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Review: cMoy Headphone Amp Bass BOOST Edition - Page 2

post #16 of 192
never mind.
post #17 of 192
Quote:
Originally Posted by mrarroyo View Post
I was about to order one and finally try a Cmoy amp. Then I went to Ebay and read that it does not have a volume control, however on the pictures above you have one with a volume pot. What gives? can I purchase one w/ a volume pot?

Also I am not to interested in a gain switch provided the seller can set the gain at 3 out of the Cmoy. Is this doable? Thanks.
The OP requested a volume control and paid extra for it. The PCB is not designed for a volume potentiometer and I do not stock the parts right now. I happened to have some extra knobs and pots from building my Mini3. I will release a newer PCB after I sell off the rest of these. It will add an optional volume control.
post #18 of 192
No volume control? Is this supposed to be used with the headphone out instead of the line out? Wouldn't that be useless to the purpose of a headphone amp.
post #19 of 192
I have a short 8" extension with volume and a 30" with volume, so with one of those a person could use line-level outputs and control the volume with the cable.
post #20 of 192
Quote:
Originally Posted by ADD View Post
I always wonder where all the actual mints go with these things.
Good one!!!!
post #21 of 192
Quote:
Originally Posted by bonkon View Post
No volume control? Is this supposed to be used with the headphone out instead of the line out? Wouldn't that be useless to the purpose of a headphone amp.
+1
post #22 of 192
I got mine today. Shipping took less than a week . The build quality looks nice. One might wanna add some extra stuff to keep the battery in place.

I thought of giving this amp to my girlfriend to be used with her laptop and Sennheiser HD595. The gain is customized for the HD595, but I decided to test it with my Ultrasone Proline 650, since the HD595 hasn't arrived yet. I assume that the gain setting would fit the Prolines good enough for testing.

However, I was actually disappointed when I tried it on the laptop with my Prolines. The headphone out on laptop has some static noise that is almost not noticeable when connecting the phones directly. However, when using the amp the noise gets amplified and is really annoying when not playing music quite loud.

So this amp is not any good with a headphone out that is just a little noisy since the amp doesn't have any volume controller. If the amp would have a volume control one could set the volume on the computer to about 80% and then the noise would be smaller in comparison to the music. (output = noice + music (assuming most of the noise is static))

I compared Corda Move with this cMoy amp with the noisy laptop both connected to headphone out. With the Move the noise was just noticeable when not playing any music. I used about 80% of the headphone out volume and then controlling the volume on the Move.

I also tried the amp with my main computer. It worked better with my old soundblaster live card. Not much noise at all. However, the volume was quite load with the master volume close to zero. To decrease the digital volume controls doesn't seem to be a good idea to me. Then sound quality could be reduced.

The cMoy amp worked quite okay with my old Sony minidisc player. For some music it was an improvement over the directly using the headphone out. Music that was quite loud and compressed self sounded more flat when using the cMoy. I don't know if this could be caused by a digital volume control on the minidisc.

I think I will try to find a separate volume control and try it again with the noisy laptop. If that doesn't work I guess I'll keep it for the coolness.
post #23 of 192
Quote:
Originally Posted by bonkon View Post
No volume control? Is this supposed to be used with the headphone out instead of the line out? Wouldn't that be useless to the purpose of a headphone amp.
Yes, it's for use with headphone output. The cMoy is targeted as an entry level amp and that's how most people want to hook it up anyway. It works great with MP3 players. It's even fine with computers as long as you turn the volume down and have a decent signal to begin with.

I know a volume control is desirable (and mandatory for the higher quality line out signals), and will reduce hiss at low volumes, but as already mentioned, I will add a volume control soon.

Quote:
Originally Posted by Crossfeed View Post
I got mine today. Shipping took less than a week . The build quality looks nice. One might wanna add some extra stuff to keep the battery in place.

. . .

