G600 Posted December 3, 2014 Report Posted December 3, 2014 Nice work Muskyhuntr ! Do you guys have an advice for 2N5564 testing ? I have scored a pair at a very low price from a regional seller, I was told they are genuine (and they were the last two in stock). How to verify that ?
GrindingThud Posted December 4, 2014 Report Posted December 4, 2014 Do this: http://www.diamondstar.de/transistor_matching_jfet.html Make sure Idss meets spec. Very easy with some alligator clips, ammeter, and 9V battery. Works well. I was able to sort out a mess of 2SK170-BL for another project. Had an epic fail procurement on my 2SJ74-BL.....out of spec Idss, but I may have enough to do what I need.
nopants Posted December 18, 2014 Report Posted December 18, 2014 If Craig is ok with it I can post the mods he suggested
G600 Posted December 23, 2014 Report Posted December 23, 2014 Gents, I'm tailoring the last mouser order for my Klone. Which pot do you recommand ? Especially what value ? Thanks and merry Xmas
kevin gilmore Posted December 23, 2014 Author Report Posted December 23, 2014 input pot? dual alps 10k (mouser does not sell this) or anything else you can get that is 10k.
muskyhuntr Posted December 23, 2014 Report Posted December 23, 2014 I used a Goldpoint in mine and have been very happy. Me
kevin gilmore Posted December 23, 2014 Author Report Posted December 23, 2014 sure, but that costs almost as much as the rest of the amp especially if you go for the 47 position model
G600 Posted December 28, 2014 Report Posted December 28, 2014 (edited) I went very nuts with the power transformer. I've just paid for a 50VA "custom order" by Canterbury Windings, with electrostatic shield and a goss band. Planning to put the Klone in a single chassis, I'll see how clean it can be. Edited January 2, 2015 by G600
G600 Posted January 20, 2015 Report Posted January 20, 2015 New PSU is running. By the way, which headphone is the best pairing with this amp ?
G600 Posted January 24, 2015 Report Posted January 24, 2015 (edited) Output transistors not yet properly mounted... Edited January 24, 2015 by G600
CraigBuckingham Posted January 28, 2015 Report Posted January 28, 2015 (edited) If Craig is ok with it I can post the mods he suggested nopants, sorry for the late reply, not always reading all the threads here frequently. I would prefer you don't post anything as "my mods", instead maybe you can try one thing at a time and if you like the result, post it as something you tried without any reference to me. It's a clone and I don't want to actively promote diversion away from the intent of the thread and project. Edited January 28, 2015 by CraigBuckingham
G600 Posted February 10, 2015 Report Posted February 10, 2015 I have powered up the amp. Bias was very easy to set, but I don't experience the decribed negative tempco : my bias stays quite the same after warming up. Offset is around 40 on one side, and 80 mV in the other, without the OP27 of course. Everything looks quite stable, and the temperature is lower than what I expected. Don't know if I'll wait for a scope before first listening with el cheapo cans...
Earspeakers Posted March 15, 2015 Report Posted March 15, 2015 The circuit diagram show plain resistor loads on the input drivers, any reason those aren't CCS's? A simple LM317 load kills any resistor in my tests.
kevin gilmore Posted March 16, 2015 Author Report Posted March 16, 2015 you should ask this question in the megatron thread, but there is a constant current source at the cathodes, and you can't do dual current sources. The current source at the cathode is necessary to keep the differential gain high. you could replace the cathode constant current source with a resistor, then do more of the same current sources as the second stage.
Luke Posted March 21, 2015 Report Posted March 21, 2015 Hi All, anyone have a spare set of boards for this project?
samsie Posted May 24, 2015 Report Posted May 24, 2015 anyone have a spare set of boards ? Please pm 1
sorenb Posted June 23, 2015 Report Posted June 23, 2015 Finished populating my KSA5 today. Tried to match transistors since I had a stash of mpsw06/56 from my dynalo builds ... it really takes a considerable amount of time if one lets the transistor stabalise before testing the next. The build it self wasn't particular complicated, but one has to take care that all transistors get into the right place and have the right orientation ... well, I guess everybody here knows that, but with so many trannies it is easy to miss one or two ... I did do that fuck-up building one dynalo ....ending up having 10V on the output ...anyways I manged to get through without any errors this time....that is almost ...turned out that I missed a 39pF and two .1uF when doing the BOM. Hook it up to a Sigma22 PSU at 2x24V ....without any smoke .... less than 50mV on the output (input grounded) ....put a load on and a signal ....everything seems fine .... this bastard gets hot when running ... I dare think of how hot it will get when ever I get around to boxing it A first listen using my HD800 sounds very promising. But so does the dynalo Thanks to Kevin/Birgir for bringing this clone to the community
sorenb Posted June 23, 2015 Report Posted June 23, 2015 @Grinding Thud ....oh yeah .....from back then ... actually my first ... bought it when it came out ... switch from Texas TI57 (miss that disply anyways) ...I don't collect ....but manged to have a few anyways: Actually its been years since I last did a program on the 15C ...did it today, matching some transistors ...a small program calculating the Hfe ....funny how things get stucked in your mind ....took less than 30s and off I went ... loving this flashing "running" when it steps through ten lines of code ...
GrindingThud Posted June 24, 2015 Report Posted June 24, 2015 Nice collection. I have a 15C but not used it in years...makes me want to break it out.
sorenb Posted June 24, 2015 Report Posted June 24, 2015 I hope you did remove the batteries before storing? or at least they haven't leaked ... there a few articles in PPC rgrd synthetic programming on the HP15C ... not of much use, but rather entertaining if you want to fiddle a bit with the intrinsic of Saturn
JoaMat Posted June 24, 2015 Report Posted June 24, 2015 Agree, nice collection. Remember when I switched from slide ruler to Texas T59 with magnetic card reader. That was a giant step forward.
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