Info on Creek OBH-21 and OBH-21 SE amps.
Feb 7, 2003 at 1:23 AM Thread Starter Post #1 of 90

Alex Altorfer

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Hello fellow headfiers!

The following info has just been posted at Creekaudio's website:

Quote:


CREEK AUDIO ANNOUNCES NEW PRODUCT RELEASESÊ
OBH21/OBH21SE HEADPHONE AMPLIFIER

The OBH21 is a miniature audio amplifier specifically designed to drive two pairs of low to medium impedance headphones from a line level source.

The OBH21SE is a high-end version using more expensive components and power supply.

DonÕt be fooled by the size - Creek has left nothing to chance when it comes to performance

The OBH21 and OBH21SE are compatible with any source at line level. For example, an average output level CD player can be connected directly to the input of the OBH21/21SE, just as it could be used in conjunction with a stand-alone pre-amplifier or integrated amplifier which doesnÕt have a headphone output.

The OBH21 is not designed to be connected to the high-level speaker output of an integrated or power amplifier. Output level is controlled by the high quality volume control on the front panel.

The OBH21 and OBH21SE are the first of the new style OBH products to be released. With slightly longer casing, these models feature a stylish aluminium front panel in a silver finish.


http://www.creekaudio.co.uk/news/index.asp

The following questions remain unanswered, though I've just e-mailed Creek with an inquiry. (I'll post any new data as soon as arrives in my mailbox):

1. What are all the basic differences between the OBH-11 SE and the OBH-21 SE?

2. Does the OBH-21 SE contain better capacitors than its predecessor the OBH-11 SE?

3. Does the OBH-21 standard (non SE) edition of this amp contain only one headphone jack like the standard OBH-11? (see 'EDIT' comments below).

4. Will the OBH-11 SE be discontinued in favor of the OBH-21 SE?

If anyone has auditioned any of those new devices, a review would be greatly appreciated!

Cheers,
Alex Altorfer
smily_headphones1.gif


Edit: Well, by reading the text quoted above more carefully I realized one can infer that the standard version OBH-21 also drives two pairs of headphones. Sorry about that. My guess is that the OBH-21 and the OBH-21 SE look absolutely identical externally speaking. Perhaps the standard edition OBH-21 is powered by a walwart power supply, though I'm not yet sure about this.

 
Feb 10, 2003 at 2:40 AM Post #5 of 90
Sandro,
Thanks for the link. It actually states the OBH-11/11 SE has been discontinued. What we need now is someone to post a comparative review of the old models vs. the new ones.
Cheers,
Alex Altorfer
smily_headphones1.gif
 
Feb 10, 2003 at 5:11 AM Post #6 of 90
AudioAdvisor has recently dropped the price on the OBH-11, a good sign that it's discontinued, too. (The link you gave just talks about the SE version.)
 
Feb 12, 2003 at 10:24 PM Post #7 of 90
Hello Again Everyone!
smily_headphones1.gif


Jacki Pugh from Creek Audio has been very kind as she's just sent me fresh information on the new OBH-21 series amplifiers. I hereby quote her e-mail in full:

Quote:

Thank you for your email.

I have outlined the major differences for you between the OBH21 and its
predecessor - the OBH11:

Cosmetic change Ð casing is now longer Ð Dimensions: 100 x 150 x 60 (WxDxH)

Has a solid 5mm anodised aluminium front panel in brushed silver and
printed black

Incorporates new and more advanced circuitry

Uses professional standard operational amplifiers which can drive
headphones directly

OBH11 & 11SE used discrete transistor technology Ð OBH21 & 21SE use high
grade integrated circuits

Both the standard and SE versions of the OBH21 accommodate 2 pairs of
headphone sockets

The OBH21 & 21SE uses internally advanced circuitry is to split the
power supply from a single positive to a split positive/negative supply
which allows circuits to be DC coupled to eliminate capacitors on the SE
version

The ability of the OBH21 & 21SE to drive different types and impedances
of headphones is greater than its predecessor

Perhaps the greatest difference lies in the fact that the OBH21 & 21SE
is favourable to all makes of headphones. The OBH11 & 11SE showed
noticeable differences between different headphones, favouring those it
suited and making those it did not suit less attractive. This is not the
case with the new models.

The OBH-11 and OBH-11SE are discontinued now.

In terms of pricing, please contact your local Creek distributor -
details appear on the Creek web site.

