"Please allow me to introduce myself"...

[Adolf Corkscrew]

"I'm a man of no wealth, nor fame".

Born in Finland, and still living and studying here, majoring in electronics. I've probably had the Hi-Fi bug since I was a little kid, maybe inheritance from my father. I first got into tubes and DIY when I was 13 or 14. Only back then my financiers (read parents) didn't see it as a profitable venture. After some years and some commercial Hi-Fi and maybe even almost High End products, I've returned to DIY for solace. Bad sound is ubiquitous, and must be fought, and none shall abandon the front.

I joined this forum for advice when in a dead end, and also hoping I could make a contribution.

I've built some tubed gear during the years. I have a couple of KT88 monoblocks, an ECC99-powered preamp, a DIY phono stage, an E55L spud amp I built as a joke and a DAC with a tube output stage. The last two are my own designs. The former ones I've modified from existing schematics. Speakers are modified from M. J. Kings passive open baffle design (FE108E Sigma + Beta 15A, passive series crossover).

Oh, and don't be confused with my pseudonym. It's something dating back when I designed what is probably the most annoying basic program in the universe. Just something saying out loud, how crooked my sense of humour might sometimes be.

[Rodeodave]

Sounds interesting. Welcome to the forum!

The OB speakers sound tempting. Would you share the design?

[Adolf Corkscrew]

Originally Posted by Rodeodave

Sounds interesting. Welcome to the forum!

The OB speakers sound tempting. Would you share the design?

Thank you.

And why not share, since they're still essentially the "King design". The measures are still straight from the King paper, http://www.quarter-wave.com/OBs/OB_Design.pdf. I started with the original design, excluding the FR driver, which I substituted with the FE108E Sigmas. It was nice, but didn't integrate really well. I went through some crossovers, until I finally decided to ditch the Eminence Alpha and substituted it with a Beta instead, and went for a second order bessel crossover at 250Hz. I haven't measured the results, since I don't have the equipment, but now it sounds more balanced. The beta seems to go lower (subjectively) than the alpha, and is more punchy.

[Rodeodave]

Thanks, I'm asking because I too have the FE108E sigmas, but in the recommended BLH. There are some other designs I'd like to try one day, I found at least one other OB design, then there's the Swan of course, and there also is one spiral horn design. But OB seems to be en vogue and a little less effort that the others
I'm thinking about bi-amping with a active crossover based on the Xenover Ver. 2.0 Article By Grey Rollins.
We'll see...
Enjoy your stay!