The largest one is a joy if we give a joy to somebody.
You worked hard for this prize anyway.
The road was open to everyone.
From the funny transistor case you got have read here:
http://www.diyaudio.com/forums/pass-labs/84605-mounting-lu1014d.html
Gyuri
I know some of them: The "One Point Monitor" (with the predecessor SCS 3) and the "Cumulus Horn 2". Both very fine examples what you can do with this kind of driver.
Unfortunately Timmi's BLH has a veeery big and thus expensive crossover. Big - even for his standards.
But picture that horn - with all its qualities, driven by a 17cm Lowther, actively equalized and fired with a JFET-equipped transconductance amp like the F1J. A dream!
Unfortunately Timmi's BLH has a veeery big and thus expensive crossover. Big - even for his standards.
But picture that horn - with all its qualities, driven by a 17cm Lowther, actively equalized and fired with a JFET-equipped transconductance amp like the F1J. A dream!
Hm.... Did you hear Cumulus 2? My SCS4 was readymade, it is a little bit clumsy that the chasis and the readymade box have the same name.
Perhaps I could use some parts of the readymade crossover and save money ......
And you think the horn is suited for Lowther also? Would be a possibility to upgrade later and use F1j without crossover.
Could be a nice perspective for me ......
THX
Perhaps I could use some parts of the readymade crossover and save money ......
And you think the horn is suited for Lowther also? Would be a possibility to upgrade later and use F1j without crossover.
Could be a nice perspective for me ......
THX
Clone F1J Problem
I just purchased a used Rawson F1J clone. I had planned to build a F1J but couldn't find any boards. The sound is amazing on my Hornshoppe Fostex Fe 126E speakers. The music has more authority and weight than with my DIY parafeed SE 12b4 amp and is as satisfying in the treble. I've ordered boards to build an F3 amp to be used to drive the highs in my Emerald Physics CS2.3 speakers in my summer home system.
I'm having an intermittent problem with the Rawson F1J.
After it heats up a crackling sound can be intermittently heard over the music on both channels. After a 2-5 minutes of this intermittent noise the amp cuts off completely for a few seconds and then resumes normally as if nothing happened for an extended period of time. The good news I guess is that the problem is probably in the power supply as both channels are affected. My guess is that the CL60 thermister on the transformer primary circuit might be the problem. Any ideas?
I just purchased a used Rawson F1J clone. I had planned to build a F1J but couldn't find any boards. The sound is amazing on my Hornshoppe Fostex Fe 126E speakers. The music has more authority and weight than with my DIY parafeed SE 12b4 amp and is as satisfying in the treble. I've ordered boards to build an F3 amp to be used to drive the highs in my Emerald Physics CS2.3 speakers in my summer home system.
I'm having an intermittent problem with the Rawson F1J.
After it heats up a crackling sound can be intermittently heard over the music on both channels. After a 2-5 minutes of this intermittent noise the amp cuts off completely for a few seconds and then resumes normally as if nothing happened for an extended period of time. The good news I guess is that the problem is probably in the power supply as both channels are affected. My guess is that the CL60 thermister on the transformer primary circuit might be the problem. Any ideas?
The Rawson F1J is minimalist with a Plitron 300VA xformer and 10 inches of heat sink. It runs so hot that I can touch the heat sink for only 2-3 sec. There are no thermistors from the channel grounds to the chassis, in fact the AC plug ground is connected to nothing. There is no fuse. When TR upgraded it with JFETs he had to replace 2 power caps that had bulged. Should I call the bomb squad?
I have F1 power supply boards from SUDS that I can use to build a new PS according to NP specs using high quality parts. Look at the pics and tell me what you think.
Thanks....Ross
I have F1 power supply boards from SUDS that I can use to build a new PS according to NP specs using high quality parts. Look at the pics and tell me what you think.
Thanks....Ross
Attachments
more heatsinks
cut and toss entire wiring
pull out all parts from pcbs , clean them , check parts , solder them again
make new proper wiring
NTC flying in air ........ solution only if both leads are enclosed in tight silicone tubing
F1J Clone Fix
The closer I look at the Rawson F1J the worse it gets. The offset voltage for the speaker ouputs is 0.232 volts for the right and 0.474 volts for the left. I recall reading that resistors values in the constant current circuit should be changed until the DC offset is less than 0.050 volts. Is this something I should be concerned about? Does this mean that the SemiSouth R100s aren't matched close enough?
Thanks....Ross
The closer I look at the Rawson F1J the worse it gets. The offset voltage for the speaker ouputs is 0.232 volts for the right and 0.474 volts for the left. I recall reading that resistors values in the constant current circuit should be changed until the DC offset is less than 0.050 volts. Is this something I should be concerned about? Does this mean that the SemiSouth R100s aren't matched close enough?
Thanks....Ross
Educate me ZM, the solder joints look sloppy I can see, is that the complaint with the wiring? What is meant by " NTC flying in air"? I dont doubt you, just dont want to repeat same mistakes in my builds!
Thanks,
Russellc
wow ! hold your horses
ZM educating someone - that's certainly hilarious
solder joints are messy
wiring is messy
NTC soldered directly to mains socket and switch ; you can do the same - but you must extend NTC leads and dress them in proper silicone insulation
bare mains contacts on both switch and IEC socket
anyway ...... everything is just sloppy
take your time - search for pictures ( and there are plenty of them ) of decent made amps and you'll see what is wrong there and how to make it in proper way
Mr. TR deserves not just funny note from Papa's lawyers ( not because he can take part of Papa's pie , but because these poor "amps" are negative propaganda for Papa's work) , but also not just one lawsuit because his "amps" are jeopardy
I'm service tech my entire professional life ..... and that's just disgrace for our craft