Parasound & ATI amps

[sharkman]

ematthews, what are you considering for the preamp? And whatever you do, don't use silver wire IC's if you want a warmer result.

 

[PENG]

OK.

Sounds to me that "high bias class A/AB" means that they are biased higher than a normal class AB design. As I said previously, Class AB is biased "just above cutoff", so I'm guessing that they are saying it is biased "well above cutoff", approaching class A or midpoint bias.

They are saying more than that, they actually says the A21 will get you about 8W (IIRC) in class A mode. I believe Pass Labs, Anthem, Bryston, ATI and many other class AB amplifiers do operate in similar fashion, taking advantage of simply using bias control to let their class AB amp operate in class A for the first few watts. I think the differences are just at what output level do they reach the class AB point. I could be wrong but I know at least my 4B SST also operates in class A, probably up to 20 to 25W.

The consumption figures at idle may not be a sure bet or accurate indicator as there are other factors, but it could be reasonable to assume if it gets to anything more than 140 to 150W at idle, it is more likely a high (relatively speaking) bias design. It takes quite a bit of quiescent current to account for that much power when the output is zero (idling).

Parasound didn't say much other than just "high bias". Passlabs did provide more detailed description on their website.

https://passlabs.com/articles/leaving-class-a

 

[slipperybidness]

They are saying more than that, they actually says the A21 will get you about 8W (IIRC) in class A mode. I believe Pass Labs, Anthem, Bryston, ATI and many other class AB amplifiers do operate in similar fashion, taking advantage of simply using bias control to let their class AB amp operate in class A for the first few watts. I think the differences are just at what output level do they reach the class AB point. I could be wrong but I know at least my 4B SST also operates in class A, probably up to 20 to 25W.

The consumption figures at idle may not be a sure bet or accurate indicator as there are other factors, but it could be reasonable to assume if it gets to anything more than 140 to 150W at idle, it is more likely a high (relatively speaking) bias design. It takes quite a bit of quiescent current to account for that much power when the output is zero (idling).

Parasound didn't say much other than just "high bias". Passlabs did provide more detailed description on their website.

https://passlabs.com/articles/leaving-class-a

Yup, I remember reading that my 1206 is biased high too, Parasound likes to do that. It runs pretty hot too. For the most part, I think that's a good way to do it, unless you are worried about power consumption (but I also have a tube amp = heater so no concern to me).

I gotta read up on this A to AB swap stuff, my guess is that it may be marketing speak for simply where the amp is biased and then the output power is stated from that calculation.

Maybe TLS or Gene can set us straight.

 

[PENG]

Yup, I remember reading that my 1206 is biased high too, Parasound likes to do that. It runs pretty hot too. For the most part, I think that's a good way to do it, unless you are worried about power consumption (but I also have a tube amp = heater so no concern to me).

I gotta read up on this A to AB swap stuff, my guess is that it may be marketing speak for simply where the amp is biased and then the output power is stated from that calculation.

Maybe TLS or Gene can set us straight.

I also feel that it is marketing hype to a point. Fact is, they still are push pull based, though considered class A by definition at the lower output range.

 

[PENG]

I also feel that it is marketing hype to a point. Fact is, they still are push pull based, though considered class A by definition at the lower output range.

I feel that way because I think it is something that should be expected and that probably most well design class AB amps do have that feature designed in but not all of them talk about it. It should work well if implemented properly using accurately matched components such as transistors etc. Yes it does consume more power overall but still well below that of a real and full time class A amp.

 

[AcuDefTechGuy]

It runs pretty hot too.

Well, that's not good.

I want an amp that is pretty (McIntosh), is efficient, cool, lightweight (like class D Crown DriveCore), and measures like Mark Levinson & Krell on SNR, crosstalk, THD, etc.

 

[slipperybidness]

Well, that's not good.

