Parasound & ATI amps

[sharkman]

A little image search.
I really like the ATI. Dang, that is a clean layout
ATI Custom Series

While Parasound is no slouch, it has a little more complicated internals.
http://www.parasound.com/img/halo/a31_inside_silver.jpg

Here is mine, it's not nearly as clean, but it's 6 channels
https://www.google.com/search?q=parasound+1206&client=firefox-a&hs=7rU&rls=org.mozilla:en-US:official&channel=sb&source=lnms&tbm=isch&sa=X&ei=AytAU-y4M7KvsATcvYCwCQ&ved=0CAkQ_AUoAg&biw=1385&bih=778&dpr=0.9#facrc=_&imgdii=_&imgrc=zNVkN9uQoqXQ1M%3A;fxuEvbHrfd02kM;http%3A%2F%2Fwww.minhembio.com%2Fbilder%2Fbild%2F%3Fpic_id%3D55789.jpg;http%3A%2F%2Fwww.minhembio.com%2Fsoftman3%2F26234;850;638

I suspect on the Halo, a good % of the $ is also going to aesthetics, while the ATI has all the $ going to parts and performance. But I doubt you will be disappointed with either.

Crown is a different animal altogether
https://www.google.com/search?q=crown+xls&client=firefox-a&hs=soU&rls=org.mozilla:en-US:official&channel=sb&source=lnms&tbm=isch&sa=X&ei=OypAU8PoLKjmsATO64CIAw&ved=0CAoQ_AUoAw&biw=1385&bih=778&dpr=0.9#facrc=_&imgdii=PCzGyS2_QbKX6M:;Cd7f1FM3toUyuM;PCzGyS2_QbKX6M:&imgrc=PCzGyS2_QbKX6M%3A;cPzm5cJz5eOwiM;http%3A%2F%2Fwww.punkjob.com%2FCrownXLS1500-2.jpg;http%3A%2F%2Fwww.talkbass.com%2Fforum%2Ff15%2Famp-guts-photos-official-thread-lets-see-those-pics-513929%2Findex20.html;1200;600

FYI, the Halo A21 is a significantly different beast than the A31 . Here's a link.(Damn, I start drooling just looking at that beast!)

 

[RichB]

FYI, the Halo A21 is a significantly different beast than the A31 . Here's a link.

I have heard that and auditioned a friends A21 comparing to my A51 last weekend.
Wholly unscientific, we listened to several songs. Among them was the Cowboy Junkies SACD "Crossroads".
This track is an amp heater with a powerful bass line punctuated with an occasional guitar and somewhat sibilant female vocal.
The A21 seemed a bit more controlled and the vocal was a bit more forgiving on the ears. There was no level matching but at this volume it should not be that large a difference since they are spec'ed the same.

The A21 a 1.2 kVA and 100,000 µF power supply filter capacitance (per channel 6ooVa/50,000 + higher class-a operation)
The A51 has a 2.2 kVA transformer and 164,000 µF power supply filter capacitance (per channel 400Va/32,800)

However, all the other specs are the same

- Rich

 

[jinjuku]

There was no level matching but at this volume it should not be that large a difference since they are spec'ed the same.

The A21 a 1.2 kVA and 100,000 µF power supply filter capacitance (per channel 6ooVa/50,000 + higher class-a operation)
The A51 has a 2.2 kVA transformer and 164,000 µF power supply filter capacitance (per channel 400Va/32,800)

However, all the other specs are the same

- Rich

I don't think you realize how uninformed your response sounds. I place that right in line with mere conjecture.

It's like someone that doesn't know how to program in any language, do any database development, call up and want something custom done and then go onto telling me how easy it should be to write.

It's more than a pet peeve to see numbers like this compared across different amplifiers unless we know that they share common class and topology layout.

I've certainly seen it done with A/AB and Class D where of course the #'s are going to look in favor of the A/AB until efficiency is discussed.

