pinkmouse said:As all the veterans are appearing again, I thought I'd post too.
The low bias Klone is still running well, but the monster is in storage, pending new PSU caps. One day it will be finished, I promise.
Low bias?
That's a bit weak! All you need are bigger sinks and bigger fans...
My 2 channel from memory (i have a mains power monitor) drains about 800-900w from the mains at idle!!! So i've got some serious bias on mine... From memory it was setup to do about 110w RMS @ class A into 6 ohms.... Or something like that! My output temp is about 63deg on the 'hotter' side. But that's only 33deg above ambient (it's hot in Aus)I'm over in the UK after travelling around europe for 1.5mths... We've got ourselves jobs here, etc and are just seeing how long it lasts before we head home! Likely a year or two at a rough guess. It's quite nice here... I bet you've never heard someone say that before
Good to see everyone is still kicking about!
Aaron
Stuffed KSA-50 PC boards for sale
Krell KSA-50 Clone stuffed PC boards for sale Post #1
HI
Up for sale a pair Krell KSA-50 PC boards (from grop buy made by Pinkmouse2005)
The PC board stuffed all the resistors like Holco ,PRP some Kiwame . All transistors are closly matched ,soldered by WBT silver solder .
Also I include with the kit 6pair MJ21193 / MJ21194 TO3 metal case .
I use ERO Vishay , Panasonic FC tipe (10uF 50V),some silver mica and Wima capacitors
The bord vas carefully ansemled , never powered up .I change my mind I build in the amplifier case a Aleph4.
So I only I sell these because I need the money for my next project .
My heatsink is way to large 15" tall 45lb for the Krell so I desided to biuild in a Aleph 4 .
I ask for the pair kit $170 plus shipping plus pay pal fee . It cost me much more the exotic parts , matched transistors etc .
I try first on the forum after 2 weeks I will post it to the Ebay .
If you are interested please write to mathelaszlo2@yahoo.ca
Krell KSA-50 Clone stuffed PC boards for sale Post #1
HI
Up for sale a pair Krell KSA-50 PC boards (from grop buy made by Pinkmouse2005)
The PC board stuffed all the resistors like Holco ,PRP some Kiwame . All transistors are closly matched ,soldered by WBT silver solder .
Also I include with the kit 6pair MJ21193 / MJ21194 TO3 metal case .
I use ERO Vishay , Panasonic FC tipe (10uF 50V),some silver mica and Wima capacitors
The bord vas carefully ansemled , never powered up .I change my mind I build in the amplifier case a Aleph4.
So I only I sell these because I need the money for my next project .
My heatsink is way to large 15" tall 45lb for the Krell so I desided to biuild in a Aleph 4 .
I ask for the pair kit $170 plus shipping plus pay pal fee . It cost me much more the exotic parts , matched transistors etc .
I try first on the forum after 2 weeks I will post it to the Ebay .
If you are interested please write to mathelaszlo2@yahoo.ca
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NUTTTR said:
Low bias?
That's a bit weak!
***
I'm over in the UK after travelling around europe for 1.5mths... We've got ourselves jobs here, etc and are just seeing how long it lasts before we head home! Likely a year or two at a rough guess. It's quite nice here... I bet you've never heard someone say that before
Good to see everyone is still kicking about!
Aaron
Hey Guys! I've also been missing for years now, got a few intermediate posts, but the Krell is doing great, except I'm on my 3rd power switch now...anyone else with an old Krell been going through these?
I've not been DIYing much at all but a few things are still on the drawing board. In fact not much audio at all over the last 2 years. Then again, I cannot help but go to the surplus store and look at empty test equipment and large heat sinks, buying as many as I can justify for use later on......
Happy to see PinkMouse and Stewart are continuing to provide advice, just like the old times!
lgreen said:
Power switch? Nah... I use a 12v circuit (powered separately from the mains) to turn on 2x240v 20amp airconditioner relays
These things can handle serious turn on surge! They aren't massively big and they are also reasonably quiet! Very cheap from memory, and they've lasted very very well!Aaron
In-surge-nce
My most recent Krell builds have used Cl-60 type thermistors to limit the power on inrush, no idea how long the power switches will last, but this has to help.
After I moved off the variac, but until I fitted the thermistors I went through a lot of fuses. With the amp idling the thermistors drop ~0.5v of the 115v I see at the house. So simple and effective it's scary. Each channel has a 625va transformer feeding 30000uF, one thermistor in series with each primary (110v each), now 3.15A fuses last indefinitely, though we'll probably fit 5A for real use.
The amps of which I am speaking will be at BAF2008, and I think are on the demo schedule, so anyone interested will be able to see and hear them.
Stuart
My most recent Krell builds have used Cl-60 type thermistors to limit the power on inrush, no idea how long the power switches will last, but this has to help.
After I moved off the variac, but until I fitted the thermistors I went through a lot of fuses. With the amp idling the thermistors drop ~0.5v of the 115v I see at the house. So simple and effective it's scary. Each channel has a 625va transformer feeding 30000uF, one thermistor in series with each primary (110v each), now 3.15A fuses last indefinitely, though we'll probably fit 5A for real use.
The amps of which I am speaking will be at BAF2008, and I think are on the demo schedule, so anyone interested will be able to see and hear them.
Stuart
hi..i want to ask you something about the differences of these circuits..i want to make krell amp..my friend made krell ksa 100 with four output transistors and two mje15030-31..but there is cascaded mje 15030-31 transistors in ksa50 circuit..what are the sonic differences between them..thanks
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umut1001 said:
Hi Umut,
in my honest opinion, few DIY Krells will sound the same as the DIY community has made modifications over the years, some for better and some for worse.
A Krell is not necessary the best sounding amplifier in any case, but if you are looking for the original sound then build the original amplifier.
The KSA 100 circuit you show will not give you the 100 watts at class A biasing with a single set of output devices as you will be over stressing them, unless forced cooling is used.
Have a look at the original KSA100 guts.
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hi.i will try it semi class a or quarter class a mode.not fully biased class a .i am asking the why delta audio circuit has three cascaded mje15030-31s..because its hard to match them..i bought 4 pieces of matched mje15030-31..i will use it with my westra speakers.theyre capable of 70watts rms 120watts nominal power..i dont know who draw the picture of krell ksa100..can it drive 4pairs of output transistors with only a pair of mje15030-31?
.i am asking the why delta audio circuit has three cascaded mje15030-31s..because its hard to match them..i bought 4 pieces of matched mje15030-31..i will use it with my westra speakers.theyre capable of 70watts rms 120watts nominal power..i dont know who draw the picture of krell ksa100..can it drive 4pairs of output transistors with only a pair of mje15030-31?