parts (especially the input cap values = better bass). The eval board needs a preamp and a power supply (SLA battery, wall wart, a $20 Pyramid supply from Parts Express, etc.). You'll need a PS for the SI as well. Most folks weren't too happy with the built in AA batteries.

Eval boards facilitate experimentation since they have banana and RCA jacks built in making temporary hook ups easier.

I suppose it all comes to your intentions and the scope of the project.
 

dgo

Member
2005-03-10 1:45 am
@home
Interesting. I've got some thoughts and some questions to add.
I too bought two evaluation boards some time ago at profusion , the 2024 mini and the 2021b.

Comparing the 2024 to the stock t-amp board it sounded better straigth away. Like already said, more bass due to the larger input caps. I also got the feeling they needed less burn-in time and sounded less shriller from the start (possibly they've already got some burn-in time one them already, which makes sense as they are evaluation boards, aimed to sell the tripath chips?)

Same with the 2021b, although I keep missing the defined clarity of the 2024's sound. Like described in another thread about the 2024's 'magic', the two chips absolutely sound different.
Now I'm very curious, (opentop?) what's the difference between the 2020 and the 2024 based board, especially concerning the highs?


About voltage:

I ran both of the same voltage 4A PSU @ 13,8 V. The 2021b max takes 16V max (I'm running that one now). I ran the 2024 mini board with additional heatsink, which caused no problems.

Anyway, unfortunately, the evaluation 2024 mini is dead now, I killed it after 100+ hours with *ahum* wrong polarity. Damn.

The 2024 takes 13,2 max officially but uptil now I was very confident 13,8V was no problem. Until a t-amp 2024 died on me last week (my succesfully input modded t-amp which also had about 100+ hours on it, Boohoo) for no appearant reason. While listening, 1 channel died, I switched off, came back again, then died for good.

Now, (before I consider buy another evo board I'm a little hesitant using the 13,8 V again.
Or should this just be debet to the bad quality t-amp boards?

The overal quality of the evalution boards tempts me to buy again, but it's about the price of three t-amps right now. (while Profusion raised their prices in the mean time !)
 
Well dgo,

Sorry to hear about your T-Amps/2024's gone astray. I had two T-Amps and in the end they also broke down. I now use the 2020 EB's without any problems so far. And about the highs: as far as I can tell, they sound as brilliant as the highs from the T-Amp. And 13,8V will cause no problems. As I recall it, their specs lie somewhere between 12 and 14.2 V.