I want an amp that is pretty (McIntosh), is efficient, cool, lightweight (like class D Crown DriveCore), and measures like Mark Levinson & Krell on SNR, crosstalk, THD, etc.

Riiiiight.

So your ATIs don't put out a lot of heat?

 

[AcuDefTechGuy]

Riiiiight.

So your ATIs don't put out a lot of heat?

My ATIs actually don't get very hot. They just feel warm. I can place my hand right on the top of the case after 4 hours and it feels warm, but not burning hot. My Denon AVP actually gets hotter than my ATI.

 

[slipperybidness]

My ATIs actually don't get very hot. They just feel warm. I can place my hand right on the top of the case after 4 hours and it feels warm, but not burning hot. My Denon AVP actually gets hotter than my ATI.

OK. Let me clarify. After several hours, if I put my hand right on the case and/or heatsinks, it is hot. It is not so hot that I have to take my hand off, so it is not a problem or a concern. But, it does run hotter than many other amps and hotter than my Pio Elite.

Now my Dynaco tube amp runs HOT, that's the nature of tubes.

Now that I think about it, I have an IR thermometer that I've never used to measure my amps with. I guess I'll try it over the weekend.

 

[RichB]

Riiiiight.

So your ATIs don't put out a lot of heat?

The ATI3005 (130 watts at idle) and Parasound A51 (150 watts at idle) sat/sit below a Marantz AV8801. For TV and low level listening both amps felt only warm to the touch but they have a good thermal design with big heat sinks.

The Parasound wears its heatsinks on the outside, the ATI inside.
Playing bass HEAVY content at near reference both amps heatsinkis measure above 130f (using an Infrared thermometer).

Any amp consuming 130 watts at idle is putting that heat into the room / cabinet.

The Marantz measures above 120 F in the center-back but consumes only 60 watts in my system and that does not change. The ATI and Parasound increased the ambient temperature of the 8801 by about 10F even though both are sitting on open shelves and their is about 7 inches between them.

- Rich

 

[slipperybidness]

A little extra reading.
Load line (electronics) - Wikipedia, the free encyclopedia
Amplifier - Wikipedia, the free encyclopedia

 

[ematthews]

ematthews, what are you considering for the preamp? And whatever you do, don't use silver wire IC's if you want a warmer result.

Not sure yet.
Parasound is on my list. Although a tube pre has my attention since I might be aiming for a warmer tone.
I use all Blue Jeans interconnects. Both RCA and Balanced if needed. Including my speaker cables.

 

[ematthews]

My Emotiva amps never seemed to get hot.. Not a big deal to me so much.
So let me ask this. Parasound A23 around $1000, Parasound A21 around 2400, ATI 2000 series. fully balanced for around 1600. All retail. Seems to me that the ATI would be the best deal... I however would love to get my hands on that A21 Beast.

 

[AcuDefTechGuy]

My Emotiva amps never seemed to get hot.. Not a big deal to me so much.
So let me ask this. Parasound A23 around $1000, Parasound A21 around 2400, ATI 2000 series. fully balanced for around 1600. All retail. Seems to me that the ATI would be the best deal... I however would love to get my hands on that A21 Beast.

Don't forget the ATI AT1802, which is almost as powerful as the AT2002.

 

[sharkman]

Not sure yet.
Parasound is on my list. Although a tube pre has my attention since I might be aiming for a warmer tone.
I use all Blue Jeans interconnects. Both RCA and Balanced if needed. Including my speaker cables.

interesting that you're looking at tubes, you might want to consider a tube amp as well. Or for that matter, a one-in-all solution with an integrated tube amp. Peachtree makes some pretty good stuff. But there are many options out there. I kind of feel for you, it's a big project trying to get the right combination. I'm looking for a pre in the summer myself, but my job is easier, I've already got a Halo A21 and am happy to stay with Parasound. But they wouldn't be an option if you want tubes. If you wait long enough, Emotiva will be releasing tube products later this year.

