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Post by rossman on Jun 21, 2008 20:58:39 GMT
Thanks for this Mike. It will be very useful when I come to do the board.
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Post by canjunkie on Jun 21, 2008 21:36:16 GMT
Nice one Mike Just got back from a late night session down the shed - 14 boards Alex, She who must be obeyed got to watch her film in peace so all is well Just remember guys, Mike has a 'Special Edition' version with room for the extra caps (6 instead of 4) Mike, have you tried it alongside the standard 4 cap version?
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Post by sometrolls2 on Jun 21, 2008 21:44:23 GMT
Great post.
Any comments on electrolytic selecetions? Often the post regulator cap has a great impact on sound, what about caps in the middle of the board which enhances the regs?
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Post by Deleted on Jun 21, 2008 21:55:27 GMT
Mike The PCB you are using appears to be the alternate version to my recently put together one from Dave's artwork. That is, + and - are on different sides of the PCB. BUT, all Toshiba devices should face in the same direction. On the +VE side, the 2SC5171s should face the outside of the PCB. On the -VE side, the 2SA1930 should face the centre of the PCB. The originally posted photo with the attached pinout is correct. However, the top Toshiba 2SC5171 in the photo, does give the appearance of being reversed. It isn't! It is at a slight angle due to being a tight fit on previous PCB layouts, which were designed by Allan to use the slimmer BD139/BD140. Alex
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Post by Deleted on Jun 21, 2008 22:31:48 GMT
sometrolls2 The output impedance is so low that the type of capacitor at the output (100uF) and Subsequent capacitors don't have much influence. Using 4x 1,000uF low ESR capacitors in lieu of 2 x 2,000uf low ESR,only made a barely detectable difference, as did the use of 4 x generic 1,000uF parallel capacitors in the old original version. In the X-DAC V3 , for instance, I used 100uF Elna Stargets either side of the added 78L12/79L12 for the analogue section with a warmer resulting sound. After the JLH was inserted at the output of the outboard dual regulated PSU, their influence was no longer noticed. This is because the impedance of the non current limited JLH is far below the minimum impedance of these bypass capacitors. Alex
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Post by canjunkie on Jun 21, 2008 22:35:51 GMT
Mike,
I definitely have the Toshi Trannies facing the same way with emitters towards the output of the board on both rails. On the +ve side the Emitter of the BC639 connects to the base of the first 2SC5171 then to 0V via the 33R resistor. The emitter of the 2nd '5171 connects to 0V direct. If you've got the schematic that Alex sent over it should help get them the right way round. I've also marked the emitter pads with an 'e' on the boards.
I think the confusion comes from one of the early photos which appears to have one of the +ve trannies facing the other way.
If thats the earlier board, which if it is on the opaque SRBP PCB I think it is, it does have the +ve/-ve the other way round to the later ones. This was done mainly to match up with the SC/Jaycar PSU & headamp boards. The GRP translucent board I sent you is this way round.
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Post by Deleted on Jun 21, 2008 23:17:51 GMT
Mike Please see previous edited post Alex Attached is a retouched photo and pinout. Click on the image for a larger photo.
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FritzS
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Post by FritzS on Jun 22, 2008 15:31:10 GMT
Mike The PCB you are using appears to be the alternate version to my recently put together one from Dave's artwork. That is, + and - are on different sides of the PCB. BUT, all Toshiba devices should face in the same direction. On the +VE side, the 2SC5171s should face the outside of the PCB. On the -VE side, the 2SA1930 should face the centre of the PCB. The originally posted photo with the attached pinout is correct. However, the top Toshiba 2SC5171 in the photo, does give the appearance of being reversed. It isn't! It is at a slight angle due to being a tight fit on previous PCB layouts, which were designed by Allan to use the slimmer BD139/BD140. Alex At my PCB's (single and dual) the description on the copper side is mirror-inverted - I must compare this with Mikes photos. The only fussy components are the BJT's and the electrolytics - there are non OPA's Mike, Alex - thanks for the very good description I have a WNA cascode PSU PCB (two cascoded LM317) - is this true necessary if I use the JLH "ripple cleaner"? Alex - what PCB's did you recommand from RCS Radio or others for LM317 / LM337 single +24V and dual +- 15V PSU's This regulators I have in my stock - are this useful? National LM350AT Linear Technologie LT1085CT +3A +2,5 .... +25V LT1085IT +3A +2,5 .... +25V LT1185IT -3A -2,5 .... -25V (my mistake I mean LT1185 not the LT1186!) LT1086IT #PBF +1,5A +1,2 .... +15V LT1086CT-12 +1,5A +12V LT1086IT-12 +1,5A +12V LT1086IT-5 +1,5A +5V
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Post by PinkFloyd on Jun 22, 2008 21:29:22 GMT
Shit! I feel so embarrased... I basically went by the original photo Alex and assumed the transistor was reversed All rectified now and will listen tomorrow. Why on earth have I got BC556 / BC549? You appear to have BC559 / BC549 on yours? Time I invested in a new pair of specs I think
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Post by Deleted on Jun 22, 2008 21:42:00 GMT
