leo
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Post by leo on Jan 2, 2008 16:39:29 GMT
Pagan, I have a pair of 22v 5A E/I frame traffo's I was going to use for the classA. These E/I frame type traffo's have dual outputs, I can't decide if to wire them as centre tapped using one rectifier for each or use the dual outputs with a pair of rectifiers for each. With other amps I've built normally the dual outputs with dual rectifiers sound better but with this one being classA and using regulation maybe it won't make a difference. Anyway I've now 2 x main reg boards (same as SC article) set to output +/-20v to the amp section. I wasn't sure if Alex was running the main amp regs to the output section and then running the JLH's off the main regs output to the input stage too. If the sound is as good using 1 x JLH , separate reg, 1 x small traffo as it is using dual mono then I'll stick with using the single JLH route etc, I was hoping to fit as much of the electronics in a single case with maybe having the traffo's in a separate case So many choices to start with I'd rather do the same as you guys seeing as though its proven to sound good
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Deleted
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Post by Deleted on Jan 2, 2008 22:01:49 GMT
Hi Leo,
As Alex seems off-line at the moment so.....
Alex has used one main toroid, but it looks like it has 2 sets of secondaries. He has 2 bridge rectifiers with each feeding a single SC main reg board.
There is a small toroid for the front end. This feeds a single JLH. I can't see clearly the rectifier so I don't know what it is. There is a feed from the rectifier to 2 DC offset servos. Alex doesn't always use the DC offset servos.
The pictures I am looking at are from earlier this year, but should be close to the current amp. If you PM me your email address I can forward you some pictures.
regards
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pagan
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Post by pagan on Jan 2, 2008 22:08:09 GMT
Leo As i can see a pic of the psu. Looks as follows. One box for PSU. One transformer with two bridges to two regs for the outputs. (dual dc out) so dual mono from bridges. One small transformer approx 30va for front end. (ac out) In amp box reg'd dc to outputs. separate for each channel AC to single reg, then JLH, then to amps front end, both channels. When i used the SC15w, I tried the standard transformer first. ie single tranny reg etc, was a sweet sounding amp standard. Then later i tried a single 300va 25vac tranny reg'd to 24vdc and upped the bias better bass ps already had doubled size of heatsinks
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pagan
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Post by pagan on Jan 2, 2008 22:10:15 GMT
Hi Greg you beat me to it ;D
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leo
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Post by leo on Jan 3, 2008 1:16:50 GMT
Thanks guys , much appreciated! soon I can see what all the fuss is about around this amp I'm also tempted to give the SC UL100w a go after this. Pagan, you have both the 100w and the 15w classA ? how do they compare in your opinion? Its going to be interesting comparing these against my modified Hypex UCD's , Avondale NCC200, Burson PI-100 and Aksa N+
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pagan
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Post by pagan on Jan 3, 2008 2:24:58 GMT
Thanks guys , much appreciated! soon I can see what all the fuss is about around this amp I'm also tempted to give the SC UL100w a go after this. Pagan, you have both the 100w and the 15w classA ? how do they compare in your opinion? Its going to be interesting comparing these against my modified Hypex UCD's , Avondale NCC200, Burson PI-100 and Aksa N+ Between the standard 100W and standard 15W? The 100W was very accurate almost clinical, I preferred the 15watt, just a sweet sounding amp. I've heard modded versions of these both. SandyK's and a friend of his, Dave. Dave did a lot of mods to a SC ULD100W and it sounded awesome. Compared to SandyK's highly modded 15W? hard to say, not much in it at all. I did prefer SandyK's just for the soundstage, almost holograghic. but not much in it at all. Whether this has something to do with Class A bias, hard to say. I had the newly built(one week old) modded(before JLH's) SC20Watt there. My SC20W+ was beaten by the other two, but did surprise use all. JLH's now fitted, still need to do SandyK's input mods
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leo
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Post by leo on Jan 3, 2008 2:34:16 GMT
Thats great, I'm really looking forward to trying it, I'm going to fit the JLH's,mods etc to start with, I've almost got everything now anyway, the input stage mods are already fitted
Only main problem for me is the case but at least I can screw the big heatsinks to a base unit and try it through the main speakers
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pagan
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Post by pagan on Jan 3, 2008 3:53:36 GMT
Thats great, I'm really looking forward to trying it, I'm going to fit the JLH's,mods etc to start with, I've almost got everything now anyway, the input stage mods are already fitted Only main problem for me is the case but at least I can screw the big heatsinks to a base unit and try it through the main speakers Try it without the JLH's first. Would be interesting on your view of there differences? "but at least I can screw the big heatsinks to a base unit" Done that before ;D Every now and then they end up in cases very rarely with a top cover.
