[wushuliu]

Thank you, Jtwrace.  But as I mentioned, I read the original poster's comments.  I also read Pardales's post where he said he preferred the Miniwatt, and mjosef's post where he said he preferred the Exposure 2010S (a class AB solid state amp).  The other comparisons, as I recall, were to mass-market receivers.  Thus, I'd like to hear more, particularly comparisons to decent audiophile amps rather than mass-market stuff. My head may be spinning, but I'm still thinking clearly. 

Thank you again for your reply, and I'm grateful for all of your work on the case--I may be getting one for this amp if I hear some more specifics.

Proper comparisons to specific retail 'audiophile' amps are going to be hard produce. For one, specs would have to be comparable. The Miniwatt for instance has 3W vs. 250W for the CDA-254, so someone with a setup that can use the MiniWatt isn't likely to consider/need a classdaudio amp. And of course some people are going to prefer something else, we all have different tastes and setups. What IS important is that a large body of people familiar with good gear recognize the value of these $200 - $400 amp kits. The 2010S for instance retailed at 5x the CDA-254.

[Adamay]

Thank you, Wushuliu: when you say that lots of people who are familiar with good equipment are impressed with the Classd amps, that is exactly the sort of information I am looking for. I had the impression (perhaps mistaken) that most buyers of this amp were replacing mass-market receivers with the Classd amp.  I'd be grateful if you (and other users) could provide some specifics--what other amps are you and other users familiar with? I'm only asking for simple comparisons.   (And I would point out that while the Exposure initially sold for 5x the cost of the first generation Classd amp, it can be bought on the used market for only a hundred or so above the cost of the current generation Classd amp + associated case & parts.)

[mjosef]

I just bought one of these amps with the "enhanced" power supply( thanks to Wushuliu)...it might be a couple weeks before I put it together...hopefully mybuild would be better than the loaner I had, I will be using superior connectors, better layout  and better ps filtration...I will be able to offer more long term impressions in comparison to my current amps, tube and SS.

[roymail]

Adamay, I recall reading posts in this thread comparing the Class D Audio amps to Wyred4Sound, CherryJr, Clayton, VTL, some others I can't think of right now.

I'd say that's pretty good company.  Not saying it's better or worse, but the Cherry Jr and Clayton were preferred.  You can draw you're own conclusions.

In view of that, most guys around here figure the Class D amps are a steal.  Reading the thread would be a good investment of your time.   

[FredT300B]

Looking for suggestion on which model/configuration to get. Currently have a Gallo 3.1 and also planning on acquiring the Magnepan 1.7... 

Here's some information that might help. I asked about the SDS-258's ability to drive a four ohm load, and here's the response I received:

"The SDS-258 can run most 4 ohm speakers with no problems at all, but a few people have had trouble a few times with electrostatic types that drop to below 1 ohm. Most 4 ohm speakers do not drop this low and pose no problems for this amp. The power does not double into 4 ohms though due to current limiting and protection circuitry. The SDS-254 is better suited to speaker systems that prove a hard load to drive".

On the basis of this information I ordered the SDS-254 kit to drive my 2.5-way speakers that dip below four ohms. The rationale for this decision is 1) The SDS series are their best product, 2) The SDS-254 offers more versatility for driving a wide range of speakers, and 3) I save a few dollars by ordering the 254 instead of the 258.

[jtwrace]

Here's some information that might help. I asked about the SDS-258's ability to drive a four ohm load, and here's the response I received:

"The SDS-258 can run most 4 ohm speakers with no problems at all, but a few people have had trouble a few times with electrostatic types that drop to below 1 ohm. Most 4 ohm speakers do not drop this low and pose no problems for this amp. The power does not double into 4 ohms though due to current limiting and protection circuitry. The SDS-254 is better suited to speaker systems that prove a hard load to drive".

On the basis of this information I ordered the SDS-254 kit to drive my 2.5-way speakers that dip below four ohms. The rationale for this decision is 1) The SDS series are their best product, 2) The SDS-254 offers more versatility for driving a wide range of speakers, and 3) I save a few dollars by ordering the 254 instead of the 258.