 

[slipperybidness]

My Emotiva amps never seemed to get hot.. Not a big deal to me so much.
So let me ask this. Parasound A23 around $1000, Parasound A21 around 2400, ATI 2000 series. fully balanced for around 1600. All retail. Seems to me that the ATI would be the best deal... I however would love to get my hands on that A21 Beast.

If it were me and my $, I would go ATI this time around.

I have an older Parasound (non halo and pre classic line) that is a proven performer, so for me it would also be trying a new brand (ATI) vs. a brand I am familiar with and like.

I wasn't too big on the ATI either until a AH member posted a pick of the internals. That build quality looks dang good! I also like the other features that ADTG mentioned with the auto-breakers rather than fuses. On a side note, I was just perusing the ATI Classic Audio sight and I will probably be buying some of those huge caps from them to build a bad-a$$ power supply.

To be fair, the Halo internals also look top notch (my older Parasound is also good, almost on par with Halo)! IMHO, the only real advantage that the Halo line has over the competition is the epoxy-encased transformer. I highly suspect that they may be onto something with that! I am of the opinion that pretty much all transformers hum or will hum as they age (mechanical hum), so I bet the epoxy mitigates that quite well.

If you are seriously considering tubes and have any DIY ability, these would probably be a good option:
http://www.tubes4hifi.com/bob.htm#M125
Buuuuuuut, if your Marantz PM8004 is running out of gas, then I would say you need SS power and tubes aint gonna do it for you.

Dunno how you feel about class D, but a lot of guys on here like the Crowns. I'm certain I will have to pick one up one day to see how it performs for me. They are pretty much ubiquitous in the night clubs though, so you know they can handle all types of abuse and put out some serious power. QSC is another brand that is right there with crown.
http://www.parts-express.com/crown-xls-2000-drivecore-series-power-amplifier--245-504

 

[slipperybidness]

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

 

[jinjuku]

To be fair, the Halo internals also look top notch (my older Parasound is also good, almost on par with Halo)! IMHO, the only real advantage that the Halo line has over the competition is the epoxy-encased transformer.

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

Dunno how you feel about class D, but a lot of guys on here like the Crowns. I'm certain I will have to pick one up one day to see how it performs for me. They are pretty much ubiquitous in the night clubs though, so you know they can handle all types of abuse and put out some serious power. QSC is another brand that is right there with crown.
Crown XLS 2000 DriveCore Series Power Amplifier | 245-504

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).

I could certainly tell you when my Parasound was running out of gas as my Crown still had another 3dB of head room. I could also tell you SBT which was which.

Here is the internals of the Yamaha:

 

[jinjuku]

My Emotiva amps never seemed to get hot.. Not a big deal to me so much.
So let me ask this. Parasound A23 around $1000, Parasound A21 around 2400, ATI 2000 series. fully balanced for around 1600. All retail. Seems to me that the ATI would be the best deal... I however would love to get my hands on that A21 Beast.

For $1600 you could take some of the alternatives, spend less, and mono-block them.

 

[RichB]

To be fair, the Halo internals also look top notch (my older Parasound is also good, almost on par with Halo)! IMHO, the only real advantage that the Halo line has over the competition is the epoxy-encased transformer. I highly suspect that they may be onto something with that! I am of the opinion that pretty much all transformers hum or will hum as they age (mechanical hum), so I bet the epoxy mitigates that quite well.

+1 for Epoxy. +10 for aesthetics

The ATI3005 transformer hum could be heard from 12 feet away in my installation. The amp was on the bottom shelf with wood floor in front and a wall about 2 feet in back which I am certain is worse than a carpeted room. The A51 epoxy encased transformer is silent with my ear against it.

To be fair, other with ATI amp owners do not have or are not bothered by this problem. I suppose larger more powerful transformer are more prone to hum.

There seem to be some deals out there so Parasound is price competitive.

- Rich