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leo
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Post by leo on Jan 3, 2008 12:52:58 GMT
I'll try without them first then and post the results, should be interesting, the JLH looks a nice circuit. Out of interest anybody know if theres suitable transistors that would let the JLH handle about 1A load? I'd like to try one with something else
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Post by Deleted on Jan 3, 2008 13:15:46 GMT
Thanks guys , much appreciated! soon I can see what all the fuss is about around this amp I'm also tempted to give the SC UL100w a go after this. Pagan, you have both the 100w and the 15w classA ? how do they compare in your opinion? Its going to be interesting comparing these against my modified Hypex UCD's , Avondale NCC200, Burson PI-100 and Aksa N+ Hi Leo, I'm also building a SC UL 100w and 15w class A (slowly). I started these before I heard Alex, Pagan and Dave SC amps. Mine will start off standard because I'm interested in the sound of standard kits. How similar are the NCC200 and AKSA N+ soundwise? I've built lots of amps but always seem to end up using my AKSAs. Alex made us QA the boards he sent you, so you can be assured they sounded very good in his setup before be ripped them out. regards
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pagan
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Post by pagan on Jan 3, 2008 13:45:52 GMT
Out of interest anybody know if theres suitable transistors that would let the JLH handle about 1A load? I'd like to try one with something else I exchanged emails with "Jaap" from diyaudio a fair while ago, He was trying for about 4amps at under 5volts!!! Don't think he succeeded thought, I'll ask him and see how far he got. IMHO i think it's a case of diminishing returns Higher the current the more power the trannies need to be able to handle. The higher the power capabilities of the tranny, the slower they are. Would be interesting to run them and turn up the current while watching on a crow.
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FritzS
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Post by FritzS on Jan 3, 2008 15:27:49 GMT
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leo
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Post by leo on Jan 3, 2008 18:06:54 GMT
Thanks guys , much appreciated! soon I can see what all the fuss is about around this amp I'm also tempted to give the SC UL100w a go after this. Pagan, you have both the 100w and the 15w classA ? how do they compare in your opinion? Its going to be interesting comparing these against my modified Hypex UCD's , Avondale NCC200, Burson PI-100 and Aksa N+ Hi Leo, I'm also building a SC UL 100w and 15w class A (slowly). I started these before I heard Alex, Pagan and Dave SC amps. Mine will start off standard because I'm interested in the sound of standard kits. How similar are the NCC200 and AKSA N+ soundwise? I've built lots of amps but always seem to end up using my AKSAs. Alex made us QA the boards he sent you, so you can be assured they sounded very good in his setup before be ripped them out. regards Hi Greg, Aksa N+ is a nice amp, tbh I prefer the NCC200, I find the Aksa sounds less realistic, smaller soundstage, it adds lots of signature to the sound I find a bit fake tbh although saying that I have a friend who likes my Aksa better than my NCC200 in his set up. Both are good amps and I can see why each has its own followers. I've heard and tried a lot of amps, the ones I don't use get given away, I still have the Aksa,NCC200 and modded Hypex so I guess these are my favourite 3 so far Cheers, Leo
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leo
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Post by leo on Jan 3, 2008 18:12:45 GMT
Out of interest anybody know if theres suitable transistors that would let the JLH handle about 1A load? I'd like to try one with something else I exchanged emails with "Jaap" from diyaudio a fair while ago, He was trying for about 4amps at under 5volts!!! Don't think he succeeded thought, I'll ask him and see how far he got. IMHO i think it's a case of diminishing returns Higher the current the more power the trannies need to be able to handle. The higher the power capabilities of the tranny, the slower they are. Would be interesting to run them and turn up the current while watching on a crow. I was thinking it may be interesting to try one of these with a Squeezebox3, a few places are now offering expensive external 5v supplies with big claims. My own SB3 is already highly modded but was interested to try something like the JLH with a standard unit to see if it actually does improves things, it needs to be about 1amp, I know theres an internal switcher in these units but going by the hype these external supplies are still supposed to make the JLH may have been a cheaper alternative for the diyers
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leo
