Hi,
I would like to build one of the First Watt DIY amplifiers to power my Ron Clarke Austin 126 Rear Loaded Horn speakers. The speakers are using the Fostex Fe126en drivers.
Please could someone point me in the direction of which of the First Watt offerings would be most suitable?
Thanks in advance for any help.
I would like to build one of the First Watt DIY amplifiers to power my Ron Clarke Austin 126 Rear Loaded Horn speakers. The speakers are using the Fostex Fe126en drivers.
Please could someone point me in the direction of which of the First Watt offerings would be most suitable?
Thanks in advance for any help.
Single driver full range I'd probably try one of the current source designs, F1, F1J, F2 or F2J.
https://www.firstwatt.com/f1.html
https://www.firstwatt.com/f1j.html
https://www.firstwatt.com/f2.html
https://www.firstwatt.com/f2j.html
May take some tweaking:
https://www.firstwatt.com/pdf/art_cs_amps.pdf
https://www.firstwatt.com/f1.html
https://www.firstwatt.com/f1j.html
https://www.firstwatt.com/f2.html
https://www.firstwatt.com/f2j.html
May take some tweaking:
https://www.firstwatt.com/pdf/art_cs_amps.pdf
Hi,
Thanks for the recommendations. Would you mind explaining why you chose these models over that of say the M2 please?
Kind regards.
Haha what a coincidence. I just built a pair of BK12M back-loaded horn enclosures which feature Fostex FE126En drivers. Planet10 in the thread on these cabinets says two things 1) they need 100+ hours to break in and get less shouty and harsh and 2) they like to be driven by an amp with a relatively low Zout / DF. I've preferentially been playing them with my ACA (DF =10) and my F3 clone (DF = 6).
Attachments
I would suggest F2 first, F1 next. The FExx6 drivers really want a highish Rout, at the low cost, easy to put together, a pair of ACA Bridged Mono.
Rout of the F2 is likey closest to best match. IIRC 4Ω, F1 is 40Ω, ACAmono is 1.6Ω.
dave
Rout of the F2 is likey closest to best match. IIRC 4Ω, F1 is 40Ω, ACAmono is 1.6Ω.
dave
Thanks for the response Dave. I have been looking into the F2 for the last few hours. 🙂
As the F2J is an improvement over the F2, would the F2J be a better option to build?
The other devices with a potentially lower distortion profile than the IRFP240 are the onsemi FQA19N20C. There's a test of them at the end of that thread. I poked around to see if any were available online and the only place I found was Aliexpress, and that vendor had pictures both of what looked like a genuine one and a potential copy. No thank you. But, an F2 built with these could be interesting.
JamesBW,
In case you haven't seem this, member Twitchie did a number of tests with different devices over a few pages starting here:
https://www.diyaudio.com/community/threads/diy-f2-clone.91168/page-31
The Cree part with the lowest distortion that Twitchie measured is still available (for example at digikey)
As for the Fairchild part, it's been discontinued for a number of years now and there are definitely fakes out there. So be careful if you want to pursue that. Another option may be to look at the current Onsemi (formerly Fairchild) offerings and find something that is close to the FQA19n20c. (If you're fearless, you might look into the FQP19n20C, which is very similar to the FQA19n20c, but in the smaller TO-220 package with a lower dissipation limit.)
In case you haven't seem this, member Twitchie did a number of tests with different devices over a few pages starting here:
https://www.diyaudio.com/community/threads/diy-f2-clone.91168/page-31
The Cree part with the lowest distortion that Twitchie measured is still available (for example at digikey)
As for the Fairchild part, it's been discontinued for a number of years now and there are definitely fakes out there. So be careful if you want to pursue that. Another option may be to look at the current Onsemi (formerly Fairchild) offerings and find something that is close to the FQA19n20c. (If you're fearless, you might look into the FQP19n20C, which is very similar to the FQA19n20c, but in the smaller TO-220 package with a lower dissipation limit.)
JamesBW,
This is the post of Twitchie's test using FQA19n20C:
https://www.diyaudio.com/community/threads/diy-f2-clone.91168/page-32#post-6559827 (Post #622)
This is the post of Twitchie's test using FQA19n20C:
https://www.diyaudio.com/community/threads/diy-f2-clone.91168/page-32#post-6559827 (Post #622)
