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Switch on the Onix OA21S

Ivelin--Just seeing your message, AFTER I hooked up the switch. Thankfully, everything seems to be working as it should. Thanks for your help.
 
It hasn't replaced anything but simply added to the ever increasing number of black boxes I own (although the Onix is arguably the best looking of the bunch). I'm using it in my home office, which is a luxury to say the least. So keep in mind that, as far as I can tell, this one has not been serviced. Or, if it has, it's been awhile. (The numerical code on top of the smoothing caps, for example, is 9404, which may be a date code [April 1994?]). Anyway, overall the thing sounds great. True, the bass is a little soft and mushy. But, overall, it is very involving, lovely presentation, nice PRAT, and so on. It lacks the authority and "slam" of my Naim 202/hicap/250 but the comparison is hardly fair.

To me, it raises the question why, apart from aesthetics, some of us went chasing after a new Onix when Tony Brady (one of the original designers of Onix) is sitting over at Exposure producing equipment that, I suspect, sounds as good or better. Having said that, I have not actually heard any of Tony's Exposure designs but lots of people seem to like what he has been doing.
 
PS: I haven't had a chance to try the phono stage (and that may be awhile), which (I think) it has. Also is dead quiet. No audible hiss even when you put your ear right to the speaker.
 
No hiss is a good sign. You could check with a multimeter on the speaker terminals for DC voltage; if it is well under 50mV I wouldn't think it needs anything done to it. I think 9404 is week 4 of year 94.
I've never heard a 202/hicap/250 but I could imagine that this Naim combo is in a different league. I wonder how my oa601 compares to the nap250?!
I found out too late about Exposure, otherwise probably I would have gotten some of the Exposure amps. Anyway something to think about.
 
Checked the DC offset. 48.3mv left channel and 10.4 right channel. So barely under 50mv in the left channel. Should I worry?
 
Thanks for the link Ivelin. I'm sure someone here knows what and whether do anything about the DC offset. I'll ask. A question about something more straightforward: what sort of tool is recommended to trim spindle on the powerswitch. It sticks out quite a bit further than the one it replaced. I probably should have trimmed it before I installed it, but I wasn't quite sure how short it should be.
 
Is it plastic? You could try with a fine hacksaw and then use a file to smooth out any edges. Maybe measure how long the old one was in order to establish how much to cut off.
 
PXL-20210217-205230488.jpg
looks like the switch on this pic is too close to the transformer that blue mains wire is very close to the transformer secondary windings !
 
looks like the switch on this pic is too close to the transformer that blue mains wire is very close to the transformer secondary windings !
The switch has to be there -- that's where the hole is in the faceplate, and how the previous one was oriented. And it looks like the arrangement inside @misterc6's in his sale photo:

IMG-0778.jpg


What do you foresee happening with the blue wire? There appears to be thick heat shrink over the connection, and the transformer is wrapped.
 
looks like the switch on this pic is too close to the transformer that blue mains wire is very close to the transformer secondary windings !

Yes, it's a little bit too close but the wires are insulated. It is annoying me a tiny bit cause I can see how it could have been done with more room around the switches and the trafo, but maybe back then it was not that obvious. Checking images on Google suggests that most oa21s are built this way; this layout of the innards is allowing the symmetry of the three knobs on the outside too.
 
A few more questions (not all of which are DIY questions).

(1) For those familiar with the inside of their Onix OA21, does the LED light sit in a LED "holder" or does it just sit near the hole without a holder. Mine is in the latter category. By "holder" I'm thinking of something like this.

(2) Setting aside what anyone thinks of their sonic attributes (or lack thereof) does anybody see any issues with driving Linn Saras with an Onix OA21S. In particular, do you think they would be too difficult for a 21S to drive. FWIW, mine are the versions with white woofers.

(3) My 21S appears to have a removable phono board (not positive about that but it looks removable). If I'm not using a turntable with the amp, would there be any sonic advantages to pulling the phono board?
 
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1. On my amp the led is in a rubbery sleeve.
2. Cannot comment.
3. Mine is removable, it is above the main pcb; it has a bolt holding at one end and on the other it has some multipin socket (brown) which is almost as wide as the board itself and just pulls out. I had it off and didn't notice any sonic difference. There is something about phono board and SOAP (external power supply) but I don't know the details.
 
Thanks Ivelin. Having had the Saras hooked up for several hours now, I think I've answered my own question. Sounds fabulous and the the amp doesn't sound like it is struggling at all. The Onix case [top and bottom] is completely cool. In the past, when I've used the CB 250 to drive Saras, the 250 would get noticeably warm in a hurry. I suppose it is possible that the heatsink compound in the ONIX has dried out and heat is not being effectively transferred to the case. But, again, the amp doesn't sound like it is struggling at all. Completely composed and effortless. Sounds great.
 
That's a good news! :D
The Onix has the transistors on a thick aluminium piece bolted to the bottom of the case. You could try touching under the case where the bolts' heads are and see if it is any warmer. I am not using mine and cannot comment about how warm it gets, from memory the top was indeed cool. I am using an onix power amp and it does get warmer at the bottom.

So what are you going to do with the nap250 then? ;)
 


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