[Kouzelna]

 
(Just a quickie posting on my impressions after a month of usage).  
 
 
I am so wildly impressed with the awesome - no, stunning - results I've had using BSG's cMOY amp with my Etymotic ER-4S (the ER-4P with the attached "S" resistance cable).
 
I absolutely could not - could never - recommend a better amp with this IEM.  If you own and love your ER-4, I HIGHLY URGE YOU to get a BSG cMOY like mine (more on my specifications below, be sure you read it).
 
 
I've owned the ER-4P since 2004.  It recently had a complete overhaul by Etymotic when I accidentally, gasp, snipped the wire.  It was like I had accidently dropped a knife and killed my dog; my neighbors said I was walking around literally traumatized.  I'm sure you guys understand.  
 
Anyway, tangent story here, but Etymotic came through and fixed it up for $50 lousy bucks plus $6 shipping.  While they had it, (they must be fanatics like all of us), they not only replaced the wire, but also replaced both transducers as they found they were cracked, then replaced some other guts in there, then replaced the housing for the transducers, then replaced the entire wire assembly with a black, heavier insulated one, so I no longer had the braided wire with the 80s "red/blue/green" look that I always thought was kinda weird.  In essence, I think, I got a brand new pair with numbered transducers.  Pretty hot!  I love this company!
 
 
Back to my review, in nearly 7 years I've never been more in love with a headphone than the ER-4.  Anyway, I've used it with a number of amps and sources, but nothing EVER compared with the sound that's opened up on these little guys with the BSG cMOY.  (For an awesome tube sound with the ER-4, nothing compares with the Wheatfield Starving Student from Whiplash Audio.  I have a Glow Audio One which I love with it, but it presents a very accurate "live" sound, whereas the Wheatfield just does crazy magic with the ER-4 and seems matched with it, as the BSG).
 
Funny enough, the BSG I have was designed specifically for a 600-ohm Beyerdynamic DT880/600.  Whatever, it works absolute wonders with my ER-4S (100 ohm total).  So take note of that.  If I was to buy one for a friend with an ER-4, I would have it matched accordingly, NOT matched to the ER-4.
 
 
How does it affect the sound of the ER-4S?
 
For those of you intimately familiar with the ER-4 sound, it does the impossible we've all been waiting for:  it deepens the bass and increases its impact; it VASTLY broadens its soundstage, but L/R and Front/Back; it creates a literal "3D" effect that seems to extend the sound beyond your head (a first for me, with the ER-4); and if all that isn't enough, it improves the ER-4's already awesome midrange by adding body to it.  All this, without sacrificing any of the spectrum clarity and smoothness you already love and admire in the ER-4.  And all of it is presented with a dead-silent, vacuum like silence in the backdrop.  It's as if the sound comes out of pure nothing.  Just awesome.  (I use the BSG with a quality DC wall wart; haven't tried it with the 9v).
 
Please note, none of this sounds artificial in any way.  I don't believe the BSG "adds" or changes any sound in the ER-4.  I think it is the first amp I have ever heard that finally brings out the true and real potential of the ER-4 IEM.  Finally, it's as if it's been set free to breathe fully, and let it's full potential out.  And the results are stunning.
 
Honestly, I could not recommend this setup more.  My source is a humble iPod Nano 4th Gen, and I am getting sound out of these headphones that just make me cry.  I am listening to it more often these days than even my K701 / Glow Audio One setup, that costs 5 times as much.  
 
If you own the ER-4, SURF RIGHT NOW to get a BSG cMOY from eBay.  http://myworld.ebay.com/biosciencegeek/
 
(I would suggest setup for the 600-Ohm Beyerdynamic DT880/600).
 
Post your impressions if you get the setup.
 

 

[ricksome]

I use the same set up as you do. BSG is the bomb. Every word you write is true

 

[AlexRoma]

Kouzelna, Great review ! Nice job.. A bit too emotional, but informative enough to make sense what the amp is up to.
 
I've studied the seller's product description on ebay, but still could not find the answer on this question :
 
Is the amp a portable device (and if so, how long can in feed your ER-4 from stock battery), or it needs a constant power connection ?
 
Looks very nice and solid for the price...

 

[ElcomeSoft]

Seems neat. A shame that he's not UK based because the delivery and customs charges would rip me a new one if I ordered. For example purposes only, if Customs didn't get around to charging me the earth for the priviledge, it would cost me about £42 and the Fiio E7 (something I've been recently reading up on) would set me back £49.
 
What are the dimensions and weight of this device? Is it portable?
 