 

[PENG]

It's more than a pet peeve to see numbers like this compared across different amplifiers unless we know that they share common class and topology layout.

A21,A31,A51 do share the same topology, likely same amp sections too except the 21 has 2 channels and the 51 has 5 channels. I would say it is highly likely the power supply designs will be very similar except the 31 and 51 need larger transformers and more storage capacitance as they have more channels to feed.

 

[RichB]

I don't think you realize how uninformed your response sounds. I place that right in line with mere conjecture.

It's like someone that doesn't know how to program in any language, do any database development, call up and want something custom done and then go onto telling me how easy it should be to write.

It's more than a pet peeve to see numbers like this compared across different amplifiers unless we know that they share common class and topology layout.

I've certainly seen it done with A/AB and Class D where of course the #'s are going to look in favor of the A/AB until efficiency is discussed.

Actually, I have all of the above skills so I sympathize.

However, the post was referring to the Parasound A21 and the Parasound A51 Class A/B amps. Comparing the specifications of those specific amps seems valid to me.

No reference was made to class-D because these specifications are clearly not applicable.

- Rich

 

[slipperybidness]

Then you would have to put a lot of the Class D amps above that since they don't have any need of a large toroidal transformer. No large Transformer = no possibility of transformer hum



Also check out the Parts Express Tech Talk Forum about the Crown. I still say he should try the Yamaha PS3500S from Amazon and return it if he doesn't like it. Get that, get the Parasound/NAD/ATI what ever. Invite a member from AH to go over and help him be honest about the evaluation (SBT).

Yup, smaller transformers is certainly one of the advantages of class D. I don't hear any transformer hum in any of my systems, even my tube amp with 3 honking transformers. Yeah, if I put my ear right next to it, then maybe a little, but I don't listen to music with my ear on the transformer so it is a non-issue

I still think of all the amps we are discussing, the ATI just has the cleanest, most elegant layout inside. There is something to be said about simple elegance vs. complicated layout.

 

[Irvrobinson]

The A21 seemed a bit more controlled and the vocal was a bit more forgiving on the ears. There was no level matching but at this volume it should not be that large a difference since they are spec'ed the same.

I commend you, Rich, for showing self-restraint through what read like an unwarranted personal attack. OTOH, I do think you deserve a time-out for the "more controlled" and "more forgiving" quips. Try to imagine what distortions might be responsible for differences like this. Nonlinear behavior? Distortion? Unlikely, I think. And no level matching? Make that a double time-out.

 

[jinjuku]

Actually, I have all of the above skills so I sympathize.

However, the post was referring to the Parasound A21 and the Parasound A51 Class A/B amps. Comparing the specifications of those specific amps seems valid to me.

No reference was made to class-D because these specifications are clearly not applicable.

- Rich

But not getting them matched is a problem. Once level matched, assuming a linear response, you can then make a more data driven assessment.

I'll stand by my post.

If it's going to be pointed out that these amps share a lot of commonality then I will point out they are most likely gain staged the same. So in this instance not pink noising them but making a declaration...

Sorry I'm just not going to buy the ad-hoc assessment.

 

[Irvrobinson]

I still think of all the amps we are discussing, the ATI just has the cleanest, most elegant layout inside. There is something to be said about simple elegance vs. complicated layout.

I admit that when I see wires flying around an amp chassis, especially any wires in the signal path, I do wonder about the amp's unweighted SNR. There's also the reliability and quality factors, as those solder joints are usually handmade, and humans assemble these products, so flying wires are susceptible to all sorts of problems. It is a factor worth making a buying decision about? Maybe. Definitely maybe.

 

[jinjuku]

I commend you, Rich, for showing self-restraint through what read like an unwarranted personal attack. OTOH, I do think you deserve a time-out for the "more controlled" and "more forgiving" quips. Try to imagine what distortions might be responsible for differences like this. Nonlinear behavior? Distortion? Unlikely, I think. And no level matching? Make that a double time-out.

