[corwin99]

That is a very sharp looking amp.. I'm quite interested to hear how this sounds! Email sent.

[Andrikos]

Very pretty amp Pat. Very understated and elegant.
I very much appreciate your blunt and logical approach.
As a fellow EE I detest marketing and snakeoilsmanship.
Maybe you can start a new thread so you can publish prices and stuff.
Thanks,

[art]

I'm short on time right now......Bubba the Plumber is trying to figure out where the break in my sewer line is. Appears that the line was routed by Bill Gates.....it makes no sense at all. He is fixin' to give up for the day, leaving me with......well, use your imagination!

The ICEpower amps are a bit lower than 10K. Mine is also 10K, but that is only because I use a coupling transformer. It works best into 10K. There is a JFET buffer after the transformer, so the only drawback is how frequency response is affected.

It is possible to make a semi-custom version with higher Z input. I would need time to make sure that I am satisfied with the results before I would be willing to do so.

If I do, all you would need to do is let me know.

Pat

[mac]

Pat,

I was on the verge of getting my hands on an iceH2o amp to try in my system when I realized that it's 10k input impedance requirement is at odds with my AR SP9 preamp that wants to see a far higher impedance.    I understand that this low input impedance is integral to the ice amp modules.

Is that also true in your design?   Can you provide more info about your amps?

Why not try the Hypex UcD400 modules?  Input Z is 100k.  They are claimed by some to sound as good or better than amps using the Ice modules.  A stereo amp built around the UcD400 modules will cost well under $600 but you'll have to assemble it yourself unless you pay someone to do it for you.  

[suits_me]

Everyone discusses prices here, whether the component has a circle or not. For example, the Scott Nixon stuff. If you feel queasy about posting it yourself, perhaps some member who emails you privately can let slip the numbers.

[IanVan]

...

Prices.........would you guys rather that I discuss that in public, or private?? I am not familiar with your forum and its rules, so I do not want to abuse the priviledge of being able to meet you guys here.

Please post prices. Many are interested, I'm sure.

Thank you.

[art]

I have made some measurements wrt increasing the input impedance. The way the design stands now, raising it from 10K to 100k does not seem like a good idea. Had I designed it differently, it would have been possible. There is a chance that a later version could incorporate such changes. It would depend a great deal on the appeal that it would have to owners of tube equipment. There are some units out for evaluation at this time. Perhaps it would be best to try to include some listeners that prefer the sound of tubes in next round.

Pat

[Ernest]

Pat sent one of the demo amps for my neighbor Ron and I to try out.  I went over to Ron's last night to have a look.  First off, the amp has the highest build quality I've ever seen in any audio product.  It is just freaking amazing how solidly it is built.  Ron took the cover off and that extends to the interior as well.  The ICE modules are nicely protected (and the outside protected from any EMI they give off) in metal cages.  If I am correct, each has its own power supply, and there is a huge transformer that they share.  The ART logo is etched into the front metal piece, but to a depth of like a quarter inch!  It's just an amazingly well built piece of equipment.

Ron hadn't hooked it up at all yet, so he did so, but had to use some generic speaker cable.  Also, his CD player is out of commission and so we had to use a CD hard drive recorder device as the source.  So the amp was cold, not broken in, had an average source, and crappy speaker wire.  So, well, it sounded like crap.  NOT!  It sounded very good, with great tonality, pace, soundstage, blah, blah, blah.  Ron thinks it's better the the Acoustic Reality amp he has (the original version I bought 2 years ago), and better than the prototype amp Pat gave him last year.  I think it was in that league but I am reserving final judgement until the amp is broken in and we can get a proper setup for it.  Then we'll do a head to head with Peter's amp and Pat's old amp and some stuff I've got sitting around here (Jungson Class A solid state amp, Dared tube monoblocks).

Pat's a master.  I already knew this.  But I'm excited to know that finally others will discover this for themselves!

Ernest

[mdconnelly]

Pat,

Thanks for checking out the possibilities of raising the input impedance.   While 10k is probably too low to work effectively with my AR SP9 preamp, I also don't think it needs to go as high as 100k.   The SP9 claims minimum of 20k and preferred at 60k.   My current Levinson amp is 47k (unbalanced) I think.

I would love to hear more about your amp and what future possibilities there might be with raising the input impedance enough to be considered with my preamp (or others similar).

Thanks!

[art]

20 K might work, I'll have to check.

Ernest:

Thanks for the kind words, but aren't you making it hard for me to do something better? Not that I won't try, but the expectations may be unrealistic.

OK, I'm being somewhat facetious.

Minor correction:

The front panel logo is machined, not etched, to a depth of 1/4". Yes, that did add a bit to the overall cost, but not as much as the input coupling transformers. (The price of which continues to rise, as does the ICEpower modules, with the rate of exchange continuing in an unfavorable trend.)

Part of the overall appearance of the amp was inspired somewhat by initial responses of the prototype units. We were trying to involve a sense of rounded smoothness, as well as taking advantage of the fact that no heat sinks are needed.

Pat

[art]

One day soon, I hope to get some measurements with a 20K load.

But.......is your preamp really not capable of driving a 10K load, or is it that the LF roll-off will be too much with a 10K load?? The input is transformer coupled, so the amp will not go down to 0.000002 Hz anyway. Poke your head inside of the preamp, and see what the value of the couling cap is. We can figure out the LF cut-off that way.

