Digital amp comparison event.

rustydoglim · « **Reply #20 on:** 25 Jan 2006, 08:02 am »

Can you post a list of the preamp, speakers, cables etc (except amps) that you plan to use at the event?

Oh, I think we should also sort of standardize on some evaluation criteria and provide notepad for people to take notes. It can be very confusing and tiring after a while. For example, rating from 1 to 10 on dynamic, musicality, transparency, etc for people who want to rate the amps. If they don't care about rating the amps, then leave a comment section.

We should also make sure only high quality recording and CDs are used for demo. We should avoid having people randomly submit their CDs during critical listening sessions. May be even ask people to send in their CDs ahead of time.

It is a good idea to include a WORLD CLASS tube amp and solid state amp in the mix.

Oh, how do you deal with toeing speakers for sound stage adjustment? Nuforce amp has wide sound stage and sometimes people toe-out the speaker more than usual depending on the sitting position and room size.
Other amps might have different requirement.

rustydoglim · « **Reply #21 on:** 25 Jan 2006, 09:38 am »

One more thing. How to handle amps with different gain? Hey, some amps have published gain of X but it is actually X+/-1
Do we need to play a track for calibration (meaning adjusting the volume level) so that all amps are played at the same level?

Oh, since the amps are going to be out of sight, to avoid mix up, each should have a label attached to it (with a string so it can be displayed in front of the cover) so people can associate what they hear with the mystery amp's label. It gets confusing if we just go by random order.

Does alcohol affect hearing? What you hear before and after you get tipsy could affect the judgement.

Sorry, this seems to get out of hand

art · « **Reply #22 on:** 26 Jan 2006, 05:35 pm »

I am just down the road a ways............hint, hint.

Only have -250s around this week.

Pat

Danny Richie · « **Reply #23 on:** 30 Jan 2006, 05:29 pm »

More specifics about the test system and method of comparison will be coming shortly. I may just start a page on our web site covering this whole event and post links to it on various forums.

A few amps have already made it in. NuForce amps and an Edge amp are already here. More to follow...

Danny Richie · « **Reply #24 on:** 30 Jan 2006, 07:09 pm »

Hi Pat,

I am sorry that I overlooked you. I guess I didn't realize that you were producing class D amps.

I just checked your site and it looks like you have some very nice looking products there, and right in my own back yard.

You are more than welcome to participate. You are not only welcome to send amps but you can come too if you like. It looks like you are only a couple of hours away.

HumanMedia · « **Reply #25 on:** 31 Jan 2006, 01:45 am »

Any luck yet with getting the Channel Islands amps for the event?

(I know they are currently sold out and waiting for some chassis coming in a week or two.)

HumanMedia · « **Reply #26 on:** 31 Jan 2006, 01:45 am »

duplicate post

HumanMedia · « **Reply #27 on:** 31 Jan 2006, 01:45 am »

duplicate post

Danny Richie · « **Reply #28 on:** 1 Feb 2006, 05:20 am »

Quote

Any luck yet with getting the Channel Islands amps for the event?

No luck yet.

I am please to announce that Pat from Analog Research Technology will be sending an amp up too.

Looks like quite a line up.

avta · « **Reply #29 on:** 2 Feb 2006, 12:11 am »

Danny:

I wish I could make it from California but that isn't possible. I wonder if you would consider contacting one or more of the popular magzines and/or web sites that review audio equipment e.g The Absolute Sound, Stereophile, 6Moons etc. They have lots of experience comparing systems and might be able to give you some ideas about what to do and not do to in your testing. Best of luck. I'm looking forward to the comparisons.

Guy

Kevin Haskins · « **Reply #30 on:** 2 Feb 2006, 12:59 am »

Just wanted to drop in here and give some details on what I'm sending Danny for the event.

I'm going to divert one of our amps that are out on user demo to Danny for the week of the event. Details on the amplifier are fairly simple. It is a standard 2-channel Hypex UCD-400AD amplifier with the Hypex HG Power supply, and softstart. It is bone stock without any modifications so it is representative of a stock Hypex unit with a 500VA transformer. It should be good for the 200W @ 8 Ohms & depending on how you calculate the numbers at least 350W @ 4 Ohms. We have been selling this unit for $1400 each.

There are a few things we are going to be changing in the upcoming models that may have some impact on subjective performance. I wish I had something ready for the event but I'm just not going to have the newest version available in time.

The changes from an engineering standpoint are minimal. Subjectively it may be large or small depending on who you ask, loudspeakers used, system dynamics etc....

* Powering the opamp buffer with a dedicated low-noise regulated power supply.
* Replacement of the DC blocking caps
* Replacement of the cap in the LC output filter
* High quality 1KVA transformer with goss shield, & electrostatic shield between primaries and secondaries.

