HI
Today I picked up a pair transformer for these project .
Each transformer has a 39.8V-0-39.8V sec. 120V prim. and 8.8A .
Any opinion about these transformers .
I know it would be better if 10A or more but these transformers were very cheap .
May be I go a bit with a lower bias .
Regards
Today I picked up a pair transformer for these project .
Each transformer has a 39.8V-0-39.8V sec. 120V prim. and 8.8A .
Any opinion about these transformers .
I know it would be better if 10A or more but these transformers were very cheap .
May be I go a bit with a lower bias .
Regards
HI
Thanks .
I think is bigger than 700VA even they marked for 8.8A .
It is almost the same size like 1KVA Plitron .
I payed $30CAD for each .
I just tested under power they are nice quiet , for load I hook up the 1500VA hair dryer and no hum at all .
I hope it will be OK with a lower bias for the KSA-100 .
Regards
Thanks .
I think is bigger than 700VA even they marked for 8.8A .
It is almost the same size like 1KVA Plitron .
I payed $30CAD for each .
I just tested under power they are nice quiet , for load I hook up the 1500VA hair dryer and no hum at all .
I hope it will be OK with a lower bias for the KSA-100 .
Regards
I will definately have the G.B. up and running tommrrow night come hell or high water.... Just been busy with women and work, somehow I've amazingly been able to somewhat combine the two🙂 .
Mark
Mark
Zen Mod said:
Let me guess - you haven't had a 600W heater in your room when it is 42-43 degrees day outside ? Even with aircon on full blast I can feel the thing radiate heat from 3 meters away.
Big Krells work just fine biased at ~30W full class A (for me at least, and at least in summer).
You can always crank it up in winter if you feel like you're missing something. Mine are in fact sitting on ~1.5A bias all the time now. Can't really say I can hear much difference.
(this is with 16 pairs of 15003/4 in the output stage and with output feedback loop disconnected)
Bratislav said:
Sounds fantastic! 16 pairs of 15003/4! 😱 Can you share some pics. More fuel for the fire...😉
Cheers,
Shawn.
Hi,
what temperature does the heatsink run at?
What is the temperature difference between the sink and the aluminium spreader plate and between the spreader plate and the Q cases?
I think your transistors my be running a bit hot, particularly if you bias it up to the full value of 2.6A in the mk2 (what is the mk1 bias?).
what temperature does the heatsink run at?
What is the temperature difference between the sink and the aluminium spreader plate and between the spreader plate and the Q cases?
I think your transistors my be running a bit hot, particularly if you bias it up to the full value of 2.6A in the mk2 (what is the mk1 bias?).
Hi,
I read that the mk1 was a high bias ClassAB with the bias current set (from memory) to about 1.5A.
Maybe I shouldn't believe what I read.
I read that the mk1 was a high bias ClassAB with the bias current set (from memory) to about 1.5A.
Maybe I shouldn't believe what I read.
It's quite possible that that was the case on some of them - after all I've seen over 5 different KSA100 schematics so far where there's officially only two. The Mk1 I had under eyes had the same 620mA/transistor bias as the Mk2.
Bratislav said:
my "cranking" comment was related to 700VA xformers ability to drive stock biased one channel;
nothing more......
btw- bias issue is certainly related to exact amp-spks combo ,especially when you count on temp issues.......thinking of that-I'm lucky,just because temp in my place isn't higher than 35-38 Celsius at Summer
How about building a few KMA 100 revII's with a 2-level Class-A bias selector switch on the PCB? This strategy would give a pretty universal amplifier solution from one common design. I think a well designed KMA100, even with reduced bias, would have better sonics than the KSA50 based upon my past experience on my Apogees. The symmetric MOS diff-pairs should provide good isolation of the speaker's back EMF from the voice coil inductance, and a voltage regulator for the driver stages should extend this separation. This is why I suggested a single PCB KMA100 design suitable for a compact monoblock.
I'm interested how the ears on this tread think the DIY KSA100 and KSA50 compare.
My latest amp has a switch for 12A or 20A of Class-A bias. My power supply is only +/- 5V, but I still need two KL-271 tweleve inch long heatsinks.
I'm interested how the ears on this tread think the DIY KSA100 and KSA50 compare.
My latest amp has a switch for 12A or 20A of Class-A bias. My power supply is only +/- 5V, but I still need two KL-271 tweleve inch long heatsinks.
Krell Power Switch- Help ?
Hi
I received a quote from the local Krell agent for a replacement power switch for my Krell Mk2. Total cost - $400.00 !!
Does anybody know where one could source these switches from? It is not that I dont mind paying but $400-00 is a tad heavy for what I suspect is nothing more than a fancy trip switch.
Jozua
Hi
I received a quote from the local Krell agent for a replacement power switch for my Krell Mk2. Total cost - $400.00 !!
Does anybody know where one could source these switches from? It is not that I dont mind paying but $400-00 is a tad heavy for what I suspect is nothing more than a fancy trip switch.
Jozua
My KSA-100 biased at just 300mv blows the pants off the KSA-50 biased at spec.
Smoother mids and highs that are far better defined.
Neglagable congestion even at loud levels.
A soundstage depth and width that made my speakers virtually disappear.
A slam factor that rattles my front windows and floor!
Keep in mind that we have not actually built the KSA50 MK-2 version. I believe ours is a MK1.5 version. Until someone puts this pcb in a KSA-50 we won't have a fair comparison of the two MK-2 versions.
No, not quite... the metal for the contacts comes from this unobtanium mine in the west Utah desert... seceretly owned by Dan himself😀 . You can go in and get the switch material if you want to but its dangerous down there... snakes scorpions and large rolling boulders(not the amplifier) and poison darts... a job for Indy for sure.... or Dan for the price he is getting!
Mark
(Live from Stockman's Casino dinning room in Beautiful Elko Nevada!)
