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Oatley K272A Thoughts? Comments? Etc?

post #1 of 21
10/25/11 at 9:45pm
Thread Starter 

Accidentally posted this under DIY rules...oops...sorry.

 

I was just checking out the Oatley K272A:

http://secure.oatleyelectronics.com//product_info.php?cPath=100_104&products_id=885

 

Anyone have any experience?

It looks like a really simple kit and I thought it might be fun.

 

How does it sound? How big is it? What case did you put it in? How powerful is it?

 

Pictures?

 

I guess I'm asking a lot, but I'm pretty excited, this thing looks like fun!

 

Thanks!

 

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post #2 of 21
10/25/11 at 10:17pm
http://www.head-fi.org/t/453425/tube-headphone-amp-kit-for-25

Here you go. From what I skimmed, it's supposedly a fine amp, but not portable because the tubes ring like "pitchforks from hell."

It looks very fun to build; if I wasn't already to build an O2 I'd be all over this. Have fun! smily_headphones1.gif
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post #3 of 21
10/25/11 at 10:32pm
Thread Starter 

Great Thanks!

 

I'll probably do this in a few weeks to months, I'll post.

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post #4 of 21
10/25/11 at 10:34pm
Yeah, maybe during the winter time I'll probably tackle this amp too.
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post #5 of 21
10/25/11 at 11:35pm

This is what I came up with

 

P1030957 (Small).JPGP1030953 (Small).JPG

P1030949 (Small).JPGP1030951 (Small).JPG

P1030956 (Small).JPGP1030954 (Small).JPG

 

cheers

FRED

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post #6 of 21
10/25/11 at 11:43pm
Thread Starter 

Awesome box!

 

How's it sound? Does it have that warm, tubey sound? Powerful?

 

You did what I was planning, skipping the transpots and going to a stereo pot.

 

I'm considering since it isn't particularly portable somehow running off a power supply. Since the power circuit requires 7+V, could the other, 3V circuit handle the same and just power them in parallel?

 

Thanks.

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post #7 of 21
10/26/11 at 12:07am

The tin I found at an op shop :-)

 

The amp sounds good, and yes a definate warm tubey sound, its very sensitive to outside interference

 

you could use an external power supply but it would need to be very quiet, to be honest the batteries last for ages so its not a big issue

 

cheers

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post #8 of 21
10/27/11 at 1:04pm
Thread Starter 

Fred

I can't seem to find the info anywhere. What are the dimensions of the board? What I'm really asking, how big of a case will I need?

 

 

Any other neat, inexpensive builds for cool little amps/DACs?

 

Thanks!

Scott

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post #9 of 21
10/27/11 at 4:37pm

Hi roughly 138mm X 65mm so not very big

 

cheers

Fred

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post #10 of 21
10/27/11 at 4:43pm
Thread Starter 

Thanks a ton!

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post #11 of 21
11/1/11 at 5:42pm

I didn't think much of it when I built mine. Underpowered with seriously ringy tubes. Not something I would use on a day-to-day basis.I would recommend something like a CMoy for a cheap, easy build.

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post #12 of 21
11/1/11 at 9:27pm
Thread Starter 

I'd heard that. I have a CMOY, I'm rather ashamed that I bought one fully complete. Anyway, I think I'll give it a try. If it's no good, I'll leave it with my things at work, even underpowered beats no amp.

 

I have some ideas about dampening the tubes and whatnot. Did you experiment with that at all LingLing?

 

Thanks for the input!

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post #13 of 21
11/2/11 at 4:52pm

Oops, I just replied to your thread under the rules section. You can go read what I put there, right?

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post #14 of 21
11/2/11 at 5:42pm
Thread Starter 

POSTED BY JOE:

This was my first headamp, and my first proper DIY project. It's incredibly simple to build and ridiculously cheap, but does have a few caveats. Advantages are that it sounds damn good for what you pay, but the disadvantages are that it can only be run off batteries unless you have/build a crazy quiet linear PSU (which would probably cost as much/more than the whole amp), the tubes are incredibly microphonic (they ring quite loudly unless well damped, and a bit even then) and the tubes are also pretty sensitive to noise (so make sure you put the PCB in a grounded metal enclosure).

 

I'm afraid I can't give any pictures or measurements because I'm away from my K272A right now, but I put it in an old cigarette box (a pretty big one) and was very happy with it for about eight months before it was superceded by my current amp. Essentially, if you're planning this as your first DIY experience go for it. Oatley were incredibly helpful with arrangements even though I'm in the UK, and even though I got mine picked up by a family member their postage is very reasonable worldwide.

 

(Also this should probably be in the main DIY section rather than the rules section. In fact, why isn't the rules section just completely locked anyway?)

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

 

Joe, I appreciate the input. I have some ideas about dampening the tubes. I'm building mine in cigar boxes which I plan on lining with foil to prevent noise, then lining with foam to dampen vibration. I don't have an adequate metal box, so I'm hoping that will work out all right.

 

Thanks for the input!

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post #15 of 21
11/2/11 at 9:47pm
Thread Starter 

Fred, I've read elsewhere that the transpots are imperative because the two tubes are seldom identical. Did you have any problems with different left/right volume levels using just a single pot?

Thanks!

Scott

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