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a review of Biosciencegeek Cmoy amp

post #1 of 13
Thread Starter 
Bioscience Geek Cmoy Amp Review

In my search for portable audio nirvana on a limited budget I did allot of research on the net before I decided on components. I already owned a 2nd gen 1gig i-pod shuffle, (why the shuffle? See this article Shuffle's Got a Secret Shuffle's Got a Secret - Columns by PC Magazine) and JVC marshmallows, hardly the stuff of audiophiles. To make a long story short after an extensive search I choose the Altec Lansing IM716 for headphones, and a Biosciencegeek amp (op amps OPA2227 and LM4562.)
For this review I used Cheskey’s Ultimate Demonstration Disk (readily available on the net). This is a really fun audiophile quality cd. I think it would be really interesting if other amp reviewers used a recording perhaps this one for reviewing to provide a common baseline for reference.
For this review I used a 2nd gen 1gig i-pod shuffle, Altec lansing IM716 (un-modded, set to high def mode), and the Biosciencegeek amp on low gain with the LM4562 op amp. I prefer this op-amp, as it is more suited to my taste. The OPA2227 is a wonderful op amp as well and may be preferred to the LM4562 by users who find the level of detail presented by the LM4562 fatiguing. I listened to each track twice at similar levels once with the amp and once straight from the i-pod to provide a comparison. As well on a few selected tracks I tested the high and low gain settings and compare how they impacted sound quality. This is another feature of the Biosciencegeek amp that differentiates it from others available as many amp builders build with an arbitrary gain setting, often without specifying the setting to end users.
With any review I think it is helpful to know the biases of the reviewer. I enjoy a wide variety of music however when I listen I like to hear details (he had 4 quarters in his pocket when he was singing level of detail.), having said that I prefer as close to neutral presentation as possible.

Cheskey’s Ultimate Demonstration Disk

High Resolution - Spanish Harlem
I-Pod: Rebecca’s voice is veiled and one-dimensional. The shakers in the song are fairly distinct however appear extremely veiled when compared with the amped version. Depth is there however is non-existent when compared with the amped version. The pluck of each string of the bass is blurred and there is a distinct lack of resonance. Simply the bass is muddy and non-distinct
Rebecca’s voice is ephemeral and completely fills the soundstage. The shakers in the song are crisp and distinct; you can hear each individual bead in the shaker. Depth is greatly improved with the amp the reverberation of the performance is palpable. The pluck of each string of the bass is distinct as is resonance of the sound off the instrument.

Depth-If I Could Sing Your Blues
I-Pod: Sarah’s voice is recessed and dull and the reverberation is lackluster. The plucks of the guitar are present however once again not as distinct as when amped as well the guitar is muted and lacks the full tonality evident in the amped version. As well the trumpet, and cymbals are lost in a muddy veil.
Amped: Sarah’s voice is strong and the distinct the reverberation of her voice is greatly improved over the straight version. The plucks of the guitar are present and each pluck is distinct as well the full tonality of the guitar is much more evident in the amped version. The trumpet, cymbals are separated on the soundstage beautifully.

Atmosphere-Maiden Voyage
I-Pod: very warm, maybe to warm, with a noticeably compressed soundstage. The voice is muted and lacks any dynamic range. The bass is constricted and muddy. The drums and cymbals are dirty and lost in the compressed soundstage. Overall a very dry presentation of this track
Amped: The soundstage is very expansive and warm. The instruments are distinct and discretely placed. The voice is much more present and dynamic. The bass is full, perhaps could be a little more present and warm. Drums and cymbals are presented nicely.

