niles said:
1. I think the transistors are pretty similar but recall someone looked at them at some point and thought both could be used.
2. Collective wisdom is that multiple small caps are better than big cans as they have lower ESR. Good luck with caps, might want to try jea capacitors on ebay (few pages back). Not as cheap as steve but way cheaper than mouser/digikey.
3. I can only say that the 2 700VA's in mine work great, If you have 2 500 VA I would think that would be sufficient.
Niles,
They are both similar, however there are some differences.
The 95/96 have better SOAR overall especially in lower Vce ratings. The 93/94 however edge out the 95/96 SOAR curve on about 100 volts so if you want to build a 500 watt amplifier with +/- 100 vdc, you will need lessor 93/94's. For almost all other rails, the 95/96 are more robust.
You can look at the curves to get a better picture.
They are both similar, however there are some differences.
The 95/96 have better SOAR overall especially in lower Vce ratings. The 93/94 however edge out the 95/96 SOAR curve on about 100 volts so if you want to build a 500 watt amplifier with +/- 100 vdc, you will need lessor 93/94's. For almost all other rails, the 95/96 are more robust.
You can look at the curves to get a better picture.
Last of the resistors are in. I rx'ed Stuarts last night.
Today is house work, tomorrow will be GB kit day.
I will advise again tomorrow. Once the kits are ready to be mailed out I will ask again for special requests. I had received some, but this thing has dragged on sooooo long they are blurred and I'd rather ask again than get it wrong.
EDIT:
I am very disapointed that we couldn't get ALL Dale RN60D resistors...
Today is house work, tomorrow will be GB kit day.
I will advise again tomorrow. Once the kits are ready to be mailed out I will ask again for special requests. I had received some, but this thing has dragged on sooooo long they are blurred and I'd rather ask again than get it wrong.
EDIT:
I am very disapointed that we couldn't get ALL Dale RN60D resistors...
ryssen said:Ok then I don´t use them,are they needed on the other board then?
I think they derive from one of the many versions of the KSA 50 schematics that we found on the WWW, and were put in on Jan's boards as an option because of that. I tried my protoypes with and without, and found no difference, so left them out to save space on the PCB. If you really want to use them, you can just tack them on underneath.
Anyone know a good source for 26-0-26 toroids?
I checked with Plitron and they have a 4-6week lead time and want $97 each for 500VA. I think that is high and quite a long lead time...
The par-metal guy on ebay doesn't seem to have 26V anymore and isn't responding to my inquiries.
Thanks,
Brad
I checked with Plitron and they have a 4-6week lead time and want $97 each for 500VA. I think that is high and quite a long lead time...
The par-metal guy on ebay doesn't seem to have 26V anymore and isn't responding to my inquiries.
Thanks,
Brad
Parts GB'ers
I got all the parts and kitted the JAN board kits. I will do the AL brd kits for the rest of the day and week until they are finished.
I have names and addresses but I need special instructions and kit type (Jan or Al) once more to ensure the right ones go to the right place.
Please send an email with the following info:
1. Kit type? (Jan or Al)
2. Special instructions? (86 this, declare x amount, etc..)
stgrab@yahoo.com
I have the paypal receipts printed out, but they don't show kit type and this is a chance to amend the request for shipping issues.
I got all the parts and kitted the JAN board kits. I will do the AL brd kits for the rest of the day and week until they are finished.
I have names and addresses but I need special instructions and kit type (Jan or Al) once more to ensure the right ones go to the right place.
Please send an email with the following info:
1. Kit type? (Jan or Al)
2. Special instructions? (86 this, declare x amount, etc..)
stgrab@yahoo.com
I have the paypal receipts printed out, but they don't show kit type and this is a chance to amend the request for shipping issues.
Keep watching E-Bay for Anateks stuff. He seemingly does run out of some toroids temporarily and he is really bad at answering mail. It once took about a week and a half for him to answer a friend and that answer was hard to unscramble... apparently he is Chineese or some foreign person whose english is not all that good. His transformers are ok for the $$ though. I've used two sets of them now in KSA-50's. Also don't forget that you can go to 40 volt rails without any problems or other needed mods so you might want to take a closer look at his 31 volt tranny.
Plitropn seems to be the most expensive but is probably the best of the bunch. You can also try these other quality toroid manufacturers.... I've also used both of them in past projects.
Toroid Corp Of Maryland
Avel-Lindberg
Mark
Having been so busy with work lately I decided to persue another method for a chassis for my KSA-50 and to finally get it "wrapped up". Yesterday I aquired a Smart 6 channel Cinema amp that has about the right size chassis. The sinks are a tad small however they are covered by a fan enclosure contianing two 4" DC fans. So I thought this ought to work just fine..... For those curious I didn't trash out any great or classic amplifier by any means. I'm not a Threshold chassis converter so to say! These amps have a long history of unreliability and a 6 in one channel amp just doesn't have a place in a cinema where if one channel goes it might take all 6 of them down and close that screen until the service man(yours truely) arrives. Well that is just what kept happenning to these wonderful amps which were built for Smart Drevices by AB systems. The amp itself is a rats nest of wires and a kludge in and of itself. It was a pleasure to lay this amp to rest! The next post contain some some photos of the before amp and of my planned layout for the KSA-50.... any input on the layout would be greatly appreciated!! BTW: I will be using the MJ21193/94 TO-3 devices salvaged from this amp for my KSA's final build. That will give me an extra 50 watts of disipation per device over using the MJL plastic pack devices, thats an extra 600 watts per channel of available disipation!
Thanks,
Mark
Thanks,
Mark
Attachments
Mark A. Gulbrandsen said:
I think that's better too have physically separated heatsinks for left and right channels.
just thinking how difference in C/W value of L/2 and 1L isn't linear (L of heatsink ,off course)
edit-just looking at layout of that amp-no wonder that is unreliable
btw-that fan case reminds me on old Altec amps
It has a black texture powder coat that looks ok. I am planning on making a new front panel though. Not trying to beat anyone here, just get My KSA-50 back in operation as I really need a second system here now....
Well, left and right channel do have seperate sinks but they are tied together using the alumnium angle that the TO-3's mount in. This also strengthens the sinks. I believe that with both fans doing about half speed it'll be livable... plus the TO-3's can take quite a bit more heat as well.
Mark
Wow, roomy, its like a Caddy!
I'm jealous!
Those heatsinks will be scalding hot with 3 pairs per channel of TO-3's, I wish (for your sake) that they were bigger but hey nothing you can do about that. Make sure you put in some feet and drill a hole or 2 for your bias sense/compensation transistor as I did not see a spot for it on your mounting bracket.
It will be heavy on the front side, so front handles will be a plus.
I'm jealous!
Those heatsinks will be scalding hot with 3 pairs per channel of TO-3's, I wish (for your sake) that they were bigger but hey nothing you can do about that. Make sure you put in some feet and drill a hole or 2 for your bias sense/compensation transistor as I did not see a spot for it on your mounting bracket.
It will be heavy on the front side, so front handles will be a plus.