Wednesday, February 8, 2012

April 2009 Bottleneck meet

We held out meeting at Steve's place in Stirling, VA. Since only 6 people turned up, we were able to spread out and relax without having to swap around seating positions etc. Fortunately, we had plenty of gear to listen to. This first picture shows Steve's new bay window which really opened up the room. The box at the back is a Foreplay with a remote volume control. In front are Paramours if I remember correctly.
Next is a chip amp that we sampled later in the day.
Then follows my 5894 push pull amp with 5687 drivers (LM317 in the tail). The output transformers are Websters given to me some years back by John Hogan after he came to one of our meets. It takes 10 -15 minutes before these tubes are ready to stabilize and about 30 minutes before the amp starts to sound half decent. I will probably rebuild them with a higher voltage than the 300 I used just to get my feet wet with them. You can see through them because I use polycarbonate. The power supply is separate.
Next is another gain clone chip amp that we played later in the day. What a beautiful layout, just a bit more room than mark's teapot housing from a few years back.
On to my John Swenson transconductance line stage. The design uses a slightly modifed Gary Pimm CCS. Again, I use polycarbonate and incidently, I used GOOP to glue the motor run caps and sundry other parts to the polycarbonate. The stuff works.
Next is the DAC of the day, in this case the boards used in the Lampizator. As I remember, David had replaced the caps with Oscons and the op amp with the recommended LM4562 ( I may have the wrong opamp) .We were all very impressed by this DAC and at under $100, even I will probably try one.
We used this Foreplay 3 (stock) for quite a while and we will probably use it in the 6V6 competion next year.
On to the speakers. First we have the Stomberg Carlsons in a corner cabinet. They don't have much bass but they are very pleasant listening and would be ideal in your beach shack. Next to them in the tall cabinet are the Tangband speakers we heard at the last meet. They didn't do as well this time and I can understand why Steve prefers his Seas speakers, at least in this room. In the bottom left is one of the Jordans.
On the right we have the Half Changs with the cheap full range BUF Pioneer speaker and a cheap Dayton tweeter. These did very well with a surprising amount of bass, but the mid range was no where near as good as the little Jordans.
Next are the Econowaves with a JBL LE14A for the bass and Selenium D220 driver. We currently plan to use these for the 6V6 competition.
The crossover for the Econowave.
An finally the crossovers for the Jordans / ribbon tweeters. Unfortunately, we didn't get to really hear them because one of the speakers was turned upside down and the mistake cause the bass to go to the  tweeter. Poor ribbon.

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