I think I will try to find a separate volume control and try it again with the noisy laptop. If that doesn't work I guess I'll keep it for the coolness.
I've since moved the padding for the battery and it now stays in place very tightly. Here's a quick shot:



As for noisy laptop signals, you're right, a volume control would help. However, garbage in = garbage out. Even with a volume control, the sound quality and noise present with integrated sound cards is undesirable. I personally place higher priority on maximizing the sound quality of my source before I bother amplifying a signal. The cheapest source I listen to, besides my iPod, is a SB Audigy 2 ZS.

I haven't tried it myself, but this Koss volume control may be what you need. Sennheiser also makes a nice control.
post #24 of 192
Last week I got a cmoy bass boost from John and I'm very happy with it. The build quality is solid and the battery lasts longer than my total airhead. The sound is tight, clear and brings out the soundstage.

The bass boast is great with my Shure E3C and iPod. Though, overkill with my AT A900 and HD600 which already have plenty of bass. I'm currently using them with my A900 and SB Audigy 2 and don't hear any hiss.
post #25 of 192
Quote:
Originally Posted by blackinches View Post
I've since moved the padding for the battery and it now stays in place very tightly. I'll edit this post later with a picture.

As for noisy laptop signals, you're right, a volume control would help. However, garbage in = garbage out. Even with a volume control, the sound quality and noise present with integrated sound cards is undesirable. I personally place higher priority on maximizing the sound quality of my source before I bother amplifying a signal. The cheapest source I listen to, besides my iPod, is a SB Audigy 2 ZS.
You might want to add some protection above the large capacitor as well. I for some reason pressed lightly against the amps top while playing and that was kind of scaring .

Yeah, I know the laptop as source sucks. However I think the sound card is good enough for the one that was supposed to use it . It sound quite okey when using my Prolines without amp except for playing really loud. I just want to add some extra power to be able to control the drivers better for a small cost. Not to amp the signal to play much louder...
post #26 of 192
Quote:
Originally Posted by Crossfeed View Post
You might want to add some protection above the large capacitor as well. I for some reason pressed lightly against the amps top while playing and that was kind of scaring .

Yeah, I know the laptop as source sucks. However I think the sound card is good enough for the one that was supposed to use it . It sound quite okey when using my Prolines without amp except for playing really loud. I just want to add some extra power to be able to control the drivers better for a small cost. Not to amp the signal to play much louder...
There is about 4mm clearance between the tallest capacitor and the lid in the current PCB. The board is also locked in place, so that should never happen again. And I leave my offer standing if you'd like a replacement.

Also, due to the high number of requests generated by the images of Kinky's amp, I've revised the PCB to accommodate an Alps RK097 volume control:



I will have a few of these boards in 2-4 weeks. Meanwhile, to save everyone time: Sorry, I cannot build any amps with a volume control until the new boards arrive. Patience, please
post #27 of 192
I got two "balanced" cMoys from John few days ago and "cooking" (burning in) well I did NOT want to have a volume pod for a balanced system. The volume is controlled by iTunes and it's working perfectly well. I will post pictures and some "review" after I get it burned in for few more days (~200 hours).
post #28 of 192
Just ordered one of these with the dual gain switch. Should be here by wednesday.
post #29 of 192
I just got this baby in the mail today, and I LOVE it!! The amp worked right out of the box, no problems what so ever. All the connections are tight, and both switches work properly. I have tried my dt770's, sr60's and my ksc75's with this amp, and I think the sr-60's sound the best. It sounds like an open dt770 with the bass boost on. I will add pictures later when I have the chance
post #30 of 192
This is NOT a formal review....because I know I suck at it

Consider this to be my commentary, observation, opinion, desire to share information, and story of a personal eargasm based on two matched cMoy amps built by John Seaber in a balanced configuration. Before I publish this...I had to think carefully because I did not want to become a possible laughing stock here at Head-Fi or just keep it silent and enjoy my music. When a person finds a rare elation that many other can also potentially enjoy...one just can't keep it quiet.

