Hi all,
I'm looking for a SE 300B design that delivers just a little more power that a normal 300B. I guess 15 Watt will do the job but like to stick to SE.
I found this design, using a KR300BXL from KR Enterprice that is said to deliver > 15 Watt operating at 514V @ 135mA. What do you think about this design?
amp http://www.triodedick.com/big_c/big_c copy.gif
PSU http://www.triodedick.com/big_c/big_c_v copy.gif
Thanks, Ralph
I'm looking for a SE 300B design that delivers just a little more power that a normal 300B. I guess 15 Watt will do the job but like to stick to SE.
I found this design, using a KR300BXL from KR Enterprice that is said to deliver > 15 Watt operating at 514V @ 135mA. What do you think about this design?
amp http://www.triodedick.com/big_c/big_c copy.gif
PSU http://www.triodedick.com/big_c/big_c_v copy.gif
Thanks, Ralph
Ralph,
the KR300BXL is the best 300B avaiable IMO. It rather sonds like 45 than like a 300B while having much power.
The amp schematics look reasonable to me. Just one objection: this is a single ended amp which is no constant load for its PS.
A CLCLC filter for B+ certainly has a good static filter effect but on load changes it shows a step response taking eternally for coming to rest.
Suggestion: download PSUD II and simulate your power supply. You will see that a simple LC or CLC filter responds much friendler on load changes.
the KR300BXL is the best 300B avaiable IMO. It rather sonds like 45 than like a 300B while having much power.
The amp schematics look reasonable to me. Just one objection: this is a single ended amp which is no constant load for its PS.
A CLCLC filter for B+ certainly has a good static filter effect but on load changes it shows a step response taking eternally for coming to rest.
Suggestion: download PSUD II and simulate your power supply. You will see that a simple LC or CLC filter responds much friendler on load changes.
Hi Bernhard,
Thanks for your comments. I'm aware of the fact that the PSU has some problems, I've simulated it in PSU designer. I was in the first place very interessted in the comments about the amplifier schematic itself. Seems a bit complicated, and I've found another schematic today http://www.audiodesignguide.com/my/300blxs_amp_sch2.gif
What do you think?
Ralph
Thanks for your comments. I'm aware of the fact that the PSU has some problems, I've simulated it in PSU designer. I was in the first place very interessted in the comments about the amplifier schematic itself. Seems a bit complicated, and I've found another schematic today http://www.audiodesignguide.com/my/300blxs_amp_sch2.gif
What do you think?
Ralph
Ralph,
this second one would rather be my choice. Although methinks with a 6SL7 a SS constant current source will work better than a plate choke. The 6SL7 has a plate resistance too high; the choke's inductivity might be too low to give you a proper lower bandwidth limit.
I would replace the Jensen coupling caps by SiemensEpcos MKV 25839. By any means! And for the 6SL7, i would try to get my hands on a vintage redbase RCA 5691 or vintage metal base Sylvania 6SL7.
this second one would rather be my choice. Although methinks with a 6SL7 a SS constant current source will work better than a plate choke. The 6SL7 has a plate resistance too high; the choke's inductivity might be too low to give you a proper lower bandwidth limit.
I would replace the Jensen coupling caps by SiemensEpcos MKV 25839. By any means! And for the 6SL7, i would try to get my hands on a vintage redbase RCA 5691 or vintage metal base Sylvania 6SL7.
check this site in The Netherlands for a complete transformerset for the amp at Triodedick's site (kr300xls included)
http://www.ae-europe.nl/trafosets.htm
jim
http://www.ae-europe.nl/trafosets.htm
jim
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