Midrange Purity-Grandma's Hands
I-Pod: This track sounds extremely thin the Finger snaps are almost non-evident voices leave me wanting to quickly switch to the amp even before the song is over. Sad and non-involving
Amped: (Low Gain) Oh yes! This is what I want. Very real finger snaps located beautifully on the soundstage. The soundstage is expansive and distinct. The voices are very dynamic and exciting. This track is one of the most obvious comparisons of amped versus un-amped. WOW!
(High Gain) The hiss from the i-pod is very present and the headroom is greatly increased. The fingers snaps are moved forward in the soundstage with less of a flesh and bone presence. There is some minor distortion of the vocals on more demanding highs in the presentation

I-Pod: The introduction of the rainforest effect is weak and un-demanding, particularly the rain stick which sounds hollow and unreal. The voice is soft but present. The cello is placed nicely on the soundstage however lacks the distinctiveness and reverberation apparent in the amped version. The soundstage is compressed and muddy. Listening to the amped version there are instruments present that are completely lost in the un-amped version.
This rainforest effect is natural, the sound of the rain stick is full and distinct you can hear the individual beads running down the stick. Bass is pronounced with a depth and complexity completely absent from the un-amped version. The voice in this presentation is much more pronounced and full. The cello fills the space with simply incredible reverberation. Very expansive soundstage!

Transparency-Played Twice
I-Pod: The piano sounds hollow and weak with little or no depth. Bass is weak and uninteresting, the pluck of the bass while present is non distinct. The soundstage is very compressed in this presentation of this recording. Cymbals are fairly present however lack the airiness present in the amped presentation.
Amped: piano warm and percussive with good transient attack. Bass is full and each pluck of the string is unique. There is a large expansive soundstage present with an airy feeling of depth. Cymbals are a tad harsh however the feeling of an airy and delicate presentation remains evident.

Presence- Ask Me Now
I-Pod: The sax in this presentation is not placed distinctly in the sound stage. As well the mechanical click of the keys are not discrete but blurred. Reflection or any feeling of depth is completely lacking.
Amped: The sax in this presentation occupies a distinct place on the sound stage. The mechanical click of the keys is so accurate you can hear the different pressure used to compress each key. The reflection and depth in this presentation is rich

Visceral Impact-Sweet Georgia Brown
I-Pod: The feeling of excitement is a muted version of the amped presentation. Again the sound is weak and hollow. The soundstage while present is compressed with much of the detail lost. The bass guitar’s sound on the i-pod is blurry and un- inspiring.
Amped: The feeling of excitement is palpable in this presentation. The attack of the drum kits, bass, sax is exhilarating. Details are present which are totally absent in the un-amped version. The soundstage is vast and distinct.

Rhythm & Pace- I Love Paris
I-Pod: A lackluster performance, which does not convey the energy or excitement of the musicians on this track. The soundstage while present is compressed with much of the detail lost. The bass guitar’s sound on the i-pod is blurry and un- inspiring. The electric guitar on this track is hollow and boring
Amped: Conveys the attack and pace of the musicians beautifully. Details are present which are totally absent in the un-amped version. The soundstage is vast and distinct. The electric guitar is fast and exciting.

Focus-Flute Concerto in D
I-Pod: The flute is a muted version of itself in this presentation. The total lack of soundstage and focus is utterly apparent. The transience of each note of the flute is absent.
Amped: This presentation is full and lively. The soundstage is distinct and expansive the flute is present with each note occupying its own space. The breathe of the flute player is evident where it is lost in the un-amped version.

Holographic Imaging-Festival Te Deum
I-Pod: The presentation of this huge recording on the i-pod is a sad weak version compared with the amped version. This presentation left me begging for more, more of everything. The mighty peaks are humble molehills with the i-pod. There is no sense of the majestic setting of this recording with the i-pod
Amped: (Low Gain) I’ am right there in the cathedral. Sitting in the pews looking up at the choir. I can feel the mighty peaks presented in this recording. However in the introduction to this recording the narrator warns that “there are mighty peaks, which can humble many a system.” And indeed they did humble this amp. At a comfortable listening level there was considerable distortion. Having said that when I reduced the volume the peaks where present and not distorted, they were just not at the volume I would have enjoyed. The i-pod did not suffer from this distortion, as it was simply incapable of producing the mighty highs present in this recording.
(High Gain) Yet again the hiss from the i-pod is very present and the headroom is greatly increased. Very detailed! Vocals are much more present and clear. The organ has more authoritative presence. Again at my preferred listening level the considerable peaks are distorted. However after adjusting the volume to a level where the distortion disappears this presentation is preferred over the low gain presentation.