We will offer both the stock unit, like the sample I'm sending to the event and the modified version at a higher price point (probably about $1800 as described).

Cosmetics will change only slightly... the logo is moving to the center of the aluminum 'X' and we are building it out of thicker material. The chassis is also going to be 1.5" deeper as we are making room in this chassis for up to five channel UCD400 builds and seven channel UCD180 builds. We had Hypex develop us a power supply for up to five channels that has both DC output protection & silent power up/down cycles. Essentially it is a Hypex HG power supply design stretched to allow room for 100,000uF of capacitance and five channels of output protection.

Wish I was close enough to come to the event. Sounds like a lot of fun in Texas.

art · « **Reply #31 on:** 2 Feb 2006, 05:13 am »

The "professional reviewers" would be the last people that I would ask for anything.

I hope to send a -250 ICEpower amp, with conventional supply. As there will be others using the SMPS, it migh be good to have a different genre. However, it might be a more reliable test to use modules with the same power rating. So......if anyone knows what the power rating of the ICEpower amps will be, let me know. I can put a -500 together in short notice.

The only UcD amp around today is a -180 proto. I can send that, unless you feel that there will be too much clutter that way. No -400s in stock, and probably no sense to send 2 that would be virtually the same.

(Besides.....I am changing the PCB on those. Again.)

Pat

Chan · « **Reply #32 on:** 3 Feb 2006, 11:25 am »

Danny,

Have you considered to include Tact 2200 in your list?

Danny Richie · « **Reply #33 on:** 3 Feb 2006, 03:26 pm »

I have not pursued acquiring one for the event but have no reservations against using one in the event. If someone would like to send one then I would be glad to include it.

mrmusic · « **Reply #34 on:** 6 Feb 2006, 12:32 am »

We at Superphon thought it might be a good idea to let anyone interested in the switching amp shootout know exactly what we sent to Danny. Our amplifier is a prototype based on the Hypex UcD 400 module. We have stripped the input stage and are using only the comparator and output. Our unique input stage features very linear phase vs frequency to well beyond the audio band. It is locally shunt regulated and has a direct coupled input. We are using a more or less conventional power supply with a 500VA transformer and separate rectifiers and caps for each channel. Output filters are stock and there are no ultra exotic parts in there (yet!). This amp is one of several under consideration for production, so we are looking forward to the shootout results. We would like to extend our appreciation to Danny for hosting this event, and to the participants for thier views and opinions. Have fun, and lay off the sauce until you've heard ours!

art · « **Reply #35 on:** 7 Feb 2006, 03:52 am »

Hmmm....strip the input stage and use a shunt regulator...........

If I didn't know better, I would say that you have peaking into our lab at night.

Just joking, Chuck!

Pat

audiojerry · « **Reply #36 on:** 7 Feb 2006, 04:50 am »

How many different amps and different speakers?
Sounds like great fun, but I don't see how you could possibly achieve any reasonable comparison with so many amps and other variables.

Since you are going to do it anyways,

, hopefully you can take a very disciplined and structured approach.

As a suggestion, you might want to spend a reasonable amount of time, say at least an hour or more with three amps at a time (two at a time if you think there will be enough time) , played with the same material and same speakers. Try to pick one winner from each trio, then pit the winners against each other in another elimination.

If you are going to use different speakers, start the process over again with different speakers.

Same thing if you insert any other components into the comparisons.

Danny Richie · « **Reply #37 on:** 8 Feb 2006, 12:20 am »

Quote

How many different amps and different speakers?

I am going to try to limit it to two different sets of speakers. We will have quite a few amps to try.

Quote

Sounds like great fun, but I don't see how you could possibly achieve any reasonable comparison with so many amps and other variables.

So far I have amps from three different companies already here. All three of them are very different. I can tell the difference in all three of them a few seconds into one song. I wonder where the rest will fall in?

We will take a very disciplined approach and take this very seriously.

Quote

As a suggestion, you might want to spend a reasonable amount of time, say at least an hour or more with three amps at a time (two at a time if you think there will be enough time) , played with the same material and same speakers. Try to pick one winner from each trio, then pit the winners against each other in another elimination.

I have had something similar in mind.

mrmusic · « **Reply #38 on:** 8 Feb 2006, 04:25 am »

Quote from: art

Hmmm....strip the input stage and use a shunt regulator...........

If I didn't know better, I would say that you have peaking into our lab at night.

Just joking, Chuck!

Pat

Thank's Pat, i did'nt realise the TROLL had escaped from the basement again!

art · « **Reply #39 on:** 10 Feb 2006, 11:46 pm »

The troll is over at DIY Audio, collecting the facts on shunt regulators.

(Unfortunately, that really isn't a joke, but not something we want to discuss here.)

Pat