First of all, John Seaber (aka blackinches) is a top notch person with great product and one of the best service I have experienced here. The combination of great product and service (and responsiveness) goes a long way of earning my business. That's why he is building my next budget balanced rig: the balanced mini^3

Back to the amp....and my unorthodox configuration...

SETUP:
When I first read this thread by Iron_Dreamer (http://www.head-fi.org/forums/showpo...&postcount=10), that motivated and inspired me to test an idea of going balanced with my Senn HD650 and HD580 cans using my CIAudio's VDA2 DAC with VAC power supply.

I ordered two matching cMoys from John without volume pod and with gain switch. He carefully matched the two cMoys with matching resistors so the cMoys sound identical as possible. Since my intent was to use this purely as desktop amp, I took the battery out and used an expensive 24vDC output ELPAC power supply.




I connected a standard RCA to stereo mini cable from VDA2's right 0 and 180 phases and plug the mini stereo input plug to cMoy #1 (right side of headphone) and I repeated for the left 0 and 180 phase RCA from VDA2 to mini stereo input plug to cMoy #2 (left side of headphone). On the mini stereo plugs, the 0 phase was the tip of stereo plugs, 180 phase was the ring of stereo plugs, and ground was ground.




I modded the RnB's Grace 52 Senn cable from single ended to balanced TRS format to match the above stereo plugs signal orientation, where the - (minus) pole is tip of the TRS plug and the + (plus) pole is ring of TRS plug, per right and left side. Therefore the tip of TRS = 0 phase and ring of TRS = 180 phase per right and left headphone.



I plugged everything...double checked...triple checked...the connections. I turned off the bass boost on the cMoys. Set the amps to low gain. I lowered the volume on iTunes to lowest. I pressed to play Diana Krall's song, "Narrow Daylight".... I heard a loud POP and my drivers went dead.....JOKING;D

INITIAL SOUND:
When I gradually raised the volume on iTunes and heard Diana's song, "Narrow Daylight" for the first time on this setup, I thought the sound sucked. It was course, grainy, boomy, no soundstage, compressed sounding, piercing treble all over the spectrum,....I simply hated the sound. It wasn't even a decent music to me. I thought I wasted <$100 on amps, >$60 on ELPAC power source, and cut up a valuable RnB's Senn cable for nothing. I let it continue to play for few hours and heard little more on Diana's "`S Wonderful" and it sounded pretty good. The boomy bass tighten up and grainy sound was greatly gone. The soundstage returned little bit and compressed sounding was gone...and there were lots of details and channel separation. The first thing I noticed was the Senn650's dark veil sound was almost gone on the balanced configuration and it's the most powerful sound I have ever heard. The sound had potential so I let it sit and play music for almost 2 days straight without listening to it because I was too busy with work...and I had to tolerate my kids telling me I left the music on many times a day

BACKGROUND:
In this forum we read many people exclaiming, "OMG!!!", "eargasm" , "The best ever...", etc. when they are elated with quality of sound they never heard before. I rarely felt that way before with any of my amps from the past. I had many amps in the past. To list them, it goes something like this:

Stainless Steel "Toaster" MPX3 6SN7 with SLAM Adapters
Berning MicroZOLT (Sylvania Gold Brand 6201 & Russian 1960s 6SN7 tubes)
Updated Xin Supermacro 3V6 to near IV (AD797 with Buffers Bypassed)
Insanely modded X-CAN V2 (#1)
Xin Supermacro LE (ST-WA)
2005 MicroStack with Desktop Module (again)
Ray Samuels XP-7 (AD797)
MisterX XP Amp
Xin Supermicro IV
Rockhopper Audio's maxed out M^3 (Great amp!)
Upgraded (silver wire / blackgate caps) Gilmore V2-SE
Woo3 with enough NOS tubes to last until the next Ice Age
Mapletree Ear Purist + HD
Pinky modded X-CAN V2 (#2)
X-CAN V3 (few days...modded X-CAN V2 was better)
2000 Ok HP 100A hybrid Chinese amp
Headamp AE-1
Headamp Gilmore Lite V2 (twice)
Ray Samuels SR-71
Xin Supermini 3V3
Modwright CIAudio's VHP-1/VAC-1
Corda Aria
2005 Headroom MicroStack with desktop module
Zhaolu D2 with discrete head amp
Shellbrook Super Mini Moy

