Pink Mouse,
I know what you mean! This is my version 1.01 and I still should move the output semi's further up the sink for better efficiency accoding to another person in this thread. But sedign changes never hurt and we all learn form them. At this point with my dual 12 volt DC fans running at 5.5 volts the semis are a comfortable 50 deg c. and I am pretty happy with that. I also measured the temp of Q-107, 108 and they seem to free air idle at about 48 deg.c. which I am also comfortable with. I just thought it better to mount the drivers someplace so they run at a comfortable margin, they do get really, really hot other wise!
Mark
I know what you mean! This is my version 1.01 and I still should move the output semi's further up the sink for better efficiency accoding to another person in this thread. But sedign changes never hurt and we all learn form them. At this point with my dual 12 volt DC fans running at 5.5 volts the semis are a comfortable 50 deg c. and I am pretty happy with that. I also measured the temp of Q-107, 108 and they seem to free air idle at about 48 deg.c. which I am also comfortable with. I just thought it better to mount the drivers someplace so they run at a comfortable margin, they do get really, really hot other wise!
Mark
Mark A. Gulbrandsen said:
Glad you Pioneers are working out the kinks for laggards like me. 😀
Hi
With so many people building- there seems to be very little feedback in this forum in terms of how does the amp sound?
It would be very interesting to compare the clone version with a original.
Does anybody have a fully completed amp working by now ?
Jozua
With so many people building- there seems to be very little feedback in this forum in terms of how does the amp sound?
It would be very interesting to compare the clone version with a original.
Does anybody have a fully completed amp working by now ?
Jozua
Hmm....
While cutting the traces related with the SVRs, I realized how good the quality of the pcb is.
Really hard to cut. The foil is thick and is strongly attached to the board....
While cutting the traces related with the SVRs, I realized how good the quality of the pcb is.
Really hard to cut. The foil is thick and is strongly attached to the board....
"Really hard to cut. The foil is thick "
Well that would be the extra thick traces I ordered to ensure the boards were high quality and could handle the current demands of class-A.
I've never heard anyone say a Krell was wimpy.. I've heard many other things, but not wimpy, cheap, or flimsy.
Well built was always an adjective used. 🙂
Well that would be the extra thick traces I ordered to ensure the boards were high quality and could handle the current demands of class-A.
I've never heard anyone say a Krell was wimpy.. I've heard many other things, but not wimpy, cheap, or flimsy.
Well built was always an adjective used. 🙂
I've been listning to mine for almost two weeks now. Its not in a chassis as of yet... that part takes time
!
How does it sound? Very similar to my old KSA-80. Great bottom end and overall slam, turns bad sounding cd's into really bad sounding cd's and good ones are pure magic. This amp does not bahave like a 50 watt amp, but then the KSA-80 didn't behave like an 80 watt amp either.....
This weekend I will convert it into dual mono with a second power transformer, bridge and caps. Then the fun'll really begin😀
I can keep my heat sink temp to 50 deg c more or less as I have an air tunnel arrangement set up with 2- 12 volt dc fans running at a bit under half speed.
Mark
!How does it sound? Very similar to my old KSA-80. Great bottom end and overall slam, turns bad sounding cd's into really bad sounding cd's and good ones are pure magic. This amp does not bahave like a 50 watt amp, but then the KSA-80 didn't behave like an 80 watt amp either.....
This weekend I will convert it into dual mono with a second power transformer, bridge and caps. Then the fun'll really begin😀
I can keep my heat sink temp to 50 deg c more or less as I have an air tunnel arrangement set up with 2- 12 volt dc fans running at a bit under half speed.
Mark
Well, I'm sulking...
I started wiring up my outputs on my angle brackets, and dicovered that I'd drilled the pin holes offset in the wrong direction on one of the Ls.
Oh well, I'll have to fire up the drill press again tomorrow.
I started wiring up my outputs on my angle brackets, and dicovered that I'd drilled the pin holes offset in the wrong direction on one of the Ls.
Oh well, I'll have to fire up the drill press again tomorrow.
An interesting thing I noticed after much listening to my KSA-50 was that after it was on more than three or four hours the top end tended to get a bit too laid back. In my case I believe that the drivers, and bias were just running way, way too hot. Since mounting them on the main heat sink this problem has vanished.... two sessions now with the amp on in excess of five hours per session and the top end no longer has this excessive laid back effect. It'll be interesting to see if anyone else notices this or experiences this same effect. Oddly, I had this same effect when I built a "stock" Aleph X. As a result I scrapped the X amp idea completely. Apparently I needed alot more sink real estate for the X as well.
P.S. This KSA-50 is fantasitc in my system!
Mark
P.S. This KSA-50 is fantasitc in my system!
Mark
How hot?
Hey mark,
What temp were your drivers running at after 4 hours???
Mine are 60-65 deg...
Aaron
Hey mark,
What temp were your drivers running at after 4 hours???
Mine are 60-65 deg...
Aaron
Algar_emi said:
Very nice! But you need a good chassis to place it in too,.
Question:
What are D1/D2 for?
Did you consider 2.5 to 3 mH coils?
"The Power Supply I will use."
Algar_emi,
I assume that this supply is for one channel? A 3.5 amp SB fuse definately will not hold for 2 channels. Its an impressive supply!! I have a box full of 6mh torodial chokes... would they work well in that supply?
"Hey mark,
What temp were your drivers running at after 4 hours???"
Almost 70 deg. c., now they are at sink temperature which is about 52 deg. c..... I thought that 70 deg was just a tad too hot for those little guys..... after many thermal cycles that means sooner failures and possible DC on the speakers! The amp seems to settle down quicker as far as bias and offset. Settles down in about 15 min now. With the drivers on that small HS that I had made it took quite a while for the output to settle down to near just a few mv. Bias also drifted around for quite a bit longer. NOw you can watch it change for about 15 min and then it just hangs at 420 mv and a few mv of dc on the output.
Mark
Algar_emi,
I assume that this supply is for one channel? A 3.5 amp SB fuse definately will not hold for 2 channels. Its an impressive supply!! I have a box full of 6mh torodial chokes... would they work well in that supply?
"Hey mark,
What temp were your drivers running at after 4 hours???"
Almost 70 deg. c., now they are at sink temperature which is about 52 deg. c..... I thought that 70 deg was just a tad too hot for those little guys..... after many thermal cycles that means sooner failures and possible DC on the speakers! The amp seems to settle down quicker as far as bias and offset. Settles down in about 15 min now. With the drivers on that small HS that I had made it took quite a while for the output to settle down to near just a few mv. Bias also drifted around for quite a bit longer. NOw you can watch it change for about 15 min and then it just hangs at 420 mv and a few mv of dc on the output.
Mark
K-amps said:
Presumably protecting the bridges from spikes generated by coils when power is switched off (although capacitors should absorb the spike).
I think you should still consider room for DC blocking capacitors (on transformer's primary side). Even the best transformers will be prone to buzz if saturated by DC from the mains.
Bratislav
KSA50 is typical of the 80's high-end vogue genre - no surprises, nothing special! PCB layout will make or break it's value. Pretty ordinary really.
What do you listen to this time, gentleman, when thing, which is twonyfive years old, make your enthusiasm ? Don't tell me, that you are every poor 😉 .
Don't tell me, that you are every poor 😉 .