BTW.......I put together a website that may answer some of your questions. Someone has already pointed out that I forgot to state the gain. I'll change that soon.

http://home.att.net/~analog.research

Pat

[art]

I will be away for a few weeks, and will not be able to answer e-mail during that period. Just letting you know so that no one will think that I am ignoring them.

Pat

[Hantra]

I will be away for a few weeks, and will not be able to answer e-mail during that period. Just letting you know so that no one will think that I am ignoring them.

Pat

Pat:

Are you planning a 1000 watt version?  I don't think the 500 will get my speakers going that well.  I've tried the 201's from Rowland and they didn't do it.  I would like to try the 501's but I have decided they are just too much money.  

L8r,

B

[art]

Uh........I have a prototype unit.........not intended for commercial sale, just something to try out. Eventually, I will want to move it out. Probably at a very reasonable price. Perhaps you should send me an e-mail.

Pat

[art]

Ron hadn't hooked it up at all yet, so he did so, but had to use some generic speaker cable. Also, his CD player is out of commission and so we had to use a CD hard drive recorder device as the source.

This situation has been remedied as of a few weeks ago. Maybe you guys need to bug Ernest to go back and give it another listen. Assuming that his work schedule allows.

Pat

[art]

Fixin' to send out the experimental 1000 jobbie. The gang here will probably be interested in what you think. While I do not plan to make any of that version, I do feel that it will sound very close to the 500 W model.

Unless you really need to push an amp that hard!

Pat

[art]

I thought it might be a good time to answer some recurring questions that I receive. So, here goes........

Q. "Do you make amps with the ASP modules or the modules that use a linear supply?"

A. Both. The Velluto series uses the modules with a toroidal transformer supply. We feel that there is market for a more traditional style of amplifier for 2-channel applications. At present, we only offer the ASP in the Modulare 5-channel amp. These are still in limited production.

Q. "But could you make a 2-channel version with an ASP module?"

A. Yes. In fact, we have some custom units out for evaluation.

Q. "So, you do make custom amps?"

A. Yes. We have been making custom versions of all of our products for around 20 years now.

Q. "You mentioned that you could supply front panels in exotic wood. Any news in that?"

A. Ah, yes..........we just received our first batch (finally) of panels done in wenge. We may have to stick to woods that are more easily machined. The people behind the look of our products prefer that we use something other than generic oak, but it does seem easier to work with. Our logo is giving the CNC operators fits. So, there you have the news.

And finally........the one that I receive the most often:

Q. "Well, what makes your amps different than all the other guys building ICEpower amps? And why are yours more expensive?"

A. Well, lots of things. Without giving hints to our competitors how to improve theirs, I can say that we do more than just stick a module into a generic stock enclosure, wire up some connectors, and flog it off on customers.

We have an input buffer stage that others do not. We use this to compensate for the inherent high-frequency roll-off that all Class D amps have. We also use input coupling transformers which cost more than the ICEpower module. One reason is to prevent ground loops. May not be a problem in most stereo set-ups, but is becoming more prevalent in Home Theater systems. If you have ever had to contend with ground loop issues, you will appreciate that touch.

There are other little touches, and you will have to take my word for it. While I understand your curiosity on what makes ours what they are, a lot of it may more technical to explain than you really care to hear. I really don't think that you want to hear me go on and on about why we use this brand of diode in the power supply, instead of some other brand.

Do you?????? I bet not.

And do you want to hear some other manufacturer tell you why they think that I am wrong? I bet that they would, but only because they are a step or two behind. So, no............let's leave all the techno-babble out of the equation.

Anyway.........to end on a positive note.........

We are close to releasing the little 100 W mono amps. Small, light, stick 'em behind your speakers. Designed with the Home Theater market in mind, that needs something other than a big block of metal sitting in the room.  But it is also an excellent choice for a budget minded 2-channel system.

We hope to sell them for $500 each. A lot of performance in a small package for not a lot of money. We are sure that you will agree.

Pat

[art]

I was on the verge of getting my hands on an iceH2o amp to try in my system when I realized that it's 10k input impedance requirement is at odds with my AR SP9 preamp that wants to see a far higher impedance. I understand that this low input impedance is integral to the ice amp modules.

Is that also true in your design? Can you provide more info about your amps?

Ok.......I promised you guys some measurements........

Yes, in stock form, the ICEpower thingies are around 8K. I have a buffer, so it is higher.

I tried using a 50K load for the transformer, and it looks like a workable value. Assuming that all else falls into place, I can make this the stock value.

Fine print department:

The impedance will drop to around 10K at the higher frequencies. This is due to high frequency termination needed for the transformer. At low frequencies, you will not have to worry about any roll-off when using a capacitor coupled (tube) preamp. At the high frequencies, there will not be enough signal to cause any significant load current. So, everyone should be happy.

Right?

Next question?


Pat

[Hogg]

Hello,

     Is it possible to make an integrated amp from the Velluto?  Thank you.

                                                                           Jim

[art]

If you want the knobs on the front and the fancy 1" thick front panel: no.

Other configurations: yes, it could be done. Would entail making special PCBs for the switch/volume control, and moving the coupling transformers to this new PCB.

Pat