Building an F1. Yes, your thinking I've gone plum loco. Maybe.
It's 2014 and I'm sure there are other great Pass amps. But I'm intrigued by the current source technology as it's well suited for full-range drivers. Tell me otherwise.
I'm looking at some 15-inch Audio Nirvana's. I'd like a Pass amp to go with it. So, kinda an issue, these are big drivers. But still sensitive. F1 only capable of 10w and really only half of that if I'm looking at minimal distortion. One of the specs that I look at when selecting drivers is the Qts. It's reasonably low at 0.34 which, together with the F1's high output impedance, should produce some nice bass. This is a good thing for full-range drivers. If the Qts was higher I may have gone with an F5 or voltage source type. Still, the output power of the F1 is poking my brain. Ouch! At the end of the day, me just needs awesome sound. Mmmmm
Your opinions and insight are appreciated. Next post coming soon regarding those dern JFETs.
It's 2014 and I'm sure there are other great Pass amps. But I'm intrigued by the current source technology as it's well suited for full-range drivers. Tell me otherwise.
I'm looking at some 15-inch Audio Nirvana's. I'd like a Pass amp to go with it. So, kinda an issue, these are big drivers. But still sensitive. F1 only capable of 10w and really only half of that if I'm looking at minimal distortion. One of the specs that I look at when selecting drivers is the Qts. It's reasonably low at 0.34 which, together with the F1's high output impedance, should produce some nice bass. This is a good thing for full-range drivers. If the Qts was higher I may have gone with an F5 or voltage source type. Still, the output power of the F1 is poking my brain. Ouch! At the end of the day, me just needs awesome sound. Mmmmm
Your opinions and insight are appreciated. Next post coming soon regarding those dern JFETs.
Current source amps are awesome, I'm in the progress of building me 4x F2J inspired amps ( or they were a long time ago 😉 )
10W is a lot though, and keep in mind that the F1 can output 10W into 16 ohms also.
10W is a lot though, and keep in mind that the F1 can output 10W into 16 ohms also.
Yes I know. 10W @ 5% THD
I tend to be a wee bit more conservative. Looking at the distortion vs power chart in the service manual, I'm seeing about 4.5W @ 1% THD.
I tend to be a wee bit more conservative. Looking at the distortion vs power chart in the service manual, I'm seeing about 4.5W @ 1% THD.
Alternate JFET
Moving on to those dern JFET's.
So this Semisouth SJEP120R100 is obsolete? I've spend the last week reading post after post and maybe I missed something, but could not find a replacement JFET mentioned. I've stumbled on the 6moons review of the J2 showing the 120R125. Most of everything else I read was that Semisouth went bye bye. No more. Am I wrong?
I need an alternate JFET to work with. Please advise.
Moving on to those dern JFET's.
So this Semisouth SJEP120R100 is obsolete? I've spend the last week reading post after post and maybe I missed something, but could not find a replacement JFET mentioned. I've stumbled on the 6moons review of the J2 showing the 120R125. Most of everything else I read was that Semisouth went bye bye. No more. Am I wrong?
I need an alternate JFET to work with. Please advise.
Considering an F2J to push some 1.4" compression drivers. Le'Cleach forwarded the idea that they lowered distortion in horn speakers. Believe he even showed evidence of the improvement on his TAD drivers.
I'm running my full range speakers with the ACA @ 5 watts... the F1 should be plenty.
Oh, and no, its not loco... my F2J build is still on the cards... just delayed a bit as the ACA has been great.
Oh, and no, its not loco... my F2J build is still on the cards... just delayed a bit as the ACA has been great.
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I'm driving an AN15 with a flea watt amplifier (1W to 2W perhaps) and it provides enough volume. However, my tube amplifier isn't the best, it was my first tube amp ever and I think the speaker can do better with an improved amplifier design.
http://www.diyaudio.com/forums/full-range/217893-bigun-audio-nirvana-super-15-a.html
@Bigun Thats a very interesting speaker build you did with the AN15. I'll probably be referring to your post when I start building mine.
I have a 2w Pass-inspired JFET differential amp, transformer biased. It gets pretty loud with Dave Merrill's DCA5.5 speakers.
what part number does what?
Do you mean what JFET is used or in total what components are needed to upgrade F1 -> F1J?
any enhanced mode semisouth
meaning - SJEP120R063 or SJEP120R085 or SJEP120R100 or SJEP120R125
contact Semisouthfan for anything available and , if you get them , ask here for further instructions
edit - being CCS biased , even depletion mode will work OK < so SJDP types are welcome , too
that's just broadening possible choice , so - grab cheapest ones you can snatch
meaning - SJEP120R063 or SJEP120R085 or SJEP120R100 or SJEP120R125
contact Semisouthfan for anything available and , if you get them , ask here for further instructions
edit - being CCS biased , even depletion mode will work OK < so SJDP types are welcome , too
that's just broadening possible choice , so - grab cheapest ones you can snatch
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