Transients-The Royal March
I-Pod: This recording is very hollow sounding on the i-pod. The drums sound is taught and quick but flat compared to the amped version. Horns are clear and quick but lack the excitement present in the amped version.
Amped: The amp presentation of this recording is very clean, quick, and precise. Drums are taught with great depth and resonance. Horns have a crisp and powerful bite, very exciting.

Bass Resonance
I-Pod: The pluck of the standup bass is present but not as precise as the amped version as well the resonance is a hollow sad version when compared with the amped presentation of this track.
Amped: The resonance is amazing in this presentation as well the pluck of the standup bass is very distinct with a noticeable sound of the fingers sliding on the string.

Dynamic Test
I-Pod: This track is described as “a brute force test for speakers and amplifiers.” The i-pod presented an obscure presentation of this track. It had Hollow sounding drums, and fairly crisp cymbals but again a sad version when compared to the amped version.
Amped: In this version the presentation is much cleaner and dynamic, the cymbals jump out at you and the drums sound so realistic it feels like I have my head in hole of the bass drum. Excellent!

So in conclusion would I recommend the Biosciencegeek amp to i-pod owners. Well if you are even slightly serious about music you would be doing yourself an injustice by not purchasing one. I now define my portable music experience pre and post amp. I know that this is my experience with my tastes and equipment. However I’ am confident that the amount of difference experienced by other user’s will vary by the quality of their equipment, but it will definitely be for the better. This is my first review and would appreciate any constructive criticism/suggestions for improvement.

As far as the Biosciencegeek amp is concerned:
1.)I have found the build quality excellent!
Standard (DC jack, dual gain, auto power on/off, higher grade caps, a choice different mint tins, color of led and volume control knob.) Care and attention are evident in the build of this amp.
2.) The ability to customize the amp to your headphones is an appreciated and nice touch.
3.) Another invaluable component in any purchase is customer service. Sanjay Is an exemplar of what customer service is meant to be. He answered my questions in a timely and friendly manner. I cannot convey how excellent his customer service is.

Suggestions for improvement:
1.)Really not allot. I would however suggest some money-making suggestions to Sanjay. Offer the option of purchasing a different op-amp(s) at the time of purchase. “Rolling” op-amps would be fun for the serious geeks among us. Offer high quality interconnects perhaps one wired with silver wire, and one with copper. Again offered at the time of purchase.
2.)If you choose to purchase an amp and are interested in different op-amps be sure to let Sanjay know as I ‘am sure if he has it available an arrangement could be made to supply them at a reasonable cost.

Thank you

post #2 of 13
I had one and it's a nice little toy that works (i liked the LM chip with it). I gave mine away for Xmas.

In retrospect, a stripped mini^3 kit for the Same price is certainly possible. That's a performance to cost ratio that is hard to beat.

Nice review
post #3 of 13
Congrats on your first post.....Very well written review....!!
post #4 of 13
Sanjay's was one of my very first amps a few years ago, before I ventured into the worlds of Ray Samuels, Xin Feng, and a few others. Still use my little Cmoy and enjoy the sound. Great little unit with either my Ety4p or Triple Fis. He does, indeed, build a great little product and, like the reviewer, love the fact that he builds two levels of gain into the unit
post #5 of 13
Thread Starter 
thanks for your kind comments, i really appreciate them
post #6 of 13
I bought Biosciencegeek's Cmoy, based on a strong review online. When I got it, the sound was great but the little LED light didn't work and the outside tin was dented. I was going to let it go but eventually decided to stand up for myself. To my delight, BSG sent me a replacement and let me keep the original, which sounded great to begin with.

