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need suggestion in upgrade of a Creek OBH-11 - Page 5

post #61 of 72

wut is funnay es that a pcb is copirited and akordengli seeeng the uregineal 2 kopi is of know uses since copirite protekshun is very strongly.

if u weir to seempli draw ur pwn pee sea bee from the schematek knowbodi cud sai boo! 


Not actual legal advice. Just general advice. 

post #62 of 72

This was not what I wanted. Enjoyed doing the OBH 21 SE

Maybe if the cost of  components compensating can entertain me for experienced home ...

Could do through the circuit posted above, but there may be errors in the connection of the transistors.

Edited by aneker - 10/14/13 at 8:50am
post #63 of 72

Well, you can check directly with Creek, that's how I got the schematic.

post #64 of 72

Sorry to revive an old thread, but it seems like a good place to post after lurking for a long time since it's related.


I finally upgraded my old Creek OBH-11 (rev 2.).  Caps are mostly Elna Silmic II, with a Nichicon for the power, some WIMA's and two orange drop's until I can figure out how to put my big film cans in the chassis.


Here's the problem:  After the upgrade, I don't have any bass.  Absolutely none.  What could have gone wrong?  Where do I look first?  I can put any of the old parts back in, one by one, if I have to, but I'd rather not go that route.  Suggestions?









post #65 of 72
Originally Posted by linesplice View Post

After the upgrade, I don't have any bass.  Absolutely none.


Those input caps you've got there don't look any bigger than 0.1 µF. The originals are 0.22 µF, and that's on the small side, IMHO. I'd like to see 0.47 to 1.0 µF here.


If you have more of those caps, you can simply solder-tack another one or two in parallel with the ones you already have. If that improves things, you've got your culprit.


Otherwise, much of my troubleshooting guide is just as relevant to this amp as it is for the amps discussed elsewhere on my site. Post all the relevant measurements if following the guide doesn't lead you right to the problem.

post #66 of 72

Thank you for the response!


Believe it or not, those are .233 caps, so similar to the original ones, but I changed one out for a Cornell Dubilier 940C (1uf) I had,and sure enough, the bass is back (on that side).  I suppose I should find a better cap, but I'm not sure what is better and still on the value spectrum when compared to diminishing returns for performance?  i.e. I'm not likely to buy $25/ea caps unless there is substantial improvement compared to $10/ea. capacitors.




- Is there any point to replacing all five of the small caps?  If so, any recommendations make/model?  I believe they are all 1000pf.  



The guide is great, by the way.  Thanks for posting.

post #67 of 72
post #68 of 72
Originally Posted by linesplice View Post

Believe it or not, those are .233 caps


.233 what? Picofarads? Megafarads? Always give units.


.233 is also probably the wrong value, since that is not one of the common capacitor values. You could have one custom-made, but off the shelf? No.


It's also not likely to be a capacitance value code, since that would mean "23" for the significant digits and "3" encoding the decimal position, but again, "23" is not a typical 2-significant-digit capacitor value. "22" is, which means the code might be "223", which in typical capacitor numbering systems means 0.022µF, in which case no wonder your bass is totally rolled off, since your caps are 10x too small for the intended purpose.


Furthermore, when we say "orange drop" here, we mean Vishay Sprague model 715P or 716p capacitors (or their CDE variants), which are about an inch and a quarter long for 0.22µF at 200V tolerance, so either those aren't what we call "orange drops" or they're not 0.22µF. It's a bit hard to tell scale from the pics, but it's much more plausible that those are 0.022µF 200V caps, which would be ¾" long.


  Is there any point to replacing all five of the small caps?


Probably not. They all look like film types to me, which means Creek has already avoided most of the mines in the capacitor field, even if they're only so-so quality.  They're still miles ahead of ceramics or electrolytics for audio signal path applications.

post #69 of 72

Tangent, I think you nailed it.  Maybe they are 2200pf!


post #70 of 72

Yes, that appears to be the case. So, 100× too small.

post #71 of 72

Well, here is the finished product (for now).  It was an interesting experiment.  30 hours of break-in and the sound is slightly better than where it started prior to replacing the capacitors, and in some cases I still have a preference for what is coming out of my computer headphone jack to the little Creek amp.  I'll have to try some more demanding headphones to see if it matters, since the AKG K712 pro's I generally gravitate to are fairly easy to drive.


What else could be done to really have a chance at improving the sound?  Should I have used a larger cap on C12 (100uf 35v)?  Replace the four little clear caps (C106, etc.) with something else?  Try to go larger on the power supply cap (c11)?  Replacement of resistors?  





post #72 of 72

Also, are there any suggestions on how I would increase the output power while retaining the same design?  For it's size, there are plenty of modern portable units which can push a dozen times more power in a smaller form factor.  Any thoughts?

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