D-100 Stereophile review

BradJudy · « **on:** 10 Jul 2005, 02:43 pm »

I just got my August Stereophile and was surprised to see Channel Island listed on the cover. They did a full review of the D-100 and while I haven't had a chance to read it yet, it looks like some good publicity for Dusty and crew. Congrats.

BradJudy · « **Reply #1 on:** 13 Jul 2005, 04:14 pm »

I read the review, measurements and Dusty's note yesterday. It looked like good stuff, a recognition of the quality and value CIA offers.

CIAudio · « **Reply #2 on:** 13 Jul 2005, 04:28 pm »

Wes Phillips really liked them even though the current limiting was set incorrectly. The follow-up in the September issue will show the proper measurements:

.027 THD
110w @ 8 ohms
200w @ 4 ohms
300w @ 2 ohms

JA was quite impressed

-Dusty-

BradJudy · « **Reply #3 on:** 13 Jul 2005, 10:24 pm »

Excellent.

Will your products be at either the AV123 GTG (I remember a few last year) or the RMAF this year?

CIAudio · « **Reply #4 on:** 13 Jul 2005, 11:15 pm »

Mark Schifter owns many of our products, but i'm not sure what he'll be using at the AV123 gig.

ModWright will be using the new D-200's at RMAF. I'm going to try to make it out there this year and may bring some other new goodies I've been working on

-Dusty-

BradJudy · « **Reply #5 on:** 13 Jul 2005, 11:58 pm »

Yeah, I've actually been meaning to borrow Mark's CIA headphone amp to compare to what I'm using now. If you come out to RMAF, I'll be sure to introduce myself.

mr_bill · « **Reply #6 on:** 14 Jul 2005, 12:50 am »

Anyone care to comment on what the review had to say?
Thanks,
Bill

NealH · « **Reply #7 on:** 14 Jul 2005, 01:49 am »

Generally big and spacious sound, superb separation between channels (as one would expect from monoblocs), deep taut bass, lots of airy detail. It was compared to a Coda S5 and aquitted itself well. Each amp had it's strengths and weaknesses, but all in all they were close.

Measurements for this amp, as well as most other switching output amps, were fair to middling.

CIAudio · « **Reply #8 on:** 17 Jul 2005, 05:47 am »

Quote

Yeah, I've actually been meaning to borrow Mark's CIA headphone amp to compare to what I'm using now. If you come out to RMAF, I'll be sure to introduce myself.

Would be nice to meet you there Brad.
There will be a few rooms using our D series amplifiers. You'll probably find me hangin out with Dan in the ModWright room.

-Dusty-

CIAudio · « **Reply #9 on:** 17 Jul 2005, 06:00 am »

Quote

Measurements for this amp, as well as most other switching output amps, were fair to middling.

The "fair to middling" measurements were due to setting the current limit on the amplifiers when cold. After their 1/3 power for 1 hour warm-up, they would current limit prematurely. The D-100's measure (and sound) better than any we've tested.

JA's measurements of the same amplifier (correctly set up) will posted in the September Stereophile follow-up. They agree with our numbers of
Less than .030 THD
110w @ 8 ohms
200w @ 4 ohms
300w @ 2 ohms

Tim S · « **Reply #10 on:** 19 Jul 2005, 01:04 pm »

So were the only measurements they got wrong the power handling capabilities?

Tim

CIAudio · « **Reply #11 on:** 19 Jul 2005, 03:07 pm »

Quote

So were the only measurements they got wrong the power handling capabilities?

They didn't really get anything "wrong". The tested power output into 2 & 4 ohms was below spec because we did not set the current limiting properly. Once this was fixed, their measurements easily exceeded our specs.

For distortion measurements, Class D amplifiers can "trick" analyzers if the proper filter is not used. They used an older AP System 1 with their own "home brewed" active filter. The industry standard is to use a newer System 2 with AES-17 filter or add the AUX-0025 passive filter (specifically designed for Class D measurements) to their Sys 1.

Their original measured THD was between .05-.1 depending on temperature and load. Their new measurements range from .027-.0285 using the same "home brew" filter.

-Dusty-

BradJudy · « **Reply #12 on:** 17 Aug 2005, 03:45 am »

Got the new Stereophile with the revised measurements. Good work. I also heard some high praise for the D-100 from a friend this weekend.

CIAudio · « **Reply #13 on:** 17 Aug 2005, 12:36 pm »

Thanks Brad,

I think there is also a review of our VHP-1 Headphone Amplifier & VAC-1 Upgrade Power Supply in the September issue...being on the west coast, It'll probably be a few days before I get my subscription copy

-Dusty-

BradJudy · « **Reply #14 on:** 17 Aug 2005, 01:25 pm »

Hmmm...I don't recall seeing your headphone amp reviewed. I haven't had a chance to read through it totally, but I don't see it listed.

CIAudio · « **Reply #15 on:** 17 Aug 2005, 02:41 pm »

The VHP-1/VAC-1 review was slated for the Sept. issue, but from what they told me this morning...it will be in the October issue due to some scheduling problems.

-Dusty-

BradJudy · « **Reply #16 on:** 17 Aug 2005, 05:37 pm »

I'll keep an eye out for it - I imagine you'll be seeing more business with nearly back-to-back major reviews.

One of these days I'll steal Mark's VHP-1 and try it out.

Bails · « **Reply #17 on:** 22 Aug 2005, 09:28 pm »

The D-100 review is up on Stereophile's website now.

Bails · « **Reply #18 on:** 6 Sep 2005, 05:55 am »

Quote from: CIAudio

They didn't really get anything "wrong". The tested power output into 2 & 4 ohms was below spec because we did not set the current limiting properly. Once this was fixed, their measurements easily exceeded our specs.

For distortion measurements, Class D amplifiers can "trick" analyzers if the proper filter is not used. They used an older AP System 1 with their own "home brewed" active filter. The industry standard is to use a newer System 2 with AES-17 filter or add the AUX-0025 passive filter (specific ...

Does this mean that a batch of the D-100s were set incorrectly, or was it only the Stereophile samples? If it applied to early production models, can you advise which serial numbers are affected and how the issue can be rectified?

Thanks.

CIAudio · « **Reply #19 on:** 6 Sep 2005, 01:15 pm »

Quote

Does this mean that a batch of the D-100s were set incorrectly, or was it only the Stereophile samples? If it applied to early production models, can you advise which serial numbers are affected and how the issue can be rectified?

We answered this in the Critics Circle and have copied it below

There are a couple of reasons for the premature current limiting:

#1 In our haste to get the first samples to Stereophile on time, we were not able to burn them in and properly set the current limit.

#2 The D-100 has undergone several changes as we're always trying to improve our products.

The samples reviewed by Stereophile were our first revision and sent to them several months ago. They exceeded their 8 ohm spec, and would meet their 4 ohm spec when cold, but the current limiting was temperature sensitive and would prematurely limit into lower loads after warmed up. We readjusted these same amplifiers and then they met our spec of 175w into 4 ohms.

Quote

Current models use a newer design in which the current limiting is not temperature sensitive. They also have other improvements to lower distortion and increase power output into 4 ohms (200w) and 2 ohms (300w).
This was measured by JA and results are printed in the Sept. issue Stereophile follow-up.

Latest versions can be identified by 8 screws on the rear heatsink, early versions had a total of 6. For those who wish to update to the latest version, the pair of amplifier modules and heatsinks can be replaced at a cost of $350. This is only necessary if you have a difficult speaker load (below 4 ohms).

-Dusty-