Wait... let me scribble up some questions and just ask the seller myself

 

[Kouzelna]

Hey guys, yes, the amp is extremely portable.  It comes in a candy tin, very small, as it is an Altoids tin.  It is also extremely lightweight.  The tin is easily dented, but it is tough and is not going to break as it's metal.
 
Yes, it runs from a 9v battery.  I use Duracels in it, and I ran out my iPod Nano (10 hours) before a single battery went out while running my ER-4S on a plane.  Awesome trip!
 
It also works great with the AC plug, of course.

 

[imackler]

This sounds really exciting! Can anyone compare any other amps with it?

 

[ricksome]

Better than many portable amps that cost up to $200.00 This blows off their battery covers!!!!!!!

 

[129207]

Quote:

Better than many portable amps that cost up to $200.00 This blows off their battery covers!!!!!!!

 
 
[size=medium]

Oh come on guys. It's a CMOY. A good one!  But let's not exaggerate and don't go screaming it's the next best thing since sliced bread. 

 I've been recommending this CMOY for anyone looking for a cheap, yet decent portable amp. And that's exactely what it is. 
 
If you like your Ety's through the Biosciencegeek, wait 'till you hear them through the Arrow or TTVJ Portable. 
​

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[Kouzelna]

Hi, can you either PM me or list here where exactly you got it?  I lost my contact info for the BSG guy, Sanjay, and want to order another one.  

 

[ricksome]

Go on ebay home page and hit the advance search button. Click search by seller. Put in the name biosciencegeek. His listing will come up.

 

[Kouzelna]

Thanks ricksome, it worked.  But I also have his email address, and we've been talking about my ordering a new amp from him.    Yeah!  His stuff is the best, the sleepers of the HiFi world!
 
I don't know, Negakino, I think it may be a whole heck of a lot better than sliced bread! Have you heard it?  It is quite an amp, at quite a price.  What are the other amps you mentioned?  I'm curious, and am not familiar with them.  But for Heaven's sakes, you can buy SEVEN BSG amps for the price of one TTVJ, and SIX BSG amps for the price of one Arrow.  
 
So... the point we're making here, is pretty valid!  

 

[129207]

Quote:

 But for Heaven's sakes, you can buy SEVEN BSG amps for the price of one TTVJ, and SIX BSG amps for the price of one Arrow.  
 
 

Hahaha I see where you're coming from and I fully agree it's a good value. It doesn't amplify my more demanding headphones (DT880, HD580) properly though. The Arrow doesn't even break a sweat. The Arrow has 3 crossfeed settings, 3 bassboost options, 3 gain modes, 3 impedances modes, two headphone outs, an incredibly small form factor and an automatic on/off function. The battery runs for 30+ hours and it's build with almost autistic quality control. Seriously, $300 is absolutely reasonable. I rather have one amazing portable amplifier than 6 Cmoys that end up in the drawer.  
 
Let's agree on the BSG being the best portable amp under $80? 
 

 

[Kouzelna]

Ah, $80 sounds a little limited.  I had a NuForce for $110 and an Airhead at $150, and the BSG was far better than both.  And mine was built for the 600-ohm DT880, and powers it and my old K701 just fine.
 
Have you tried running the BSG with a power adapter?  It does a better job on larger headphones, but will still do the trick with a new battery, to my knowledge.  
 
The Arrow sounds great, though.  Again... at $300!

 

[Albinoni]

I'm not here to bash BSG's CMOY Amp no not at all and I congratulate him on what he builds and I am sure it sounds very good too, but some question's I would like to ask:
 
1. Why does he just use the OPA2227 opamp when there are so many opamps out there, I have found one the best sounding opamps to be the JRC45556 Opamp and also AD (analog devices opamps).
 
2. My CMOYs are all built by Fred Fred (Howard) here in Perth Australia and I am sure quite a few here probably have bought amps off him and his amps are very very nice sounding, and brilliant workmanship and very
   clean too.  But what I like is that he experiments with different type Opamps as well, I own about 7 of his amps and been more than happy with them. What I like about Fred Fred is that he uses JRC45556, OPA2227
   LM4562, OPA2132, and dual chip LF4562 and LM6171 opamps.  But like I said also what I love about his amps is that their nicely and neatly finished, i.e very clean.
 
3, I would be willing to still buy and try BSG's amp without a doubt and would be worth a try.
 
Btw how does it compare to BassBoost Cmoy V2.03

 

[Kouzelna]

Albinoni,
 
you missed the point a little:  Sanjay builds the amp according to your needs.  He has a variety of parts available, and will tune the amp according to your headphones, or your desires with OpAmps etc.