Welcome!

This is my webpage, where I hope to document whatever random audio-related projects I have going on.

Feel free to email me if you have any questions/ comments about content, or if you've done something similar and would like to comment on your findings.

What’s New and Changed

[19 Oct 10] Following up on my earlier experiments, I've stuck with the 4xEminence Kappa-12A to cover the bass region. But, instead of a passive crossover, I'm using an active one. The active crossover is just a couple of buffers plus a 2nd-order Butterworth low-pass filter and taps the signal from the binding posts of the main amplifer (still the 2A3 PP amp at this point - still need to get a page of its own up on the website). Rather than EQ'ing the low end actively, I'm using series resistance on the output of the (sub)woofer amplifier to raise the Qts of the 4xEminence drivers. Despite wasting a bunch of power in the series resistors, it's working very well. At the moment, it's still mono-only but I have some lower-Fs low-Qts drivers on the way. Once I confirm that they'll do the job and have a stereo pair constructed, I'll post a comprehensive update.

[22 Jan 10] A bit of a detour with my open baffle speakers... I built a test baffle to see if I could pull together an honestly fullrange 2.5way and consequently ditch the separate (sub)woofers. The lineup is: AH!1000+BeymaCP380M, 1xToneTubby 12" AlNiCo, 4xEminence Kappa-12A. I was hoping for a legitimate -3dB of 45Hz while maintaining 98dB/1W, and while it didn't work out quite the way I planned it was still a valuable exercise. I've posted an update here.

[01 Oct 09] I finally 'finished' the 2A3 push-pull amplifier I've been working on. Here is a schematic, there is a picture of the signal chasis (one channel), and this is a picture of the power supply for one channel. It's a pretty straightforward design: input transformer-buffered volume control (Penny&Giles RF11 in this instance), 6EW7 twin triode doing both input and driver duty with the little triode DC-coupled to the big triode, MQ autoformer as phase splitter, and 2A3 parafeed PP finals, with cathode biasing all around. The DC side of things is full-wave rectification with 6CJ3 TV damper diodes into a choke-input filter. Doesn't get much simpler than this. Results are preliminary, but suffice to say it's a much different amplifier than the 27 preamp/ 56->45 amp combination.

[29 May 09] Seriously, this time I really mean it; I'm absolutely, positively finished with the speakers. Scope out the latest crossover here. I've got a push-pull 2A3 amplifer in pieces strewn across the dining room table...

[20 Apr 09] Another leap forward on my speaker project. In fact, as far as I'm concerned, except for cosmetic issues they're done. You can check out the update on the TT12 page. I've got a push-pull 2A3 amplifer project up next.

[07 Jan 09] My speaker project, a combination of large diameter midbass drivers on an open baffle plus horn & compression driver, has seen some progress as of late. I switched driver compliment, from the vintage Jensen A12 & Altec 802-8D to current production ToneTubby 12" AlNiCo & Beyma CP380M. The venture has come a long way, but I still need to figure out something for sub-120hz. Here is my report to date.

[18 Apr 08] Added a reclocker to my DAC, using Guido's board and a reclocker board I had done at ExpressPCB based on carlosfm's board shown here. Here's a picture of where it stands currently. To say the least, I'm pretty happy with how it's shaping up. I've gone ahead and put my discussion of the 'completed' DAC on my 'Source' page here -- hopefully, I'll build a nice case for it sometime this summer. And, lastly, I updated my 'Current System' page.

[29 Jan 08] A speaker odyssey begins here... Jensen A12 12" field coil drivers on an open baffle plus an Altec 802-8D 1" compression driver/ 1000hz conical horn combination.

[09 Jan 08] I've just finished a PCM2707 → TDA1541A DAC using this board in conjunction with that board; I bought a board here in order to put together the 12Vdc supply needed by the USB receiver board. The build went very smoothly, all the PS voltages were right on, and the DAC fired right up withough smoke or flames. Further, it sounds wonderful from the start. You can see my build here. Note that I've left room for reclocking of some sort... I'll try to put a page together sooner rather than later.

[18 Dec 07] So, I finally got around to putting a page together on my 56 → 45 amplifier. Also, I converted my 11BM8 pushpull amp into a transconductance amp of sorts; the experiement is discussed here. And, lastly, I updated my 'Current System' page.

[26 Sept 07] I finished a 56 → 45 RC-coupled parafeed SE amp recently. It turned out very nice, but I need to take some pictures before I can post a page; stay tuned. In the meantime, I've scratched out a schematic that you can find here.

[16 Aug 07] Well, this webpage, for one. As I go along, hopefully I'll note progress made here, just to let you know if there's anything new since last you swung by.

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