I'd be willing to bet that the type of outputs you use won't matter all that much unless you used something thats old and very with very low bandwidth. I think the characteristic of this amp is achieved with whats on the main board and there only to some extent. Its the topology of the thing that gives it its own characteristic.
Al, What are you going to change now? Guess youe E-mail is back up.
Mark
Al, What are you going to change now? Guess youe E-mail is back up.
Mark
Mark A. Gulbrandsen said:
NOTHING!!!
🙂
Nah, that'll be a few days yet, but I'm at work today and tomorrow so I get the odd ten minutes here and there to pop in...
I'll mail you my work email in case you need to get in touch...
Old stuff:
risetime ~ 0.35/ cornerfrequency.
80s Krell's had slewrates in the order of 15 Volts/ uS.
50 watts in 8 Ohms = 28.28 Vp.
Means cornerfrequency is ~ 190 kHz.
Measured -3 dB frequency response of KSA50/100 was like 2Hz-125 kHz, due to the inputfilter.
Original MJ15003/4 have a 2MHz bandwidth.
risetime ~ 0.35/ cornerfrequency.
80s Krell's had slewrates in the order of 15 Volts/ uS.
50 watts in 8 Ohms = 28.28 Vp.
Means cornerfrequency is ~ 190 kHz.
Measured -3 dB frequency response of KSA50/100 was like 2Hz-125 kHz, due to the inputfilter.
Original MJ15003/4 have a 2MHz bandwidth.
Hi,
I was planning to use 5200 in Leach clone but after buying them and then checking SOAR against reactive load decided they did not suit the higher voltages (+-58V). .
So I now plan to use them in the Krell Klone where +-40V suits them better. I plan to use 5 or 6 pairs. Don't let that 230v rating deceive you like it did me.
Very good gain, good heat dissipation, very good bandwidth are all going to help improve the Klone with a bit of luck or should that be good design.
I was planning to use 5200 in Leach clone but after buying them and then checking SOAR against reactive load decided they did not suit the higher voltages (+-58V). .
So I now plan to use them in the Krell Klone where +-40V suits them better. I plan to use 5 or 6 pairs. Don't let that 230v rating deceive you like it did me.
Very good gain, good heat dissipation, very good bandwidth are all going to help improve the Klone with a bit of luck or should that be good design.
How did you test the 5200 SOAR? Did you blow a few or do u have a curve tracer? +/-58v seems low enough... I guess not.
Hi,
I didn't physically test it.
I planted the SOAR data into a slightly modified version of Bensen's spreadsheet & the graphs told me that the numbers do not stack up, even though the derating above 45V does not look that bad initially.
I now plan to use 4281 or 21194 for the Leach clone.
I didn't physically test it.
I planted the SOAR data into a slightly modified version of Bensen's spreadsheet & the graphs told me that the numbers do not stack up, even though the derating above 45V does not look that bad initially.
I now plan to use 4281 or 21194 for the Leach clone.
I have used 3 parallel 2SC3281/1302 (class AB amp) with 68V rails (500VA transformer on each channel and 120000µF) for 8 years into 6 ohm passive speaker. I have driven the amp into clipping without the transistors ever failing.
I think it's great to calculate the worst case situations, but be careful with choice of load impedance and so on.
I know it might be off topic, but why not start doing some actual work to understand what happens with inductive loads and make some sort of database of how many of a certain output pair is needed in order to work into a specific impedance at some different rail voltages?
\Jens
I think it's great to calculate the worst case situations, but be careful with choice of load impedance and so on.
I know it might be off topic, but why not start doing some actual work to understand what happens with inductive loads and make some sort of database of how many of a certain output pair is needed in order to work into a specific impedance at some different rail voltages?
\Jens
Not yet Al but I will definately do this over the next day or so. Its hard for me to bring the KSA-50 down in the basement to do the measurements so I just may bring the 1701A upstairs to the krell instead! Am still feeling the healing after effects of the surgery that I had just over a month ago so gotta be careful. Will post em asap.
Did you get my e-mail about closing the WIKI and getting the group order imderway?
Mark
Did you get my e-mail about closing the WIKI and getting the group order imderway?
Mark
Attention !
In a day or two the group buy will be closing. I will e-mail everyone thats on the group buy list just in case a few have not been checking back here on a regular basis.