Irv, how would you like me to point out the obvious technical problems with his assessment?

I honestly don't think Rich realized the ignorance of it. Now before someone gets all up in arms over the use of the term 'ignorance'. It's not a personal slight, it's not a personal attack. It is what it is and I have certainly and deservedly been on the receiving end.

The cursory person reading this thread needs to know the problems with his approach to evaluation. It's some form of disinformation pure and simple.

Not trying to step on anybody. If anyone here, including me, can't stand to be corrected then I would have to think about participating publicly.

 

[sharkman]

A21,A31,A51 do share the same topology, likely same amp sections too except the 21 has 2 channels and the 51 has 5 channels. I would say it is highly likely the power supply designs will be very similar except the 31 and 51 need larger transformers and more storage capacitance as they have more channels to feed.

I invite you to compare the pictures of the A31 and A21 with their covers off. The A21 has much more circuitry per channel than the A31 does. Incidentally, that is all I'm saying here, the pictures need to be compared. There is someone roaming around here today who needs to take his happy pills, so I'm not going to say anything further in that regard. It's interesting and I'd love to hear Richard Schram or John Curl discuss why the differences exist.

 

[Irvrobinson]

Irv, how would you like me to point out the obvious technical problems with his assessment?

I honestly don't think Rich realized the ignorance of it. Now before someone gets all up in arms over the use of the term 'ignorance'. It's not a personal slight, it's not a personal attack. It is what it is and I have certainly and deservedly been on the receiving end.

The cursory person reading this thread needs to know the problems with his approach to evaluation. It's some form of disinformation pure and simple.

Not trying to step on anybody. If anyone here, including me, can't stand to be corrected then I would have to think about participating publicly.

Assuming you're referring to his listing of the KVA ratings of the transformers and the ratings of the power supply capacitors, Rich was making a comparison, not an assessment, and I do think, frankly, you overcooked your response a bit. I agree that getting too hung up on these random electrical ratings taken out of context is probably a mistake for assessing relative quality, and unless the amp is under a very high degree of stress I can't believe the power supply differences would be readily audible, especially if the active amplification stages were so similar. Class AB audiophile amps do tend to have over-designed power supplies, so that when John Atkinson or Gene measure them into 4 ohm or 2 ohm loads they demonstrate near-perfect "doubling down" power output. And Parasound may just have sized the power supply parameters for the A21 versus the A51 knowing what a 15amp mains circuit could actually feed, or a myriad of other design considerations. And even if they did skimp a bit it would, IMO, be quite a feat to hear the difference. At the end of the day however, I'm still thinking that patience and explanation is a better way to educate than intolerance. (Even if I'm so often imperfect in that regard myself.)

 

[jinjuku]

Assuming you're referring to his listing of the KVA ratings of the transformers and the ratings of the power supply capacitors, Rich was making a comparison, not an assessment, and I do think, frankly, you overcooked your response a bit.

No. I wasn't commenting on the #'s comparison. I was commenting on the subjective assessment of Vocals and Bass reproduction.

I'm also not arguing any actual #'s he posted. Those are all indeed fact. What I want someone just reading this thread to realize is there is an inherent problem just comparing numbers and IMO thought that some context needed to be provided.

 

[jinjuku]

At the end of the day however, I'm still thinking that patience and explanation is a better way to educate than intolerance. (Even if I'm so often imperfect in that regard myself.)

I was annoyed at the post because he mentioned the lack of level matching and then as if that excuses the obvious problem goes ahead with the assessment.

I don't believe it rose to the level of personal attack. Rich knew better IMO.

 

[RichB]

But not getting them matched is a problem. Once level matched, assuming a linear response, you can then make a more data driven assessment.

I'll stand by my post.

If it's going to be pointed out that these amps share a lot of commonality then I will point out they are most likely gain staged the same. So in this instance not pink noising them but making a declaration...