Regards
Jacki

Creek Audio Ltd
www.creekaudio.co.uk


Please guys I'm still very much of a newbie so I'd like you all to comment on this and what it all represents. I suppose the use of opamps as opposed to a discrete circuit plus major powersupply modifications should really change the way these amps sound compared to their predecessors. Do you all agree? What sonic changes should we expect? Suppose one found it necessary, how easier (or more difficult) would it be to upgrade these new amp's components?

Cheers,
Alex Altorfer
smily_headphones1.gif
 
Feb 12, 2003 at 11:06 PM Post #8 of 90
I'm confused too. I thought that all discrete circuitry designs are better than opamp based designs? Providing of course the all discrete design uses high grade parts. Am I missing something here?
 
Feb 14, 2003 at 2:55 AM Post #9 of 90
Sean H,

According to some reviewers on this forum, the parts under the OBH-11s' bonnets weren't exactly high grade (e.g.: Samwha capacitors). Even if discreet designs are generally better (are they really?), perhaps the new opamp based architecture will produce better results at a smaller cost to the manufacturer in this particular case. Of course, this is all speculation of mine here. Please someone correct me if I'm wrong.

Cheers,
Alex Altorfer
smily_headphones1.gif
 
Feb 22, 2003 at 2:25 AM Post #10 of 90
One more thing that is unclear to me: Does the OBH-21 SE use the OBH-2 powersupply like the OBH-11 SE? Jacki Pugh's letter suggests otherwise:

Quote:

The OBH21 & 21SE uses internally advanced circuitry is to split the
power supply from a single positive to a split positive/negative supply
which allows circuits to be DC coupled to eliminate capacitors on the SE
version


However, I've read on an earlier post that the OBH-21 SE was seen on display at a fair connected to an OBH-2 powersupply. Also, Jacki says it's "internally advanced circuitry" which may mean no changes as far as external PSUs go. I will e-mail Creek Audio asking them this and post what I find out. Meanwhile, if any of you already know the answer please enlighten us.

Cheers,
Alex Altorfer
smily_headphones1.gif


obh2.jpg
 
Feb 22, 2003 at 4:29 AM Post #11 of 90
This "internally advanced circuitry" sounds like obfuscatory marketroid-speak for "rail splitter". Look at the META42 or CMoy headphone amp schematics for typical implementations of this straightforward concept.

All you require for this to work is a power supply that's isolated from the power line, so that your virtual ground can "float" to the same potential as whatever "real" grounds are used by the rest of your listening system. Either the OBH-1 or the OBH-2 power supplies would work with a rail splitter.

Internally advanced...feh. I'll believe it when I see the schematic.
smily_headphones1.gif
 
Feb 26, 2003 at 11:27 PM Post #12 of 90
Well so far these new amps are to me a big enigma. According to Moonwalker, a magazine in the Czech Republic has published an unfavorable review, indicating that the new Creek amps do not show significant sonic improvements over their predecessors and may not even be Class A operated; However, Duncan has just purchased the OBH-21 SE and will be posting a review very soon. Although it's still burning in he says he's impressed by it. Let's wait and see...

Here's the link to his thread:

http://www4.head-fi.org/forums/showt...threadid=27754

Cheers,
Alex Altorfer
smily_headphones1.gif
 
Feb 27, 2003 at 3:23 AM Post #13 of 90
Tangent,

Thank you for the info on the "rail splitter". Please let us know when you get to see the OBH-21 SE's schematics and reveal your thoughts about it. I understand your opinion is quite authoritative on this subject.

Thanks,
Alex Altorfer
smily_headphones1.gif
 
Feb 27, 2003 at 12:33 PM Post #15 of 90
Thank you radrd for the link. There I have found additional info, such as the following specs:

Quote:

Specifications
OBH-21SE Headphone Amplifier

*Output power: >10 mW into 30-300 ohm loads
*Headphone impedance: 30-300 ohms
*THD: <0.005% at 1 kHz
*Signal-to-noise ratio: >70 dB
*Power consumption: <8 VA
*Power supply: 24 V DC, 250 mA
*Dimensions (excluding power supply): 4" wide, 7.4" deep, 2.4" high
*Weight (excluding power supply): 20 oz.


Once again Creek has not provided any frequency response data...

-----------------------------------------------------------------

And the following pics of both front and back panels:

CROBH21SE_000.jpg


CROBH21SE_001.jpg


As we can see, it looks identical to the Creek OBH-11 SE except for the slightly longer casing and 'silver' brushed aluminum front panel finish.

Cheers,
Alex Altorfer
smily_headphones1.gif
 

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