You'll be very happy with your choice.   

[Adamay]

Thanks, everybody!  Mjosef, I'd be very grateful to hear your impressions and comparisons when you have your new unit up and running. 

[celo]

Hello all,

First of all thank you Steve K and others for this thread.

Get ready for a long post

Why are ClassD Audio modules cheaper than IcePower and Hypex although they are made in USA by Team America, not China? IcePower and Hypex are made in Europe where labor costs more, maybe that's why? Or do they simply use better parts and material? Yes, IcePower has B&O behind them which has a big name (not necessarily in an audiophile way) and Hypex has the genius engineer behind them with his UCD invention, so they can charge as much as IcePower. Is this why?

I have read about ClassD audio when I decided to search for a Class D amps since they run cool, relatively cheap and put a lot of power. As most of us, I would like to get the best product for the money. I have looked for used Cary Audio CAI-1, Bel Canto S300iu and they are about $800-$1000 used. However, I feel like they do not have the power I look for. My speakers are Sonus Faber Extrema which is 88db @4 ohms and they are known to demand a lot of good power. I have never had a chance to use them with high powered amps, so I cannot tell this is true. My only Class D experience was with Panasonic XA-45 (I think) but the power was not enough for the speakers and I really could not enjoy/fairly test it.

The other day I came across Seymour AV 5001 monoblocks on Ebay which uses IcePower 500ASP modules. Unfortunately, the seller had them on two different auctions so I could not risk winning one and losing the other auction. I need a stereo amp. Each sold for $260 (MSRP $1100)! That was CHEAP considering Chris Seymour uses good parts on those amps and the 500ASP modules probably sell for $400 each (1000ASP sells for about $600 I think). I was kind of bummed out that I missed these but when I read this thread, I saw that maybe IcePower is not what I am looking for. Maybe I need the Class D audio because I like the tube amp sound. Steve K says that he does not like the Bel Canto which uses IcePower (though that model does not use the ASP version, I think) vs. Class D. (I wish Tom picked a different name)

I also talked to Tom who seems like a nice guy. He replied all my questions very quickly and I am leaning towards his modules the most at the moment. However, I still have questions in mind. According to him which I trust his opinions, there is no mods necessary for his amps which he recommended the SDS-258 for me. However, I have read some of you replace the caps with Panasonic, maybe a different PSU or SMPS, bigger transformer, etc. and get better results. I wonder what kind of mods really worth to perform.

I am NOT a DIYer but looks like with Tom's modules it is pretty much plug-and-play. I know if I want to do some mods, I need to have someone do it for me but I would not mind doing them if they would add better sonics to the amps. I know that SDS-258 is not doubling @4 ohms but it goes above 300wpc. However, the SDS-254, is 250wpc @4 ohms. I am not sure sonically which one would be a better choice. Stereophile's review/measurement of my speakers mentions this:

The impedance rating is a smooth 5 ohms with 4 ohm minima of low reactive content. Tube amplifiers rated over 150W, 8 ohms are advised, set to their 4 ohm taps if available. Solid-state models of good peak-current capacity (10A or more) will drive the Extrema well, given 8 ohm ratings of 75W or more. The 225W clip power of the KSA-150 caused no audible distress with high-quality program. The impedance curve (fig.C) shows that the Extrema's impedance holds within 4 and 9 ohms from 10Hz-2.5kHz before rising gently in the high frequencies.
http://www.stereophile.com/standloudspeakers/915/index6.html

The most important point for me is this though; there are some comparisons with some serious amps, VTL, Bel Canto. So, this tells me Class D maybe the choice but there are also other people who swear Hypex is the best one. I wonder if anybody could add to more amps to the list for comparison. I would love to hear a comparison with Hypex. Yes, Class D is the cheapest among them and I am after a good deal but if I choose to buy Hypex, I would probably pay $150-$200 more which is not too much more than Class D. If Hypex sounds better than Class D, it is worth the extra cost for me.

