SI beats my AMP1-B's

[soongsc]

Since he thought you were using 6 modules, he mentioned reversing the phase (reverse the connections of the input signal and also the output signal so that all the signals effectively remain in phase) of three of them so that you could effectively reduce possible power supply pumping issues. You could do this with one channel of each amp. In fact I remember reading that Tripath even suggested this if you have supply pumping issues. I'll go look through the application notes to see if I can find that for ya.

Ah, found it! Application Note 9 explains it quite well and even has a connections diagram.

http://www.tripath.com/downloads/an9.pdf

Good idea! I wonder how many traditional amps do this.

 

[soongsc]

AMP1B is a very open sounding amp at low to medium levels.
The UCD's just have more authority in the fact that they stay clean till a very high sound level(for me that is).
The AMP1B is very good value and to be honest I think the UCD180's have more than enough power to listen to. The 400's go a notch higher but for me this is not a necessity. But I prefer the AMP1B over f.i. my NAD C162/C272 combo(am going to sell it).
And just for fun, the NAD uses some 100W at low volume while the AMP1B uses something like 8W with a passive preamp.
But because of these huge housings you forget what they consume/use/burn up.

I looked at AMP 1, it seems to be only 50W, and the UCD is at least 180W. So it seems the UCD should be less limited at higher levels, wouldn't it?

 

[theAnonymous1]

theAnonymous1 - What speakers are you using in your array? What are the tweets?

The drivers are abouts as cheap as you can get, I didn't want to spend loads of money on my first array project. Both drivers came from partsexpress. Here's a link for the tweeter and mids . They actually sound pretty good together, and I plan on pairing them up with 4 $25 12" woofers from MCM in some Ripole cabs.

For starters, you have the 8ohm and 4ohm cases switched

Oops, your right .

Unless your supply voltage was seriously dropping for whatever reason I don't see how you could only measure 14.8Vrms at clipping with 28V rails.

Oh, the measurements were from just before any adudible distortion or clipping, if i let the amp clip it would definitely go up to 19-20v but it sounded nasty.

Can those switching supplies in series handle up to 5A of current draw?

Those supplies are rated at 12A continuous . There is less than 1v drop in voltage at full load and that is from the 0.1R I have in series with the rails.

I replaced some components and the amp is sounding much better now, still have the hiss problem but I've decided I can live with it. With the arrays hooked up the only time I can hear it from my listening position is if there is complete utter silence in the house, and I have to concentrate really hard.

Thanks for that app note, its basically saying to just bridge the amp but not use it as a bridged amp, just reverse one of the speakers polarity to make it in-phase. It also says big supply caps help, is 4 x 33000 enough .

 

[Bgt]

I looked at AMP 1, it seems to be only 50W, and the UCD is at least 180W. So it seems the UCD should be less limited at higher levels, wouldn't it?

The AMP1-B measures 58W/channel and the UCD180 87W/channel both on 8 ohms and 2 channels driven.

 

[exipnos]

theAnonymous1 - Thanks for the info. I already have purchased a large amount of NSB for a HT line array project and I'm looking to find a good tweeter solution. I have some additional question in regards to your solution and the ctc spacing, but I don't want to polute this thread further with speaker talk. Could you start a thread in the loudspeaker forum to discuss your line array? If not maybe you could PM me with email info?

Cheers,

Exipnos

 

[soongsc]

The AMP1-B measures 58W/channel and the UCD180 87W/channel both on 8 ohms and 2 channels driven.

The AMP1 web site says 60W/Channel into 8 Ohms but the UCD180 manual says 105W/Channel into 8 Ohms. I guess it would also depend on what PSU capability you give it. Still seem quite different capabilities when playing real loud. I wonder if both were played such that 40W were delivered, whether sound differences would be significant.

 

[Bgt]

I wonder if both were played such that 40W were delivered, whether sound differences would be significant.

Not really much, the 1B is a bit more bright and that can sometimes be a bit too much but most of the times it is OK. It maybe masks the sound stage it puts down in comparison with the UCD180. UCD amps have more depth.
And the difference between 87W and 105 Watts is not hearable.

 

[innsanes]

how would the SI t-amp compare to a jbl 12 watt stereo amplifer sold at apexjr.com i need something cheap to power my monitor speakers but still get the job done well.

 

[Bgt]

the AMP1B is very cheap to make.

 

[kec]

how would the SI t-amp compare to a jbl 12 watt stereo amplifer sold at apexjr.com

No comparison. That JBL amp is very noisy and pretty much c**p - bought one several years ago so I know. The SI wins hands down. Take the $10 for the JBL and put it towards an SI - or the AMP3 if you have the skills.


-Ken

 

[sx881663]

how would the SI t-amp compare to a jbl 12 watt stereo amplifer sold at apexjr.com i need something cheap to power my monitor speakers but still get the job done well.

http://www.41hz.com/
Amp1 $54
Amp1-b $63
Amp3 $25
All these are kits with loose components so will take some time and skill to complete.
There is the additional expense of a case, connectors, and the power supply. Amp1 requires a substantially more expensive and complex power supply than amp3 or the SI. The amp 3 or SI can be powered by cheap surplus 12v SMPS with minimal additional parts required.
The main difference is in power. For near field monitoring I have used both a highly tweaked SI and a modestly tweaked amp3. I find the amp3 to sound significantly better and this has been reported by many others as well. Tweaking the SI will take about the same amount of time as building the amp3 with a good chance it won’t work when you are done (very tiny parts and a fragile circuit board). The little JBL amp with the a/b chip and electrolytic coupling on the output couldn’t hold a candle to either of the other amps sonically. I think the amp1 would be overkill in this case unless you are using complex multi way monitors. If you are the amp1 would be a better choice as the little amps don’t like complex loads. Of course it will cost 3 times as much to complete. Hope all this will help you make a better decision.
Roger

 

[Bgt]

http://www.41hz.com/
Amp1 $54
Amp1-b $63
Amp3 $25
All these are kits with loose components so will take some time and skill to complete.
There is the additional expense of a case, connectors, and the power supply. Amp1 requires a substantially more expensive and complex power supply than amp3 or the SI. The amp 3 or SI can be powered by cheap surplus 12v SMPS with minimal additional parts required.
The main difference is in power. For near field monitoring I have used both a highly tweaked SI and a modestly tweaked amp3. I find the amp3 to sound significantly better and this has been reported by many others as well. Tweaking the SI will take about the same amount of time as building the amp3 with a good chance it won’t work when you are done (very tiny parts and a fragile circuit board). The little JBL amp with the a/b chip and electrolytic coupling on the output couldn’t hold a candle to either of the other amps sonically. I think the amp1 would be overkill in this case unless you are using complex multi way monitors. If you are the amp1 would be a better choice as the little amps don’t like complex loads. Of course it will cost 3 times as much to complete. Hope all this will help you make a better decision.
Roger

Roger, you're so right. The AMP1B is awsome if modded rightly.
It beats my High End Rotel combo completely.