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Post by leo on Jan 3, 2008 18:13:35 GMT
Good find Fritz, I'll have a read through those taa
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pagan
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Post by pagan on Jan 5, 2008 14:09:43 GMT
[quote author=leo board [/quote] I was thinking it may be interesting to try one of these with a Squeezebox3, a few places are now offering expensive external 5v supplies with big claims. My own SB3 is already highly modded but was interested to try something like the JLH with a standard unit to see if it actually does improves things, it needs to be about 1amp, I know theres an internal switcher in these units but going by the hype these external supplies are still supposed to make the JLH may have been a cheaper alternative for the diyers [/quote] audio equipment with switching psu! yuk!! analogue it instead. Separate psu's for digital and analogue supplies. If possible, look at the grounds for these too. Try to separate earths for digital and analogue then back to a star earth. Even separate psu's using LM3*7's with well implemented layouts should improve it. Then JLH selected areas
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leo
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Post by leo on Jan 5, 2008 19:15:34 GMT
I was thinking it may be interesting to try one of these with a Squeezebox3, a few places are now offering expensive external 5v supplies with big claims. My own SB3 is already highly modded but was interested to try something like the JLH with a standard unit to see if it actually does improves things, it needs to be about 1amp, I know theres an internal switcher in these units but going by the hype these external supplies are still supposed to make the JLH may have been a cheaper alternative for the diyers audio equipment with switching psu! yuk!! analogue it instead. Separate psu's for digital and analogue supplies. If possible, look at the grounds for these too. Try to separate earths for digital and analogue then back to a star earth. Even separate psu's using LM3*7's with well implemented layouts should improve it. Then JLH selected areas [/quote] I already did analogue mine Infact mine has a modified VBE frontend ALW regulation, modified SPDIF output witha Newava pulse traffo for dacs with a SPDIF in and reclocked I2S feeding a better dac direct . I was thinking for other guys wanting to try a simple supply without having to rip things apart
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Post by Deleted on Jan 8, 2008 4:56:36 GMT
"Leo As i can see a pic of the psu. Looks as follows. One box for PSU. One transformer with two bridges to two regs for the outputs. (dual dc out) so dual mono from bridges. One small transformer approx 30va for front end. (ac out)"
Leo The dual windings of the larger transformer feed 2 x 35A 400V BRs for dual mono.
The smaller transformer is a 30VA 15-0-15VAC transformer , which ONLY feeds AC to the Class A preamplifier. Power for the JLH which feeds BOTH front ends , is taken from ONE of the Class A's DC input sockets. (from a single Regulator PCB.) I didn't think there would be much advantage to using 2 JLHs . i.e. FULLY dual mono. I may explore the possibility of using individual JLHs at a later date, as so far , everything else seems to make a worthwile improvement. Alex I haven't a clue why it insists putting the message at the side !!!! I've had 3 attempts.
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leo
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Post by leo on Jan 8, 2008 15:27:51 GMT
Hi Alex, Thank you for the detailed description, its much apprciated your layout is proven to work spot on so will get mine as close as poss I think somethings screwed up with the posts, if you notice my last post was laid out weird too
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pagan
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Post by pagan on Jan 13, 2008 9:03:15 GMT
is this thead view fix yet?
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pagan
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Post by pagan on Jan 13, 2008 9:04:24 GMT
apparantly not
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Post by dc on Jan 13, 2008 10:51:06 GMT
it was leo's post, he had some funky code in his post
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Post by Deleted on Jan 13, 2008 11:11:43 GMT
Perhaps he just mounted it at the wrong angle ?
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Post by dc on Jan 13, 2008 11:31:39 GMT
Perhaps he just mounted it at the wrong angle ? oh no! my industry secrets are getting reverse engineered by leo!?!?!
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pagan
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Post by pagan on Jan 13, 2008 11:49:23 GMT
Perhaps he just mounted it at the wrong angle ? Does this mean. beware of Leo's angle? Also Leo!! how are the amps coming along? or a different angle....... Were you up to bro
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