What's more, as I've rolled opamps, I've gotten really amazing sound - especially with the legendary opa627s. I had to buy an adapter to run single opamps, and between the adapter, the opamps and the extra battery I needed, I had to take off the lid. But the sound improvement of that Cmoy was breathtaking. I heard details that just blew my socks off.

For fun, I've ordered lots of different opamps, which I've had a veritable geekfest rolling. To my ears, the Opa2227 which came with the amp was boring. The LM4562 wasn't much different. For a few dollars more, I got BSG to send me an AD823 - which many have complained about - but I actually liked it. Because a lot of the newer opamps are SO-8s and SMD, I've had to buy Browndog adapters and solder them in myself (though Cimarron now sells some really cool premounted adapters for the lazy but curious). It was worth it.

This may not hold a candle to your 10,000 tube amp, but for $50, it's a great little unit. I highly recommend it.
post #7 of 13

Received mine today. Absolutely fantastic amp for the price. Was with high hopes already but it surpassed them. 

post #8 of 13

+1 for the BSG  cmoy.


I have had one for quite awhile now and it has been rock solid....great battery life too.


post #9 of 13

If you have a BSG amp already, I highly recommend asking him for the 18V upgrade option. It'll cost you the shipping and about 5-10$ in labour, but the sound is larger, a little more refined and overall a level up in musicality, IMHO.

the upgrade will certainly eat into the great battery life the 9V iterations of the amp have, but if you have some rechargeable 9v batteries to spare (or don't mind picking up a few - I got mine one sale for 6$ a piece and a charger for about 40$) it is a very worthwhile upgrade that will pay for itself overtime. I certainly wouldn't want to go back.

I also can't say enough about the service aspect of buying these amps. Great guy.

post #10 of 13

Enjoying my new BSG CMOY Amp (18 Volts). Bought wall transformer and a handful of OpAmps that I will eventually get around to rolling and comparing. Very nice quiet sound more dark than bright. Good bass and spacious sound. Using with iPod 160 Classic, FIIO Line-Out Cable, and assortment of headphones including: Etymotic HF5 and Grado SR-80 headphones (new earpads). 


Was thinking of replacing my stolen Ety ER-4s but now am thinking of staying with the HF5s IEMs, which do a very good job, and moving up to an open high-end home headphone like the Sennheiser HD 650 or 600 (as money and time allow). Also, I will eventually buy a portable high resolution digital player with line out, but want to let the market mature a bit more (and prices come down). 


PS...by the way, had a noise problem with the lower gain line output and had to return to Sanjay. In a period of just over a week he repaired it and, at my asking, changed the amp over to the Tiger tin. Great customer service.

Edited by tonyo123 - 6/1/15 at 4:18pm
post #11 of 13

i had Fiio E11 then sold it ... is the BSG amp will be an upgrade over it ? or must i go higher ? something like PD xm5 ?

post #12 of 13
 i had Fiio E11 then sold it ... is the BSG amp will be an upgrade over it ?

A definite upgrade. I used the E11 for about a week just to see how it compared. End result: not even close, BSG amp won hands down. my favourite part is the amp chip rolling capability. You will not be disappointed.

post #13 of 13
Originally Posted by ri-fi View Post

A definite upgrade. I used the E11 for about a week just to see how it compared. End result: not even close, BSG amp won hands down. my favourite part is the amp chip rolling capability. You will not be disappointed.

thanks for the reply ... really great to hear ^_^ considering that i have sold my E11 to upgrade!.... it will arrive in about 3 days or so ... i ordered the 18v version and the adapter and i will post my initial impressions when i put my hands on it .....
is it needs some burning in period ? and what is the battery life with your amp ?

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