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Post by Deleted on Oct 15, 2015 21:07:48 GMT
Nice work Chris !
That reminds me that I should get a few more heatsinks to bolt onto the low profile ones I am using with this build, now that summer isn't far away. They have to be low profile types due to being in a 1U rack case. It's just that the new modules sound so good now with 68pF instead of 100pF at the input, that I don't want to stop using them!
Kind Regards
Alex
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jc
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Post by jc on Oct 18, 2015 17:43:27 GMT
Hi Alex, Is there any mileage in trying 68pf on the power amp as well? I was having another bash at the ESD1 diodes for the power amp boards today, went under board this time for a variation on the theme.  |
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Post by Deleted on Oct 18, 2015 20:29:27 GMT
Hi Chris There is only one way to find out, but presently I am reluctant to try this due to needing to unbolt the PCBs from their heatsinks and possibly need to replace the insulating washers, which I am out of presently. I had a good chance to listen to the latest rips made using the USB Regen yesterday through the main system. WOW !
Kind Regards Alex |
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Post by jeffc on Oct 29, 2015 10:15:12 GMT
Hi Chris,
Your integrated build is lookin' really impressive, well done, you must have soldering RSI after stuffing all those PCBs :-). I've been busy with work, bugger it, and struggling when I get a sec with getting my preamp boards cased, but I'm getting there slowly and will report soon. Also while pondering this preamp build I decided to fix a few non-ideal things in my Class A HA that used those trick thick PCBs. This has resulted in some minor butchering and stolen more of my time than I hoped it would.
Alex, a question on the DC offset corrector, while I had the HA PCBs out, I placed a 4n7 film cap under the board across the 1M resistor. Is this still recommended before I do the same for the preamp offset corrector. And on the lowering of the input HF filter cap to 68pf, options I have are using a silver mica or pilfering the polystyrene from my Class A HA and replacing this with the silver mica. I thinking the latter as I like PS caps in this spot, but open to suggestions?
cheers.. jeffc
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Post by Deleted on Oct 29, 2015 10:26:19 GMT
Hi Jeff Yes, do the same for all offset correctors. It shouldn't matter which type of 68pF you use there except ceramic. .
Kind regards Alex
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jc
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Post by jc on Oct 29, 2015 16:55:13 GMT
Haha! I felt like a production line in Asia when stuffing all those JLH boards!
I'd forgotton about that. My notes for the power amp boards say a 2n2 across the 1mR, is that still right or was it changed to 4n7 like the pre?
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Post by Deleted on Oct 29, 2015 20:21:22 GMT
Haha! I felt like a production line in Asia when stuffing all those JLH boards! I'd forgotton about that. My notes for the power amp boards say a 2n2 across the 1mR, is that still right or was it changed to 4n7 like the pre? Hi Chris The noise floor is set by the Preamp mainly, and 4n7 appears to be slightly better there. I wouldn't expect as much improvement when changing from 2n2 to 4n7 in the P.A. Besides which, it's a lot more work unbolting the PCBs in the P.Amp. and refitting them , checking for s/c to heatsink etc. again.
Regards Alex
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jc
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Post by jc on Oct 30, 2015 13:12:59 GMT
Cheers Alex, the older pair has 4n7 on the pre and 2n2 on the power, the new pair now have 4n7 all round.
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pingu
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Post by pingu on Oct 19, 2016 18:51:39 GMT
Hi back after a while.
Been looking for the thread on Greg's new PSU, anyone point me in the right direction please. Looking for the diodes to use 1N4004, anything better?
I have some sf14s but someone on here mention a good fast diode too. Anyone any ideas
Martin
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Post by PinkFloyd on Oct 20, 2016 21:02:38 GMT
Martin,
I've done my best to locate Alex but he doesn't appear to have a forum of his own....... I'm sorry I couldn't be of more help mate.
Mike.
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pingu
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Post by pingu on Oct 20, 2016 23:30:19 GMT
Thanks Mike, I'll try them Not sure who Greg is but I am sure I have on old book mark for his website.........somewhere The thread on the PSU must have been one of the ones that went. I'm sure I read it on here Sorry to hear Alex has departed he was very helpful. Luckily I have several PSU boards from Alex's / Gregs last design so I have enough for the amps and another little HA by R Marsh that has been passed on to me so no probs Outdated JLH designs mmmmmmm well outdated like an air cooled 911 Porsche is. Old but still puts the power down  and the JLHs are not cheap look on here. But then I use Quads or SE 300Bs and ESLs they save on the heating in the winter too when I sit down with my pipe and slippers. |
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pingu
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Post by pingu on Nov 5, 2016 19:38:15 GMT
Martin, I've done my best to locate Alex but he doesn't appear to have a forum of his own....... I'm sorry I couldn't be of more help mate. Mike. Mike I have located some SF16 diodes cheap too and almost twice as fast as the ones you suggested (btw that post seems to have gone too). So I'll use those for now Thanks anyway |
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Post by PinkFloyd on Nov 5, 2016 21:35:32 GMT
Martin, I've done my best to locate Alex but he doesn't appear to have a forum of his own....... I'm sorry I couldn't be of more help mate. Mike. Mike I have located some SF16 diodes cheap too and almost twice as fast as the ones you suggested (btw that post seems to have gone too). So I'll use those for now Thanks anyway Hi Martin, They should fit the bill nicely. I'm really sorry about the posts that were deleted, there was a bit of a school playground fight here and a few people threw their toys out of the pram. I got in touch with Craig Suffolk at Proboards and asked him to restore the forum to the way it was before the toys were thrown out of the pram but, unfortunately, there was nothing he could do about it. Here is a link to my proboards support query: support.proboards.com/thread/588891/restore-forumI am pretty pissed off too Martin, there was a lot of good content in those posts..... rest assured that the LAST thing this joint needs is a "loss" of content and it was very sad to see the loss of a valued contributor and many of his posts on July 04th 2016. He probably thought it was reversible but, sadly, it appears not  Let us know how you get on with the SF16 diodes Martin....... All the best, Mike. |
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pingu
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Post by pingu on Nov 5, 2016 22:12:33 GMT
Hi Mike
These things happen no probs
Thanks for your help, pity they could not restore from backups so much for " once it's out there it's there for ever"
I'll let you know how SF 16s work
Regards
Martin
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Post by videoguy on Dec 8, 2016 5:54:31 GMT
Hi Martin: I assume the diodes are for an AKHA. The SF16 are ok but the amplifier board should use an SF12 of SF14.
I will keep an eye on this thread or you could send a P.M., to me. I have had my amp up & running for 3 weeks; it sounds great. I should be able to answer any of your questions.
Bill W.
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pingu
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Post by pingu on Dec 14, 2016 19:48:40 GMT
Hi Bill
Sorry for the delay and thanks for the offer of help. Much appreciated
The sf16's were for Gregs PSU that I got for dirty boards. I have used the now for the PSU and all seems to be OK
Have also got a couple of ripple eaters done too
When I get more time I'll start on the AKHA boards properly
Thanks
Martin
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and the JLHs are not cheap look on here. 