Sorry I'm just not going to buy the ad-hoc assessment.

Fair enough, I am not sure I do either

I have read posts by Parasound owners and representatives stating that the A21 is a very different design but the performance specs are the same. The purpose of my post was to explore what backs up these statements the possibility that if there are differences could they stem from a more robust power supply.

The particular, completely non-scientific observation was made at near reference level to stress the amps. It is likely that these amps were at or near clipping.

- Rich

 

[PENG]

I invite you to compare the pictures of the A31 and A21 with their covers off. The A21 has much more circuitry per channel than the A31 does. Incidentally, that is all I'm saying here, the pictures need to be compared. There is someone roaming around here today who needs to take his happy pills, so I'm not going to say anything further in that regard. It's interesting and I'd love to hear Richard Schram or John Curl discuss why the differences exist.

I understand you point, looking at those pictures the A21 does seem to be more jam packed with more circuit components. I only have an A21 but without removing the top I can see clearly that while it is nearly full on the horizontal plane, there are still lots of space height wise. The A31 has an extra channel so I guess they have to layout the circuit boards in the vertical orientation and it is therefore hard to compare the two just by looking at those pictures. So I am going to assume (I know that's not reliable) that they look different only because the layouts are different, not that the A21 has much more circuitry per channel as such.

I email Richard a few times recently so I don't want to bother him again but I hope you don't mind asking him if in fact the A21 is a different beast and has much more circuitry per channel. I bet he will say no and will confirm that the amp sections are nearly the same, standardization is good for business afterall. That's just my educated (hopefully) guess and I could well be wrong.

 

[sharkman]

I understand you point, looking at those pictures the A21 does seem to be more jam packed with more circuit components. I only have an A21 but without removing the top I can see clearly that while it is nearly full on the horizontal plane, there are still lots of space height wise. The A31 has an extra channel so I guess they have to layout the circuit boards in the vertical orientation and it is therefore hard to compare the two just by looking at those pictures. So I am going to assume (I know that's not reliable) that they look different only because the layouts are different, not that the A21 has much more circuitry per channel as such.

I email Richard a few times recently so I don't want to bother him again but I hope you don't mind asking him if in fact the A21 is a different beast and has much more circuitry per channel. I bet he will say no and will confirm that the amp sections are nearly the same, standardization is good for business afterall. That's just my educated (hopefully) guess and I could well be wrong.

Thanks for your thoughts, perhaps the only extra circuitry has to do with the ground lift and mono block feature of the A21. Although the A31 and A21 both have the same capacitance totals, that wouldn't count for much. Don't know why I look at the 2 pictures and see more in the A21, maybe it's a placebo ownership thing!

 

[PENG]

Thanks for your thoughts, perhaps the only extra circuitry has to do with the ground lift and mono block feature of the A21. Although the A31 and A21 both have the same capacitance totals, that wouldn't count for much. Don't know why I look at the 2 pictures and see more in the A21, maybe it's a placebo ownership thing!

Well, as much as I like to use that P word, I wouldn't think it is Placebo in this case, more likely optical illusion as the amplifier cct boards are mounted vertically. In the A21, they lay flat horizontally so there are tons of empty space above the boards. Just to satisfy your curiosity I may email Parasound again. The A21 does have more kVA per channel and a little more capacitance per channel as well. For under 2K, I think it really is the amp to beat.

 

[ematthews]

I'm a little confused. Jeff at ATI said the amp that I am looking at on classic audio parts would be a brand new A stock item. On the site it says all amps are B stock... What???

 

[jinjuku]

I'm a little confused. Jeff at ATI said the amp that I am looking at on classic audio parts would be a brand new A stock item. On the site it says all amps are B stock... What???

Could be a sales gimmick. But if they are all A stock and getting a good deal... ATI builds theirs like a proverbial tank.