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BSG Cmoy vs Tube Cmoy - Help me decide!

post #1 of 9
Thread Starter 

Hi all

I'm looking for a small amp to use exclusively for my DT 770 Pro-250s. My Dac is a Fiio E10, but I'd like a higher-quality amp. While portability is not a factor since this amp will be used at home only, I posted this in the portable section since both the amps I'm looking at are designed for on-the-go use. The first is a Biosciencegeek Cmoy, which I've used before, and know I will be satisfied with. So why wouldn't I go with that? Well, I saw this on the forums the other day:

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=200807704603#ht_4069wt_1041

It's just sooooooo attractive. Yes, I know it won't be of the caliber of a normal tube amp, but I don't need anything outlandish for my DT 770s. However, I can't audition this little guy, and sending it back to it's home in Australia would be too expensive to be worth it, so if I go for fred_fred's tube-based cmoy, there's no going back. And since I know I like the normal cmoy, either decision is likely permanent :P So my question is, should I go for the Tube Cmoy or the BSG Cmoy? I'd like to stay as close to the natural sound of the DT 770s as possible. DAC will still be a Fiio E10, source is Aiffs, Wavs, and lossy files on a Macbook. I listen to almost everything, but it's Alt Rock and EDM most of the time. And if you have any other recommendations in relatively the same price tier, let me know. Thanks for your help, I'm really freaking out about this decision (As most of my headphone purchases :P).

Cheers.

 

In MalVeauX we trust.


Edited by wes008 - 9/10/12 at 2:38pm
post #2 of 9

Call me skeptical - why is there a red or blue LED on the tube?  It has a JRC4556 opamp, so what does the tube really do in that design?  How do we know it's not just a tube stuck in the socket with an LED to light it up?  What's the LM317 for?  None of these parts are in the cmoy design, right?  It just doesn't smell right to me.

post #3 of 9
Thread Starter 
Quote:
Originally Posted by MeeHungLowe View Post

Call me skeptical - why is there a red or blue LED on the tube?  It has a JRC4556 opamp, so what does the tube really do in that design?  How do we know it's not just a tube stuck in the socket with an LED to light it up?  What's the LM317 for?  None of these parts are in the cmoy design, right?  It just doesn't smell right to me.

Omg, you might be right o_O Thanks for your insight. Anyone else?

Sent from my Galaxy Nexus.
In MalVeauX we trust.
post #4 of 9
Quote:
Originally Posted by MeeHungLowe View Post

Call me skeptical - why is there a red or blue LED on the tube?  It has a JRC4556 opamp, so what does the tube really do in that design?  How do we know it's not just a tube stuck in the socket with an LED to light it up?  What's the LM317 for?  None of these parts are in the cmoy design, right?  It just doesn't smell right to me.

 

The vacuum tube is probably for the voltage gain as in many "hybrid" designs, with the JRC4556 for output drive.  LM317 is just a voltage regulator, not that suspicious especially considering that this CMoy variant doesn't run off battery power.

 

 

 

To be honest, the E10 internal amp is probably better than most CMoys, though I guess if you listen really loud, you'll need some additional gain over that...

post #5 of 9
Quote:
Originally Posted by mikeaj View Post

 

The vacuum tube is probably for the voltage gain as in many "hybrid" designs, with the JRC4556 for output drive.  LM317 is just a voltage regulator, not that suspicious especially considering that this CMoy variant doesn't run off battery power.

 

 

 

To be honest, the E10 internal amp is probably better than most CMoys, though I guess if you listen really loud, you'll need some additional gain over that...

You are exactly right :-) the tube is the voltage amplifier, and the 4556 is configured as a unity gain current buffer,

 

the red and blue leds are not suspicious a lot of tube amps have leds under the tubes to give a nice glow, it also serves as an on off indicator, the tube heaters are not very bright on 12 volts and the led just cheers it all up  :-)

 

I did make a cmoy with a fake tube socket some time ago just for fun and I still have 2 left without cases, which I must get around to giving away

 

cheers

FRED

post #6 of 9
Thread Starter 
Quote:
Originally Posted by Fred_fred2004 View Post

Quote:
Originally Posted by mikeaj View Post

 

The vacuum tube is probably for the voltage gain as in many "hybrid" designs, with the JRC4556 for output drive.  LM317 is just a voltage regulator, not that suspicious especially considering that this CMoy variant doesn't run off battery power.

 

 

 

To be honest, the E10 internal amp is probably better than most CMoys, though I guess if you listen really loud, you'll need some additional gain over that...

You are exactly right :-) the tube is the voltage amplifier, and the 4556 is configured as a unity gain current buffer,

 

the red and blue leds are not suspicious a lot of tube amps have leds under the tubes to give a nice glow, it also serves as an on off indicator, the tube heaters are not very bright on 12 volts and the led just cheers it all up  :-)

 

I did make a cmoy with a fake tube socket some time ago just for fun and I still have 2 left without cases, which I must get around to giving away

 

cheers

FRED

Woah, Howard reaching right out! (I'm the guy who messaged you on eBay yesterday) Cool idea with the tubes as voltage regulation.

Sent from my Galaxy Nexus.
In MalVeauX we trust.
post #7 of 9
Thread Starter 
Quote:
Originally Posted by mikeaj View Post

To be honest, the E10 internal amp is probably better than most CMoys, though I guess if you listen really loud, you'll need some additional gain over that...
Ah, kk. Might just stick with that then... or buy a more expensive amp smily_headphones1.gif
Sent from my Galaxy Nexus.
In MalVeauX we trust.
post #8 of 9

I just ordered one of these off ebay to tide me over until I get my electronics bench set up and going. The seller described the improved components in it in detail, and even if it isn't that great, I can just fix it later when I get my oscilloscope and audio oscillator to fine tune it. :P

post #9 of 9
Quote:
Originally Posted by wes008 View Post

Woah, Howard reaching right out! (I'm the guy who messaged you on eBay yesterday) Cool idea with the tubes as voltage regulation.
Sent from my Galaxy Nexus.
In MalVeauX we trust.

Lol, I bet a lot of people message him... I did before. Got a nice reply, too. IMO, the CMOY would be really close to the E10 (with a bass boost option, dunno if you tried it with the already bassy DT770 or not, might be better off), so the Tube Hybrid amp would at least give you something new and different.

ClieOS wrote a review on a bunch of amps, Fred_fred2004's 3-channels CMOY was rated as one of the most enjoyable sub-$100 portable amps. I haven't seen an impressions review on the tube amps yet (the one you posted, or the desktop one), so I would be very interested to hear what you think if you went with that amp!
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