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A Very Compact Hybrid Amp - Page 128

post #1906 of 2213
Quote:
Originally Posted by suicidal_orange View Post
While on the subject of wallwarts is there anything special I should be looking for? Some are switching while others say nothing (is this just unnecessary marketing?) I'm in the UK so need a 230v model, none of those pictured are. 24v AC and >750ma with a 2.5mm pin - is there anything else I need to look out for?
Switching won't work, as it would be DC - Don't use 24VDC under any circumstances!

You want to make sure it IS rated for 24VAC GREATER THAN 660 mA.

I know higher is psec'd but I've run plenty with 3/5 of an amp. It's pretty straightforward to graft on a 2.5mm connector cable 9I find actually wiring the plugs to be a pain though). Or I could send you a 2.1mm jack if you can find a proper wall wart with that connector...
post #1907 of 2213
Well we my CTH #11 is up and running. I can't seem to find a 100uF/100V cap to finish up CTH #12..anyone got a spare they can send me, save me from putting in an order?
post #1908 of 2213
I'm placing a Mouser order tomorrow. Get me a part #, and I'll send it
when my order comes in.
post #1909 of 2213
Quote:
Originally Posted by funch View Post
I'm placing a Mouser order tomorrow. Get me a part #, and I'll send it
when my order comes in.
Sweet..will send you a PM. Thanks a lot for the offer!

Edit: Oh and the completed CTH.
post #1910 of 2213
Quote:
Originally Posted by Forte View Post
DSE used to sell this AC Adaptor 24Vac 1.5A (M9635) | Dick Smith Online Store, but appears it to be discontinued, you may get lucky though if you try your local store(There are a few stores in Victoria that still show stock), I managed to pick up one cheap as clearance stock a few months back, came with 1/2 a dozen different interchangeable connectors.
I was lucky enough to score one of these transformers, but have a question:

the ends are indeed interchangeable and can be fitted so that the polarity is either positive or negative. Which polarity should I use?

(Already PM'd Wiatrob and Forte about this: but am so keen to hear the CTH, I thought I'd post here also)

Cheers!
post #1911 of 2213
Got the answer: thanks Jon!
post #1912 of 2213
Well, never mind my PM, seems you figured it out...
post #1913 of 2213
Quote:
Originally Posted by Duckman View Post
I was lucky enough to score one of these <snip>
(Already PM'd Wiatrob and Forte about this: but am so keen to hear the CTH, <snip>
As you have your answer now are your hearing it yet?
post #1914 of 2213
Just in case some are subscribed to this thread, please see my latest post to CTH tweak thread for findings WRT coupling caps, 6F8Gs & CTH/e12 latch sensitivity.
post #1915 of 2213
Well I finally got a wallwart (24VAC 1A) and plugged in my CTH. I hear a clicking and turn it off after maybe 5 seconds - the last cap I attached (C10P) was backwards. Swapped it around, turned it in again and let out some smoke

I've looked (and smelt) it over but can't see anything thats obviously cooked. All the other caps are correct, and the diodes are the right way round but I can't see to read the numbers. I didn't rush the build so they should be correct, but if I made one mistake maybe there's another The only other thing I noticed was that the first time the LED was green and the second red if that helps...

Do caps die that quickly? What else would have died if this cap did? The smoke didn't seem to be coming from the cap, but was from that end of the board. I was stood back by the plug incase you were wondering, to be quicker than 5 seconds if needed without risking being covered in blown cap (never seen one blow, but it doesn't sound fun)

Thanks for any help
post #1916 of 2213
It is a shame & mystery why member sachu is presently banned, because he'd have post diag steps by now. He has the most experience with this. Oh, well, the community suffers.

C10P is the main cap in the HV section. It is hard to say what has been damaged. I've had smoke rise from components and try as I might can see which ones. Usually smoked resistors are obvious, blown/vented caps really stink & you see residue, but damaged transistors are harder to spot. They usually have to really be burned to show the damage.

I'd first carefully review the parts & orientations against the many files on CavalliAudio. Once you are sure all the right parts are in the right spots & correct orientation you can begin trying to crawl through the build (from PS in forward). You should at least check that C10P that was reversed hasn't vented/raised its top. And google for checking caps - using ohmmeter then reversing leads on the cap may tell you something.
post #1917 of 2213
Quote:
Originally Posted by acvtre View Post
What would you say about the CTH plus senn hd600, does anybody own this rig? I'm going to buy 'em, since they are more neutral than the hd650.
BTW, now that I've HD650s I can say CTH drives them very well.
Only owning HD650s for 16hrs & doing a little tube rolling, 6922 PQ & 8416 is good w/them. But I've a bunch of tubes to try & I think there are better matches.
post #1918 of 2213
I've been ordering parts for a CTH but have gotten stuck on the LM2595 regulator. Neither mouser nor digikey has them in stock and I can't find a place to get a sample for one either. Anyone know where to try? I'm also missing a 220uH 0.8A inductor which I would really like to get from the same place to avoid more shipping costs if possible.
post #1919 of 2213
post #1920 of 2213
I located the source of the smoke Q1P now has a nice burn hole in the flat side. When I turned it on to find this out the LED went green after about 20 seconds, and the smoke stopped. Turned it off, replaced Q1P with a fresh one plugged it back in and - nothing. No smoke, and a 0v reading between SG and OG...

C10P looks to be dead as the top has noticeably raised, so I'll have to order a replacement but I'm worried as to why the whole amp appears to have died. Any ideas? I'll order a new cap today, but don't really want to be wasting money on postage.
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