Digital amp comparison event.

Danny Richie · « **on:** 13 Jan 2006, 09:39 pm »

Hey guys,

I am putting together a jam on Feb. the 25th. It will be here at GR Research. We are located in Iowa Park, TX. That's about a 2 hour drive from Dallas to the North West.

Let me know if you are interested in coming. This one can be a lot of fun but will require more serious listening as comparisons and evaluations will be made.

The focus will be on the latest digital amps. We will try to spend as much time with each amp, as time permits, and run them on various speakers. It will be interesting to see (or hear) how they stack up to one another. I wonder which amps will rise to the top and which will be left at the bottom? Or will there be a bottom?

I have assembled a pretty good line up of amps. Some have already been committed and there are a few maybe's. If you know of others that you would like to have here then let me know.

Kevin Haskins of DIYCable is sending a couple of his Hypex based designs.

Brent Huskins from Media Design may either bring or send a Halcro MC20 and maybe a PS Audio GCC-500. He still has to confirm.

Ryan Tew of Red Dragon Audio says he thinks he can manage to get a pair of his Red Dragon's sent over.

Tom Maker of Edge Electronics said he will send some of their latest over and maybe a G.5.

Dusty of Channel Islands Audio says he is covered up with getting out orders but to check back with him in February and he might can get a couple of his out to us.

AV123 might be able to get us some working prototypes of their new X-amp. They are still working on it. I'll know shortly.

I have a friend that said he'd send me is Jeff Roland digital amps too.

Jason from NuForce responded with some questions about the system and who was going to be responsible for the amps.... and said he might be interested, but I have not heard back from him to confirm.

Are there any more that you guys would like to hear or compare to these top notch favorites?

I have a verity of speakers to use with these ranging from our new open baffle design, to a set of Epiphany 20/21's, to any other model that we offer. For some of you, hearing some of these speakers will be a real treat too.

I need to know in advance who plans to come, so let me know.

texasphile · « **Reply #1 on:** 15 Jan 2006, 03:17 am »

Count me in!

arthurs · « **Reply #2 on:** 15 Jan 2006, 04:57 am »

I'm in!

brj · « **Reply #3 on:** 17 Jan 2006, 03:35 pm »

Thanks for the offer, Danny! Count me as a definite maybe!

I'd definitely like to go, but I have one potential committment that needs to resolve itself yet.

Danny Richie · « **Reply #4 on:** 17 Jan 2006, 03:55 pm »

Brian, I was kind of hoping you could make it.

Looks like I will have a lot of amps here to compare.

Even Jason from NuForce finally responded asking where to send the amps.

Curly Woods · « **Reply #5 on:** 17 Jan 2006, 04:03 pm »

I have full knee replacement surgery on Feb 6th. I hope that my repaired leg will allow me to travel. I would love to attend.

brj · « **Reply #6 on:** 17 Jan 2006, 09:57 pm »

Quote from: Danny

Brian, I was kind of hoping you could make it.

Thanks, Danny... sounds like it will be interesting! I won't have a definite answer for a few weeks yet, but I'm going to try and make it.

Quote from: Danny

Looks like I will have a lot of amps here to compare.

Yes, and I thought of another variable that might complicate things... how sensitive are these amps to power conditioning? The range of products listed so far covers several different power supply implementations, from toroid to SMPS.

You still have Gary's new conditioner, I assume? A quick check with each amp on wall power vs. conditioner power might be a good idea, even if it does cost the group some time. (If I can make it, I can probably lug along the BPT if desired.)

Quote from: Danny

Even Jason from NuForce finally responded asking where to send the amps.

Good to hear. Any word from CI Audio?

PhilNYC · « **Reply #7 on:** 17 Jan 2006, 10:19 pm »

Quote from: brj

how sensitive are these amps to power conditioning?

We did a similar shootout of digital amps in the NY Rave (twice, in fact!)...and while we didn't try them thru power conditioners, we did find that they were all significantly improved to varying degrees by power cord upgrades over the generic stock cords.

Danny Richie · « **Reply #8 on:** 17 Jan 2006, 10:28 pm »

Quote

Yes, and I thought of another variable that might complicate things... how sensitive are these amps to power conditioning? The range of products listed so far covers several different power supply implementations, from toroid to SMPS.

Yep, I have been thinking about that.

Quote

You still have Gary's new conditioner, I assume?

Yes, that balance power supply is not leaving my system. I love it.

I figured we'd try them first from the wall so each gets compared equally, then try each one through the balanced power supply to see which are most helped or not.

Quote

A quick check with each amp on wall power vs. conditioner power might be a good idea, even if it does cost the group some time. (If I can make it, I can probably lug along the BPT if desired.)

Yep, and you can bring that if you want and you can finally A/B it with the Dodd unit.

Quote

we did find that they were all significantly improved to varying degrees by power cord upgrades over the generic stock cords.

What? I thought wire was wire? How can that be? NOT!

Just kidding.

Danny Richie · « **Reply #9 on:** 17 Jan 2006, 10:34 pm »

Quote

Good to hear. Any word from CI Audio?

Oh yea, Dusty said to check back with him in February. He might can get a couple out to us then, but right now he is too busy filling orders.

arthurs · « **Reply #10 on:** 17 Jan 2006, 11:39 pm »

Danny - I have a couple different PC's I could bring if you want to do some swapping.

Brian71 · « **Reply #11 on:** 19 Jan 2006, 09:48 pm »

Count me as a maybe.

