Friday, December 30, 2011

System Two Update

Yet another system two update. This time its another speaker again. Well, I do not know what made me to built these speakers, perhaps I wanted to imitate the look of Legacy Whisper, just kidding. It only remotely resembles Whisper. Anyway, it started long time ago when I got 2" Dayton domes brand new never used very cheaply on ebay, so I started looking for an application. I have seen HiVi ribbons on sale, so it was only a matter of finishing the lower mids section. I selected Dayton 4" midwoofers RS125. Crossovers were optimized using Holm Impulse program based on real measurements. Panels are open baffle, what else, working from 150Hz up. Woofers is still the same, 15" Jamo in closed box.
The system is biamplified using active crossover, has 31 band digital eq and tube amp for mids/heights and solid state for woofers. Signal sources are the same as before, Cambridge Audio CP player (dual Wolfson), SAE FM tuner, Technics SP25 with ATOC9 cart, some Onkyo Integra deck and preamp (used only for signal switching and RIAA), and digital tape player. System could use better amp, I am working on it.

Thursday, December 29, 2011

CBT array update


I added tweeters to the CBT line arrays. Even those NS3 Aura's are "fullrange", their response drops after 10kHz. They need significant eq in order to sound good. Tweeters are needed. Eighteen tweeters were wired in three sections of six to give 16 ohms, to match the Aura's. Arrays sound much better now, almost no need for eq. Last picture might be confusing a little, just to clarify, there are two systems. Line arrays are powered by two older silver JVC SuperA AX1 and AX2 amps, it's bi amplified with active crossover at 170Hz and 2x15" black subwoofer in the back. Other system is something else, Betsy WOW MTM with Selenium horn tweeters, excellent sounding open baffle, with two 15" woofers handling the bass. Second system is powered by JVC receiver, SuperA as well. By the way, these JVC components are under appreciated gems, they sound gorgeous. JVC did great job with their SuperA circuit. Their CD players are excellent also, once their output stage (3 dual OPA's) is bypassed by simple tube buffer. I lampized some and they are excellent sounding CD players. But that is another story.

6N11 Linestage

I just finished new line stage, it's SRPP with 6N11. I bought this kit on ebay for $35 plus shipping. The line preamp has four inputs with nice japanese relays for switching and one output. Two transformers are used, one for preamp and one for signal switching. The line stage is absolutely quiet, no hiss, no hum. It sounds excellent.

Wednesday, December 28, 2011

CBT Line array

Don Keele's constant beamwidth transducer...or something like that.
I got plenty of small tweeters, Onkyo tweeters sale, box of 200 tweeters for $20. I got 100 small 3" fullrange drivers Aura NS3 for $1.50 each...so what is one to do? Line array! Well, I built line arrays before and they can do amazing things, but this time I was about to built something totally different. Here are some pictures from the built, its still work in progress.
It was a bit of a challenge, since the only tools I have are drill and jigsaw. Plus I used smaller pieces of plywood, so I had to glue larger pieces together. Inspite of the challenge, I enjoyed the build. Currently the arrays have only 3" fullrange drivers. Tweeters come later. I could not wait. All the fullrange are wired equally, no shading. I have my reasons for it. 16 small 3" fullrange units, each 16 ohm is wired in 4 sections of four giving nice 16 ohm output impedance. Easy to drive with any amp.