I am getting close to pull the trigger but do not know which exit should I take....

Thanks for reading

[steve k]

Hi celo,
All I can say is I've always been attracted to amplifiers that create some excitement and emotion in the music. The VTL's had that magic in my system: great dynamics, great bass, warm enveloping mids, and snappy, extended highs that transmitted transients quickly and got the attack of acoustic instruments right. This is what floats my boat. Some would say this is colored, distorted, less true to the real thing and I respect that opinion.

With that said, of all the Class D amps I've heard, they tended to sound cooler, more detached, less emotional but accurate and detailed, that is until I heard Tom's amps. He gets the noise floor way down which brings out inner detail, gets the dynamics, bass and treble right, but the mids have the wonderful warmth of a good tube amp. THey get the wood sound out of a stand up bass or cello ,or acoustic guitar much more like a tube amp but in a cleaner, less noisy presentation of a tube amp. Most of the music I listen to is made by the human voice or acoustic instruments so the color and timbral presentation of instruments is very important to me. Call this colored or warm. I'll take it.

steve

[celo]

Hi Steve,
Thanks for the reply. I have heard many solid state amps. I heard some tube amps. The best amp among the ones I heard which I also owned many years, was the Pass Labs Aleph 3. I did not care too much of the bass being weak which was a negative point for some people. I think you are kinda describing the Aleph 3 when you talk about Tom's modules/amps plus with better bass handling. Obviously, Aleph 3 can cook an omelette when increasing my electric bill, heating the house and still cannot keep up with my Extremas

[roymail]

I am NOT a DIYer but looks like with Tom's modules it is pretty much plug-and-play.  But, it's not difficult to assemble, and you'll get plenty of help here.

However, the SDS-254, is 250wpc @4 ohms. I am not sure sonically which one would be a better choice.

As discussed previously, the Class D amp is in kit form and NOT plug & play.  However, it's not difficult to assemble, and there's plenty of help available here.

The SDS-254 is a very popular choice and one I wouldn't hesitate to recommend.

Steve K knows what he's talking about from both his experience in the hobby and his personal use of Class D amps.

Once again, the Class D amp is an incredible buy, and the SDS-254 would be a good choice.

[celo]

As discussed previously, the Class D amp is in kit form and NOT plug & play. 

The SDS-254 is a very popular choice and one I wouldn't hesitate to recommend.

Once again, the Class D amp is an incredible buy, and the SDS-254 would be a good choice.

I might have exaggerated a little I meant relatively easier than other available kits on the market. It is funny, Tom actually said SDS-258 first. Then after I sent my speakers info, he said SDS-254 but he said he meant the 258. Maybe he has his heart set on the 254.

Do you recommend the 254 because it sounds better than the 258 or you mean it would be enough for my speakers? Thanks Roy!

[jtwrace]

I might have exaggerated a little I meant relatively easier than other available kits on the market. It is funny, Tom actually said SDS-258 first. Then after I sent my speakers info, he said SDS-254 but he said he meant the 258. Maybe he has his heart set on the 254.

Do you recommend the 254 because it sounds better than the 258 or you mean it would be enough for my speakers? Thanks Roy!

It's really not that difficult at all.  We won't let you fail.   

[celo]

Thank you jtwrace, I have no doubt!  Actually, it will be a looooong time till I build them. We are moving overseas in few months and we don't even have a house when we go back I will definitely ask your help. Let me decide which module I should buy first

I need a preamp too. Of course a cheap(er) one. Tom thinks an active preamp is a better choice. I asked him about passive amps.

[roymail]

Many around here are partial to the Pass B1 buffer/preamp. 

Wushuliu has a great thread that walks you through the relatively simple build process.

Enjoy the Music has a nice write up on the B1 buffer.
http://www.enjoythemusic.com/magazine/equipment/0708/first_watt_b1_preamplifier.htm

You can assemble one for about $150.  The B1 buffer and Class D audio amp are a great match especially for those like me who have champagne taste on a beer budget. 