Mike BC556 is fine for the -VE side, unless they have low HFE, and will be useful if you want higher voltage working. BC549C, BC550C are O.K. for the +VE side. BC550C and BC560C are available from RS, and ideal for higher voltage working. The "C" versions were recommended by JLH because of their higher HFE. Selected higher HFE specimens of BC549 and BC559 are also suitable,as are selected high HFE versions of BC548 and BC558.Most recent DMMs have a transistor test facility. Alex
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Post by canjunkie on Jun 22, 2008 22:04:41 GMT
Shit! I feel so embarrased... I basically went by the original photo Alex and assumed the transistor was reversed All rectified now and will listen tomorrow. Hey Mike, show me an engineer who says they've never put a tranny or an electro cap in BTF and I'll show you a liar Me - I did it in style on a control board for a rather large generator on location somewhere quite close to you (about 70 miles I think). I bought the beer for quite a while for that one Didn't help that I'd just had a ding dong with the producer about being unable to change the laws of physics just to get his shot. His repost after a rather loud bang was something like 'OK but thanks for trying'
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Post by Deleted on Jun 22, 2008 23:05:51 GMT
FritzS The LT1085CT appears to be a suitable replacement for the LM317T. The LT1186IT did not appear in a Google search. The others are not suitable for this project. The PCB thats is needed for the SC Dual Regulated PSU, is SC01109052. It is Bin 3040 at RCS Radio. As I said in my email reply,the LT1085CT appears to be a suitable replacement for the LM317T. The LT1186IT did not appear in a Google search. The others are not suitable for this project. The PCB that is needed for the SC Dual Regulated PSU, is SC01109052. It is Bin 3040 at RCS Radio. As I said in my email supply, Dave may be able to supply a suitable dual regulated adjustable PSU PCB, which is about the same size as the kit PCB. Ask him nicely . Alex
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Post by sometrolls2 on Jun 23, 2008 6:12:13 GMT
The LT1086 fixed regs are just adjustable regs that have the adjustment resistors internalised, so they can be adjusted with additional resistors.
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Post by FritzS on Jun 23, 2008 7:55:24 GMT
FritzS The LT1085CT appears to be a suitable replacement for the LM317T. The LT1186IT did not appear in a Google search. Alex, my mistake - I mean LT1185 www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1040,C1019,P1465 The LT1185 is a 3A low dropout regulator with adjustable current limit and remote sense capability. It can be used as a positive output regulator with floating input or as a standard negative regulator with grounded input. The output voltage range is 2.5V to 25V, with ±1% accuracy on the internal reference voltage.
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Post by Deleted on Jun 23, 2008 10:03:50 GMT
Friedrich The LT1185 regulator is obviously not suitable in this application due to number of pins and configuration. The previously mentioned adjustable regulator PCB is designed for use with the LM317/LM337 adjustable regulators, and 3 pin top adjusting, multi turn, 2K ohm trimpots. Other manufacturers also supply their versions of the 317/337. Alex
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Post by FritzS on Jun 23, 2008 16:19:56 GMT
Friedrich The LT1185 regulator is obviously not suitable in this application due to number of pins and configuration. The previously mentioned adjustable regulator PCB is designed for use with the LM317/LM337 adjustable regulators, and 3 pin top adjusting, multi turn, 2K ohm trimpots. Other manufacturers also supply their versions of the 317/337. Alex Alex, "yes sir" I have seen it to late ;D AFAIK the LM350A is the 3A version of the LM317A (1,5A), I have 5 pcs of LM350A in my stock
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Post by Deleted on Jun 23, 2008 21:03:51 GMT
In general, the higher output rated voltage regulators may have less effective bandwidth due to the larger pass devices used. The 78Lxx/79Lxx,for example, have wider bandwidth than the 78xx/79xx, although they do have a higher output impedance. Alex
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Post by Will on Aug 6, 2008 19:19:41 GMT
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Post by canjunkie on Aug 6, 2008 21:45:01 GMT
Wilbur, Looks pretty good to me Nice work
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Post by Deleted on Aug 6, 2008 22:45:03 GMT
Wilbur Which devices are you using in place of the 2SA1930 on the -VE rail side ? I think CJ is right about the rest. (Assuming resistor values are correct) Alex
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Post by Will on Aug 7, 2008 6:08:56 GMT
Guys, thanks for looking over the board.
Alex, I'm using 2SA1930 on the -ve rail, from cricklewood electronics. I think they are Toshibas.
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Post by Deleted on Aug 7, 2008 6:32:21 GMT
Wilbur Are they definitely marked 2SA1930 ? The only Toshiba 2SA1930 that I have seen are in a black plastic type insulated pack.That is all my data sheet shows too. Alex
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Post by leo on Aug 7, 2008 10:36:28 GMT
Is that 10uf cap the right way around on the pos rail?
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Post by Deleted on Aug 7, 2008 11:40:30 GMT
Leo You are right. It is the wrong way around on the +VE rail. When I checked originally, there was only the photo with the black border around it. Alex
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Post by canjunkie on Aug 7, 2008 14:13:35 GMT
Sorry Wilbur, too busy checking the orientation of the semis to spot the capacitor Alex, The 2SA1930's supplied by Cricklewood electronics come in that 220 package, although the 5171's are in the all plastic type housing. The '1930's are clearly marked as well.
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