Are the amps going to be hidden from view when they are listened to?
I think it would be interesting to throw one SS amp in the mix at random and see what people think (but don't tell them you are even doing it)

brj · « **Reply #12 on:** 19 Jan 2006, 10:30 pm »

If we add any more gear, we'll have to take up residence in Danny's living room!

I do like the idea of hiding the gear until the end, but I'd have no problem restricting the field to just class D amps. Honestly, if I could just identify which couple of class D amps most interested me (in Danny's room using his speakers and his gear), then I have a basis of comparison when auditioning other amps in the future - whether they are SS, tube or otherwise.

I'm curious about the degree to which the core technology influences the sound. For example, there will potentially be several Hypex based amps... will they all sound roughly the same, or will the power supply and other topology choices yield significantly obvious differences?

Danny Richie · « **Reply #13 on:** 19 Jan 2006, 10:51 pm »

Quote

Are the amps going to be hidden from view when they are listened to?

That is a good question. I have been thinking about that. I do have an old wall treatment panel that is a framed off sheet of open cell foam covered in fabric. It is about 6' long and 2' wide. I can stand it up across the floor between the speakers and hide everything.

Quote

I think it would be interesting to throw one SS amp in the mix at random and see what people think (but don't tell them you are even doing it)

That would be interesting and I could do that if time permits.

Quote

I'm curious about the degree to which the core technology influences the sound. For example, there will potentially be several Hypex based amps... will they all sound roughly the same, or will the power supply and other topology choices yield significantly obvious differences?

I am curious about that too. Most have already stated that they think it is all about the power supply on these as to how good they can sound.

Looks like we are drawing a pretty good group of guys for this. I may have to divide this up into two different days. I'll at least try to get the views of one local guy (maybe two) taken care of prior to the February 25th date (maybe on a weekday). I am going to try to spend as much time as I can with each amp using different speakers, cables, and with and without the Dodd Audio balanced power supply well before the get together so that when the time comes for the group to be there I can just play host.

Looks like a lot of eyes are going to be on this event.

Interesting huh?

TheChairGuy · « **Reply #14 on:** 20 Jan 2006, 02:05 am »

Quote from: Danny

Looks like a lot of eyes are going to be on this event. Interesting huh?

Very interesting here, Danny - quite a great and ambitious undertaking!

rustydoglim · « **Reply #15 on:** 20 Jan 2006, 08:44 pm »

Yes, blind test is good. Try to mix in a tube amp too.
A good A/B comparison should involve very neutral source, preamp, interconnect and speaker wires. But that's not aways doable or favorable to every amps.

Danny Richie · « **Reply #16 on:** 20 Jan 2006, 08:56 pm »

An update:

I got a call last night from Chuck Jones. He wanted to know if their amps could be included in the comparison too. I told him by all means. So there is a new Superphon digital amp on the way as well.

This is shaping up to be a fairly significant event for the manufacturers of these amps and for interested party's. It is also going to be very serious for some of these companies. So I am going to do my best to be serious about it.

I am leaning towards making comparatives of only three different amps at a time. Same music, or same pieces of music... then take a break and do the next three amps with different musical pieces. Then after all amps are heard, add balanced power to the mix or change speakers and change match-ups. New music again or let the group choose the musical pieces. Hopefully this will keep us from getting too tired of the exact same pieces over and over.

Also all listening will be blind. No one will know which amps are being used at any time. All will be hidden behind a 28" tall and 6' wide foam panel. All amps will be on good amps stands too. I may throw a curve ball or two and drop in a tube amp or solid state.

Now here is the part that I need some feedback on.

More people than I thought are wanting to come. Some may even fly in from up North... I want for everyone involved to have ample time to listen to these amps. So, I may have to spread this out over several days or consecutive weekends. This way we don't have to move small groups of listeners in and out of the listening room taking turns.

Looks like I might have a good handful of other industry professions here too. This are industry members not related to any of these amp companies, but if anyone from any of these companies wants to attend, they may. If they do come then I will respectfully ask that they be only observers.

So, as host of this deal I want to be as accommodating as possible to all that want to come.

I am locking down the 25th of Feb. for sure. I can also add the Friday before or the Sunday afterward if I need to. Or I can have a group the weekend after, maybe another Saturday.

Can you guys please give me some feedback on this?

Danny Richie · « **Reply #17 on:** 20 Jan 2006, 09:03 pm »

Jason, looks like you posted just before I could send this one that I was working on. Were you reading my thoughts?

Thanks for participating too.

brj · « **Reply #18 on:** 20 Jan 2006, 09:08 pm »

Danny, I'll try to give your questions some thought and respond when I have more time, but I had one other thought....

Obviously, these amps are going to cover a range of power outputs. If the goal is to evaluate the sound quality of each amp rather than raw power output, we'll want speakers that are efficient enough that even the lowest powered amp can compete fairly. I don't know think we have any flea powered amps showing up, but I don't know the power limits of all the amps listed so far. Are your primary speakers efficient enough that we can easily focus on sound quality?

(Or do you want to consider "grunt" as well?)

Thanks!

Danny Richie · « **Reply #19 on:** 20 Jan 2006, 09:21 pm »

It looks like most of these amps have plenty of power. So I don't think it will be an issue.

The speakers I have in mind to use have 91db sensitivity and are 8 ohms with a minimum impedance dip at 3,500Hz at 4.5 ohms. Open baffle design.

The other is about 94db sensitivity and is a pretty flat 6 ohm load with a minimum drop of 5 ohms. Epiphany 20/21's.