[celo]

Would I look stupid if I asked what is buffer? I have been seeing people talk about it but I am not sure if I know exactly what it does as opposed to preamp. Basically, it does the same thing as the preamp but in a different way?

I also asked Tom about the choice of a module. What do you think???

-----------------------------------------------------------------
Would I be better off buying two SDS-254 modules and bridge them for 500X1 @8 ohms or buying one SDS-258 would be a better choice?
 
I think 254 can do lower impedance better than 258, correct? Going with the 258 would give me only 50wpc more power vs. 254 @4 ohms, correct?

He responded:

Yes, the SDS-254 X 2 bridged is a great choice. This would be allot more power then you’ll ever need.
 
Tom

[walkern]

I've got a Pass B1 buffer and just finished an SDS 254 amp, and I can vouch for the excellence of the combo. I used a Promitheus TVC (transformer based passive volume control) before switching to the B1, and although it was very transparent, and inserted no noise or hum into my system, it was not quite as musically involving as the B1 is.

Here is my take on a buffer:  it is like a preamp, except it has no gain...  so it provides a simple, easy load for your source components to drive (easier than most volume controls), and allows you to control the volume and switch from one source component to another (CD player, media player, DVD player, etc).  Most amps can be driven to full power with 2 volts or less (the typical output of most source components) so a buffer (with no gain) offers the most simple and direct way to manage volume and source selection.  Nelson Pass seems to heavily favor simple circuits and elegant solutions... and the B1 is just that.

The B1 requires some soldering skills, and requires you to be able to identify caps and resistors and such, but on the whole it is a fairly easy kit to build (although the Class D amps are even simpler).  Hope this helps.  Gary Dodd is also offering a battery powered tube buffer as a kit, just in case you'd prefer to add some tube magic ahead of your amp.  There is also a thread about his goodies in the Lab area.

Neil W.

[jtwrace]

Would I look stupid if I asked what is buffer? I have been seeing people talk about it but I am not sure if I know exactly what it does as opposed to preamp. Basically, it does the same thing as the preamp but in a different way?

I also asked Tom about the choice of a module. What do you think???

-----------------------------------------------------------------
Would I be better off buying two SDS-254 modules and bridge them for 500X1 @8 ohms or buying one SDS-258 would be a better choice?
 
I think 254 can do lower impedance better than 258, correct? Going with the 258 would give me only 50wpc more power vs. 254 @4 ohms, correct?

He responded:

Yes, the SDS-254 X 2 bridged is a great choice. This would be allot more power then you’ll ever need.
 
Tom

As an FYI if you use my case you can go with one amp board and add the second later if you wish.  ALL the holes are already there.  Just a thought.

[celo]

As an FYI if you use my case you can go with one amp board and add the second later if you wish.  ALL the holes are already there.  Just a thought.

I would but I cannot really take them with me when we are moving overseas. I will take the modules with me in the plane and the case would be too big Plus, my wife already told me that she has an idea for a case. She wants to use a wooden wine crate/case. She will stain them, wood burn them and will make them look like an art piece so she says She loves projects like that so, I am okay with it. She can probably help me with the electronics part as well, she is good

I would like to know if someone could give me an technical explanation about using two SDS-254 vs. one SDS-258 specifically with my speakers. I will keep them probably forever, so I want to get something exactly for them. I am not after TOO much power but I just want to make sure that I build something that will handle the speakers in best musical way possible. I lived with the Aleph 3 so, good power even though it is 30wpc is enough for me. I just don't want the amp fall short for the Extremas.

BTW, thanks Neil! Although I am not sure if I still understand it 100% or not but at least I know little more about it now. I will read Nelson Pass's take too.

[matix]

I have already assembled a SDS258 amp kit.  Everything is going on fine.  I am thinking of adding another amp board for additional 2 channels to power the surround.  As this is for the surround only,  I do not really need the 258. Is it OK to buy the cheapest amp from Class D audio to  tap on the power supply from the SDS258 kit?