Hold on, there is still a bit of fingernail on one of my fingers to bite off.
Sorry chief, say again ?
Using 1295/3294s is a bit overkill, though. 6 of those make an excellent output stage for a +200 watt amplifier with their 230 volt rating.
Their casing is excellent for class A use, and have been used for a number of class A designs.
One audio designer overhere, who is into class A amplifiers from the start, exclusively uses them nowadays. Must be short to 20 years ago at an audioshow that he told me he used ringemitter devices in his amplifiers.
Sorry chief, say again ?
Using 1295/3294s is a bit overkill, though. 6 of those make an excellent output stage for a +200 watt amplifier with their 230 volt rating.
Their casing is excellent for class A use, and have been used for a number of class A designs.
One audio designer overhere, who is into class A amplifiers from the start, exclusively uses them nowadays. Must be short to 20 years ago at an audioshow that he told me he used ringemitter devices in his amplifiers.
Fuzzy on thermal tracking
Looking at the Krell KSA-100 Mk II restoration pictures at http://home.ca.inter.net/~lloyd.maclean/Krell/Krell.htm, it is my understanding that the output devices for each channel are installed around one of the tunnel heatsinks, while the drivers and bias sense devices are mounted on separate heatsinks.
I was thinking of building my KSA-50 as monoblocks, in the usual configuration where two large heatsinks make the sides of the case. Three TO-247 devices would be mounted on each side while the drivers and bias sense devices would be mounted on separate heatsinks. Would that work? Could you guys please comment on that?
Looking at the Krell KSA-100 Mk II restoration pictures at http://home.ca.inter.net/~lloyd.maclean/Krell/Krell.htm, it is my understanding that the output devices for each channel are installed around one of the tunnel heatsinks, while the drivers and bias sense devices are mounted on separate heatsinks.
I was thinking of building my KSA-50 as monoblocks, in the usual configuration where two large heatsinks make the sides of the case. Three TO-247 devices would be mounted on each side while the drivers and bias sense devices would be mounted on separate heatsinks. Would that work? Could you guys please comment on that?
Grimberg,
Just be sure to place the bias device between the drivers on what ever sink you place them on... so you have decent thermal tracking. It may also just work fine sensing the temperature if you mounted the drivers and bias device on just one sink..... in theory the other sink ought to follow along at the same temperature.
Anthony,
Did you get both packages?
Jacco,
Yours should not be too far behind but the UK is pretty speedy with Priority mail.... one of the fastest in fact.
There are still about 30 boards left if anyone wants to join in this most civilized of all DIY threads!!
Mark
Just be sure to place the bias device between the drivers on what ever sink you place them on... so you have decent thermal tracking. It may also just work fine sensing the temperature if you mounted the drivers and bias device on just one sink..... in theory the other sink ought to follow along at the same temperature.
Anthony,
Did you get both packages?
Jacco,
Yours should not be too far behind but the UK is pretty speedy with Priority mail.... one of the fastest in fact.
There are still about 30 boards left if anyone wants to join in this most civilized of all DIY threads!!
Mark
Hi Mark,
Yes I got both packages thanks very much the boards look great, I'm going to start them this weekend.Cant wait to bi amp my kefs.
A couple of questions..
With the psu boards which TO220 diodes are used in the bridge rec. Also what kind of value resistors are used that link the first group of capacitors to the last.
Regards
Anthony
Yes I got both packages thanks very much the boards look great, I'm going to start them this weekend.Cant wait to bi amp my kefs.
A couple of questions..
With the psu boards which TO220 diodes are used in the bridge rec. Also what kind of value resistors are used that link the first group of capacitors to the last.
Regards
Anthony
Anthony,
You can find the spreadsheet with the parts list here:
http://www.diyamps.com/aleph/docs/ps-parts-list.xls
You can find the spreadsheet with the parts list here:
http://www.diyamps.com/aleph/docs/ps-parts-list.xls
or download the latest version of Duncan's PSU designer and pick capacitor and resistor values yourself :
http://www.duncanamps.com/software.html
http://www.duncanamps.com/software.html
Parts GB-
Yesterday I rx'ed "part" of the Welbonre labs order.
I will be emailing and calling them later today to find out why it took 2 weeks to get a "partial" order.
Needless to say, I was not impressed with their service.
I have the shipping material and have started separating out the components.
I have not started the semis yet in hopes of someone explaining how to measure the transistors.
As soon as the rest of the parts arrive from Welborne Labs I will begin mailing out.
Yesterday I rx'ed "part" of the Welbonre labs order.
I will be emailing and calling them later today to find out why it took 2 weeks to get a "partial" order.
Needless to say, I was not impressed with their service.
I have the shipping material and have started separating out the components.
I have not started the semis yet in hopes of someone explaining how to measure the transistors.
As soon as the rest of the parts arrive from Welborne Labs I will begin mailing out.
pinkmouse said:
Fellow Krell mates,
words fail me, utter utter utter disappointment.
(pronounce the way of Rik in "The Young Ones", or as Otto in "A fish called Wanda")
Anyway, marvellous boards. Thank you, Al, Thank you, Mark.
Now that i have them, i've updated the Krell build wiki with info of my version.
As with the Leach boards i have, i need to drill a lot of holes to size to fit all the hardware i am using.
Anthony,
i suggest you place your output devices a bit away from the output boards, Q506 and Q503 are just short of 40 mill.
The Phillipines connection for MT200 Mica insulators was not succesfull for me, lost 25 bucks for trying.
If anyone knows a manufacturer of MT200 AL2O3 insulators, i have not found one yet ?
For the moment i am getting MT200 Micas from the shop around my corner: BMM electronics recently dropped the price from $2 to $0.70 the piece.
Over and Out.