They all have one thing in common. They are all single ended. Out of them, the best sounding amps were my last two amps; microZOTL and Toaster MPX3. They made me think I would stop upgrading and gear swapping for good. Along comes Iron_Dreamer's comment about attaching two single ended amps to create a truly balanced system with VDA2 DAC absolutely intrigued me. I then began crudely test the idea by hooking up the ZOTL and MPX3 in a "balanced" configuration with hacked up stock Senn HD650 cable to make it balanced TRS format. After careful volume matching on two amps...it had potential and warranted a further practical research and experiment. I had made a promise to my wife that I will NOT keep more than two amps at a time so ZOTL or MPX3 had to go and stay around $1000 budget. I hated the idea of selling the ZOTL but I had to give it up and find it a very good home. I found a perfect home for it. Then I stumbled onto John's little bass boosted cMoy and that along with Iron_Dreamer's idea sparked this whole experimentation, revelation, eargasm, and "never go back to single ended system" mantra.

BACK TO THE SOUND:
After few days of burning in the cMoy amps...I didn't expect much as I was playing Diana's Live in Paris CD on iTunes. What can I say, the sound was amazing, powerful, the details, the channel separation was ....just WOW!! I had to look over to the two Altoids tin cans with rubber band strap on it and I just had to laugh out loud. This sound just can't be coming out of that!!! No way...no how!!! I compared the sound with MPX3 and the balanced cMoy and the balanced cMoy sound fuller, more organic, powerful, the bass went deeper, more detail, better channel separation, the treble energy was better than the MPX3 with vintage Sylvania 6SN7 and KenRad 6SN7 tubes, which was considered to be the best 6SN7 tubes for my old MPX3 6SN7 system. What is going on?!?! How can this be?! I am absolutely addicted to the balanced sound. I heard balanced rigs at the meets but never impressed me too much because the meetings are not the ideal environment to listen anything critically.

Instead of questioning too much at my elation and eargasm, I immediately decided to sell the MPX3 to fund it towards purchase of a "real" balanced system....Headroom's Desktop Balanced with Home module and dedicated power supply. (I promised my wife I would not buy any more cans for 6 months..hehe) The bad news was I had to wait two weeks plus for Headroom goodies to be built and shipped to me. Few days later, I decided to take Iron_Dreamer's original idea of going with all CIAudio's "balanced" system with two VHP2 amps and VAC power supplies. I canceled the Headroom order. The VHP2s and VACs should be here very soon

CONCLUSION...NO REVELATION:
It's true...SennHD650 turns into a different creature with balanced configuration. The sound it produces is probably the best bang for the buck in any headphones costing below $1000. Match that value with John's two matching cMoys that cost less than $100, another $100 on decent cables and power supply for the cMoys and you got your self a great balanced system on the cheap as long as you have a balanced DAC and easily modded balanced Senn stock cable.




When I get the VHP2s soon, I am planning to send out John's balanced cMoys to others who have VDA2 DAC and HD6** / HD580 so they can also contribute to "balanced system on a shoe string budget" opinion. I am NOT saying here that balanced cMoys can beat a $1000 balanced system or even a top notch single ended system. This information is to share a great idea inspired by Iron_Dreamer's and great product made by John Seaber (aka blackinches) in action at a great price/performance ratio. For me, I absolutely love the balanced sound...I can't go back to single ended

Final thought...I just want to thank Iron_Dreamer for his spontaneous idea of going balanced with two single ended amps that inspired me and John's cmoy to make it all happen in the first place.

Fiinally, Head-Fi's first story that's happy for your wallet

Next stop... balanced custom mini^3
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