spritzer Posted February 1, 2013 Report Posted February 1, 2013 Those two amps look brilliant!! As for the offset Wachara, most of that is due to the Ixys part.
eggil Posted February 1, 2013 Report Posted February 1, 2013 Those are very nice amplifiers. Congratulations to both!
shipsupt Posted February 1, 2013 Report Posted February 1, 2013 Wow, two great looking builds. Lots of inspiration!
JoaMat Posted February 1, 2013 Report Posted February 1, 2013 Very nice! Interesting versions of chassis. Well done.
schubert Posted February 1, 2013 Report Posted February 1, 2013 Hi everybody, My assembly is finished, during test, everything was ok : 15V, 450V, balance 200mV, offset 9V (à bit heavy..) BUT after 15 mn, the two 4700uF started to boil and the BR1 bridge is hot !!! Any idea ?
spritzer Posted February 1, 2013 Report Posted February 1, 2013 They are backwards or they are fed to much voltage.
headinclouds Posted February 2, 2013 Report Posted February 2, 2013 They are backwards or they are fed to much voltage.My first thoughts as well. He's got both the 15v supplies so I suspect overvoltage.I do think that the 25v rating of the 4700uF is cutting it a bit close. I bought mostly what's on the BOM on trust. But I am very tempted to find a similar 35v part. There is no room for mains fluctuations either. If the mains is high we might get over 25v.What value of raw low voltage dc are others getting?schubert will you please measure and let us know the ac voltages going into the PS at the terminals. and the raw low voltage dc. You only need to take a "minute" and then switch it off.you could also check your ac mains voltage coming into the whole thing.
RiStaR Posted February 2, 2013 Report Posted February 2, 2013 Hi all, I'm new here and about to start on this build. I've already gotten some help from Victor (thanks!) and Tran (for helping with the boards). I've ordered most of the parts but am having trouble tracking down the following (not exactly but they are on all different vendors which want to charge USD30-40 shipping each as I'm in Singapore). I was wondering if someone out there had spares and would be willing to ship it to me at my expense? The silicon I'm after are: LSK389 x 2 (or more) 2sa1486 x 10 (or more) 2sc3840 x 4 (or more) lt1021-10 x 2 (or more) 2SC4686A x 12 (or more) 2SC2705 x 4 (or more) 2SC2240 x 4 (or more) 2SA970 x 4 (or more) 2SC1815 x 2 (or more) Thanks in advance for any possible help! Also, I've been going through the thread and can't seem to find any recommendations for transformers that work in 240v. Could someone point me to that thread? (Search doesn't seem to have helped there).
spritzer Posted February 2, 2013 Report Posted February 2, 2013 All the transistors except the LSK389 can be had from bdent.com and the LSK from Trendsetter. You need custom transformers for this amp so somebody like SumR could build them for you. They can be ordered with two 117V primaries which are then series connected for 240V. If you can live with +/-400V rails then there is this one from Edcor. A small toroid for the low voltage and the end bells can be removed to mount the transformer inside a chassis. I did just that in my B10 with M4 hardware and I'll use this transformer to make a souped up KGSS soon.
RiStaR Posted February 2, 2013 Report Posted February 2, 2013 Hi Spritzer, Bdent was the first I tried... they don't have the quantity eg. they only have 1 x 2SC2705. Maybe I'll try again in a few days and thanks for the advice on the transformer! Edit: Just to be sure... bdent.com directs me to http://www.bdenterprisesinc.com/ so I hope that's right? All the transistors except the LSK389 can be had from bdent.com and the LSK from Trendsetter. You need custom transformers for this amp so somebody like SumR could build them for you. They can be ordered with two 117V primaries which are then series connected for 240V. If you can live with +/-400V rails then there is this one from Edcor. A small toroid for the low voltage and the end bells can be removed to mount the transformer inside a chassis. I did just that in my B10 with M4 hardware and I'll use this transformer to make a souped up KGSS soon.
spritzer Posted February 2, 2013 Report Posted February 2, 2013 I have some extra 2SC2705's. They seem to be branching out into more components so that is their new site.
schubert Posted February 2, 2013 Report Posted February 2, 2013 My pb is solved, a very stupid mistake on 18V PS connection.... Some pictures of the amp. Still have a little issue with my alpha pot, but music is near !!!!
schubert Posted February 2, 2013 Report Posted February 2, 2013 Bigger pics and my 4700uF looking like mushrooms... waiting for new ones
Victor Chew Posted February 2, 2013 Report Posted February 2, 2013 Congratulations. Nice build. What is the issue with the alpha pot?
RiStaR Posted February 2, 2013 Report Posted February 2, 2013 I'll take em I sent you a pm about the Alpha Quads as well (well if you have some left) Ok, I'll finalize my Bdent order tomorrow. I just can't seem to find one last component on BDent.com: LT1021-10 (do you happen to have 2 of them, too? ) Thanks Spritzer and Headinclouds (for the transformer). Pretty stoked i'm getting everything in soon I have some extra 2SC2705's. They seem to be branching out into more components so that is their new site. I have some extra 2SC2705's. They seem to be branching out into more components so that is their new site.
spritzer Posted February 2, 2013 Report Posted February 2, 2013 I'll drop you a PM about the 2705's later on. As for the Alpha issues, the PCB is upside down so all the connections are in the wrong place. On a 3 pin pot it would just work backwards but this one is 4 pin...
kevin gilmore Posted February 2, 2013 Author Report Posted February 2, 2013 wiring the transformer to the low voltage supplies with the center tap in the wrong place is definitely going to cause the caps to over voltage.
headinclouds Posted February 2, 2013 Report Posted February 2, 2013 Well done schubert!That didn't take long and it looks very nice.Glad the little problem is sorted.
chinsettawong Posted February 2, 2013 Report Posted February 2, 2013 wiring the transformer to the low voltage supplies with the center tap in the wrong place is definitely going to cause the caps to over voltage. I did that once with my DIY T2 PS.
headinclouds Posted February 2, 2013 Report Posted February 2, 2013 Well done schubert!That didn't take long and it looks very nice.Glad the little problem is sorted.Calling you schubert like that.Are you going to have a go at finishing that symphony?
chinsettawong Posted February 2, 2013 Report Posted February 2, 2013 For the time being, this is a quick and easy fix for my ventilation problem.
schubert Posted February 2, 2013 Report Posted February 2, 2013 Music is flowing, finaly. Very hudge sound, so much more power than my T1, everything is better, soundstage coming more in front, dynamics, and à lot more. Many thanks to all of you. À big thank you to Spritzer, à hudge one to head incluons !!!! )
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