Review: cMoy Headphone Amp Bass BOOST Edition

[Caribou679]

Originally Posted by HeadphoneAddict

I think you're gonna upset a few people about this.

This particular CMoy bass boost does use a capacitor that might need burn-in or time to "form". The builder does say it will work well without a cap. On this particular amp I can say it has changed a little, acheiving a mildly to oderately improved soundstage vs new. I reported on this earlier.

However, I can vouch for, affirm, or attest to the fact that my iBasso D1 and my PenguinAmp Royal have had even more significant changes as they put more hours on the clock, they use significantly bigger caps...

My intention is not to upset people, but on a forum discussions can bring counter ideas.

On the amps I am using I do not saw significant changes with burn-in. However with IEMs and headphones, yes I notice a noticeable/significant change for the better, so an improvement.

Under better circumstances,and a more stable base, I will have a tubes amp and will be able to experience it myself.

I am interested in getting this bass expanded amp to experiment the change in sound it brings.

Currently using an amp with closed earphones,RP22, to listen to Beethoven's symps and Opeth growls!

Anything that can help to improve these experiences is welcome...

regards,

[neogeosnk]

Originally Posted by sbulack

As the burn-in has progressed, the sound of the Bass Boost has become clearer, cleaner

How long do you guys burn in your cmoy amps for ? Real interested to see what the "standard" burn in time would be. I believe burn in for cmoy does have an effect btw. You're not crazy. Even solid state parts tend to settle, IMO.

[HeadphoneAddict]

I burned mine in as I used them - with the exception of my iBasso D1 which I ran for 250 hours with occasional checks on the sound, and the exception of my Tomahawk that had 700 hours on it when I got it.

[sbulack]

Originally Posted by neogeosnk

How long do you guys burn in your cmoy amps for ? Real interested to see what the "standard" burn in time would be.

The improvements that I heard happened during the first 60 hours or so of use. Beyond that, I haven't heard any further development of the sound through it.

What I very much enjoy about the sound through the cMoyBB is its cleanness, clarity/transparency, openness/spaciousness which I find to be very refreshing to my ear and my listening. I've got two home amps and a variety of portable amps (including the TTVJ Portable Millett Hybrid Amp), all of which I enjoy very much as listening instruments. The cMoyBB fills another, and valued/enjoyed, listening niche for me - through its high-quality simplicity - much like well-prepared sonic lemon ice.

[Baines93]

Blackinches, how are you doing building this newest batch? And what will the final price be?

-= Matt =-

[blackinches]

Everything is on schedule. I have two v1.55 prototypes. The bass boost switch will now be wired separately from the PCB.



I will have all the parts to resume sales in stock by Friday, October 5th (or possibly as soon as Monday the 1st). I am happy with the latest board, but before I release the final version I will be sending out one of the v1.55 amps for customer evaluation. I cannot add any more space between the jacks and volume knob and I want to make sure it is suitable from the customer's perspective. It's a definite improvement over the last version.

I have not yet decided a final price. Because of the added volume knob, I am considering eliminating the option of dual gain. Most of my customers end up picking one gain and leaving their amps set to that option constantly. With the volume knob, the function is even more useless.

Would anyone be interested in buying the bare PCBs and/or kits? While I enjoy doing this, demand is higher than one person can handle.

[Baines93]

I would definatley be interested in testing/evaluating one.... Depending on price, i would also be interested in making a kit..... I could have made a cmoy, but wanted bass boost, so yeah, a kit would be great, so long as it comes with everything, and depending on price of the kit vs profesionally made.....

I would definatley be interested in testing/evaluating one though.... Let me know if i can please!

I could give you some of my impressions on how it is to use, and how i think it sounds.....

If you do let 2 people do some evaluations of the new board, Please can I be the first one on the list!

-= Matt =-

[blackinches]

The first v1.55 amp has already been claimed and I will hold on to the other for my own analysis.

However, I will have a used v1.50 available this week. PM me if you are interested.

[HeadphoneAddict]

Originally Posted by blackinches

Everything is on schedule. I have two v1.55 prototypes. The bass boost switch will now be wired separately from the PCB.



I will have all the parts to resume sales in stock by Friday, October 5th (or possibly as soon as Monday the 1st). I am happy with the latest board, but before I release the final version I will be sending out one of the v1.55 amps for customer evaluation. I cannot add any more space between the jacks and volume knob and I want to make sure it is suitable from the customer's perspective. It's a definite improvement over the last version.

I have not yet decided a final price. Because of the added volume knob, I am considering eliminating the option of dual gain. Most of my customers end up picking one gain and leaving their amps set to that option constantly. With the volume knob, the function is even more useless.

Would anyone be interested in buying the bare PCBs and/or kits? While I enjoy doing this, demand is higher than one person can handle.

In the non-volume control version I have found the gain switch to be very helpful switching between IEM's and Sennheiser headphones. It also helps reduce hiss with very efficient IEM's.

So, basically you are looking for a partner to put together kits for you vs selling the amps as a kit? I wonder if I have enough time and energy (or skill) since I retired early on medical disability last month. I DO know a very skilled engineer, David, at www.proecm.com who may be interested.

[blackinches]

Originally Posted by HeadphoneAddict

In the non-volume control version I have found the gain switch to be very helpful switching between IEM's and Sennheiser headphones. It also helps reduce hiss with very efficient IEM's.

Right, for the non-volume control edition, that is precisely why I offered the dual gain switch.

With a volume control, the signal is much easier to control. Mathematically, a single gain amp will indeed have a fixed gain if the input voltage is measured at the input capacitors. The actual input signal is the output signal of the audio source. In my opinion, this is a more appropriate theoretical reference point for calculating gain, since gain = Vout/Vin. The volume control changes the amplitude of Vin, thus, directly affecting gain.

The dual gain switch in my amps changes the gain according to the following equation:

Gain = Av = 1 + R4/(R3a+R3b)

Clearly, the dual gain switch has an entirely different relation to the input signal. While it has a similar effect and could be used as an option to alter the rate at which the volume increases/decreases, I think it's best considered a $5 method of altering a variable that will already be controllable.

So, basically you are looking for a partner to put together kits for you vs selling the amps as a kit? I wonder if I have enough time and energy (or skill) since I retired early on medical disability last month. I DO know a very skilled engineer, David, at www.proecm.com who may be interested.

Thanks for the offer. Some of my engineering friends have offered to help assemble amps. Anyone who can solder should be able to assemble one. I'm mainly interested making my amp available to DIY'ers for two reasons:

1) It will make the amp cheaper.

2) I feel it is important to feed the DIY market to support engineering creativity and progress.

[Baines93]

EDIT:

Oh, i didnt get it

Oh well....How much will the used one be? Does it have a volume control?

[cchaeha]

would these drive 250 ohms phones well?

[blackinches]

Originally Posted by cchaeha

would these drive 250 ohms phones well?

Yes, it should be no problem.

[Schalldämpfer]

I might be interested in having one as a backup.

If I specify it for my HD-650 and PROline 750 gain switch, default tin can, no light change, how much would it run me? And by when can it be shipped?

[marshes]

my dt770 80 ohms should be arriving friday, the same time hopefully blackinches gets all his parts for his amp. Wonderful timing, super excited to start my head fi journey. Hopefully once i have an abundance of money ill turn them into darths!

Sent from my iphone!!