When you get my e-mail about this please e-mail me back at ksa50amp@yahoo.com so I have your real name, address to ship to, insurance or not, and so on and so forth, and the exact qualtities you want to purchase. This way I can calculate the shipping for each order based on the quantities you order, the more we have made the less expensive they will be. I would prefer to send them in the U.S. by Proirity Mail, and the remainder by Global Priority Mail. Global Priority is probably the safest and quickest way to ship to over seas buyers.
After I hear back I will e-mail again with your total due and payment can be made either via PayPal or by Snail Mail.
So far there are 40 definate purchasers out there...... I guess Terry pulled out....
Thanks!
Mark
In a day or two the group buy will be closing. I will e-mail everyone thats on the group buy list just in case a few have not been checking back here on a regular basis.
When you get my e-mail about this please e-mail me back at ksa50amp@yahoo.com so I have your real name, address to ship to, insurance or not, and so on and so forth, and the exact qualtities you want to purchase. This way I can calculate the shipping for each order based on the quantities you order, the more we have made the less expensive they will be. I would prefer to send them in the U.S. by Proirity Mail, and the remainder by Global Priority Mail. Global Priority is probably the safest and quickest way to ship to over seas buyers.
After I hear back I will e-mail again with your total due and payment can be made either via PayPal or by Snail Mail.
So far there are 40 definate purchasers out there...... I guess Terry pulled out....
Thanks!
Mark
Hi GeWa,
these types of transistors have very similar parametres, so without problems you can use both types 😎 .
these types of transistors have very similar parametres, so without problems you can use both types 😎 .
Hi!
Does anyone knows original specs of ksa-50 such as slew rate, damping factor, rise time, etc.?
Regards🙂
Does anyone knows original specs of ksa-50 such as slew rate, damping factor, rise time, etc.?
Regards🙂
neychi said:
1983 test:
noise level : ~ 0.15 mV(A)
damping: +100 between 50Hz-10KHz, variation <6%.
slewrate : 14 V/us
power: 78 watts/8 (1 % distortion), nearly 200/2
(same mag tested the KSA100 at 160 watts/8 in 1986 btw, 280/4, 400/2)
Thanks Jacco!
Slew rate is very low in compare to ksa -80 wich have 500 V/us according to Krell's brochure. Is it any difference between mkI and mkII models in specs? I know that 15V/us is enough even for fastest signals but I'm just curious.
Slew rate is very low in compare to ksa -80 wich have 500 V/us according to Krell's brochure. Is it any difference between mkI and mkII models in specs? I know that 15V/us is enough even for fastest signals but I'm just curious.
neychi said:
Hi-
500 or 50? Bryston has 60 V/us which is one of the higher examples on the market. I would be suprised to see any consumer amp to have greater than 100 V/us (much less 500 V/us).
Hi Troy
is not easy " hold " stability of very fast amp, what you can see at one nice example : Spectral make very fast amps and they are very proud of declared results, which look good at promotion
😉 . But they at the same time recomend to connect their amps to boxes by one special cable, which iclude " massive " choke for suppression of high frequencies. You can ask why 😀 .
is not easy " hold " stability of very fast amp, what you can see at one nice example : Spectral make very fast amps and they are very proud of declared results, which look good at promotion
😉 . But they at the same time recomend to connect their amps to boxes by one special cable, which iclude " massive " choke for suppression of high frequencies. You can ask why 😀 .
The Krell brochures that i saw in the 80s were all pretty standard, from the KSA50 to the KMA400:
s/n: 120dB
Dampingfactor: 500
Harmonic distortion: < 0.1 %
Intermodulation distortion: < 0.1 %
Only exception was the Krell Altair.
A Spectral with 500V/uS would probably make me reach for tranquilizers.
s/n: 120dB
Dampingfactor: 500
Harmonic distortion: < 0.1 %
Intermodulation distortion: < 0.1 %
Only exception was the Krell Altair.
A Spectral with 500V/uS would probably make me reach for tranquilizers.
Attention Again !
I will be letting the group buy go for one more week due to a death in the family. But next Monday is the last straw at which time everyone will receive the pay up e-mail from me for the boards they ordered.
Mark
I will be letting the group buy go for one more week due to a death in the family. But next Monday is the last straw at which time everyone will receive the pay up e-mail from me for the boards they ordered.
Mark