Not yet. I did some initial bench work (enough to eliminate pentodes as cathode follower candidates, but validate them for gyrators), but then had my free time taken up by a two magazine articles which I had promised. Hopefully, I'll be able to refocus. 
The real problem is that there's so much great live music around here, I don't spend much time listening to my stereo.
The real problem is that there's so much great live music around here, I don't spend much time listening to my stereo.
Never been to Austin, but I've heard it's probably the best music scene in the US. Chapel Hill, NC is similar on a much smaller scale. No reason to stay home.
Columbus Ohio had a surprisingly good jazz scene there. I could roll a couple buildings down and catch something worthwhile any night.
I can't figure out D.C. Lots of Jazz and Classical it seems, not much else interesting, and too hard to get to or too expensive. Lot's of time for amps here.
Columbus Ohio had a surprisingly good jazz scene there. I could roll a couple buildings down and catch something worthwhile any night.
I can't figure out D.C. Lots of Jazz and Classical it seems, not much else interesting, and too hard to get to or too expensive. Lot's of time for amps here.
Yeah, I used to hang at a couple of the clubs in DC back in my college days. Great shows, but really, really expensive. There was a place in Georgetown that usually booked trios and quartets. One weekend, they wedged Sun Ra's Arkestra into a space about double the size of my living room. Spectacular! It took all of my discretionary income for that month but it was worth it.
Here, if I have to pay $10 cover, that's considered expensive. Most of the better musicians can be hired very reasonably for a house concert- if we do another audio get-together here, I'll get a few acts to put our stereos to shame.
Here, if I have to pay $10 cover, that's considered expensive. Most of the better musicians can be hired very reasonably for a house concert- if we do another audio get-together here, I'll get a few acts to put our stereos to shame.
That was done at the recent Capitol Audiofest and it ruled. Loud, too! Cymbals are 20" tweeters.
In the photo below L-R: Nasar Abadey on drums, Antonio Parker on alto sax, James King on bass, Allyn Johnson on electric piano and Gary Gill (the event organizer) sitting in on trombone.
In the photo below L-R: Nasar Abadey on drums, Antonio Parker on alto sax, James King on bass, Allyn Johnson on electric piano and Gary Gill (the event organizer) sitting in on trombone.
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I was tempted to go to the Capitol Audiofest since it was real close by. I figured it would be safer (for my wallet) to stay home. No reason to tease myself.
I'm still kicking myself for not attending the Live vs Real event that happened right down the street from me.
I'm still kicking myself for not attending the Live vs Real event that happened right down the street from me.
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DC has been mostly miss for music since the demise of Charlie Byrd's place (and King of France a wee bit to the north). Saw Joe Pass and George Shearing there one time. Sat at the bar with Joe during the break. I drank beer, he drank pop. Brought in my guitar for an autograph and Joe jumped back completely aghast. He thought I was going to play for him...
They were not loud, and they rocked. Maybe 60 people in the whole place.
Birchmere plays both kinds of music (country and western), plus the occasional REALLY over the hill act. During one break, they changed Leon Redbone's diapler, while I took a nap. They must have had some gravity altering machine to float Dr. John on and off stage... Professional job, though. Could not see the puppet strings on his fingers. Thought he was really playing. Ugh.
Cafe Lautrec in Adams Morgan used to put on a nice show, but dropping $20 at the door for your 1st two carefully measured drinks somehow spoiled it until the bartender tap danced on the bar at closing.
Vegas Lounge used to rock, but now a complete bust.
DC Blues Festival had Pine Top Perkins a few years back. 100 years old or so. Coughed into the mike "doin' the best I can". Unfortunately, the best act on stage.
Unknown Hinson was here. Cool if can tolerate metal on a Tele for more than 5 seconds, or care for jokes about Liquid Chicken (doesn't promote a firm movement). Ugh.
These days it is the balalaika orchestra or stay home. Darn. DC used to be cool. Now it is not cool at all.
Sorry. Touched nerve.
They were not loud, and they rocked. Maybe 60 people in the whole place.
Birchmere plays both kinds of music (country and western), plus the occasional REALLY over the hill act. During one break, they changed Leon Redbone's diapler, while I took a nap. They must have had some gravity altering machine to float Dr. John on and off stage... Professional job, though. Could not see the puppet strings on his fingers. Thought he was really playing. Ugh.
Cafe Lautrec in Adams Morgan used to put on a nice show, but dropping $20 at the door for your 1st two carefully measured drinks somehow spoiled it until the bartender tap danced on the bar at closing.
Vegas Lounge used to rock, but now a complete bust.
DC Blues Festival had Pine Top Perkins a few years back. 100 years old or so. Coughed into the mike "doin' the best I can". Unfortunately, the best act on stage.
Unknown Hinson was here. Cool if can tolerate metal on a Tele for more than 5 seconds, or care for jokes about Liquid Chicken (doesn't promote a firm movement). Ugh.
These days it is the balalaika orchestra or stay home. Darn. DC used to be cool. Now it is not cool at all.
Sorry. Touched nerve.
And, while my humor is still sour, that would be XLII. Life, the universe, and correct use of Roman numerals, unless there is a joke in there I don't get.
I yield back the rest of my time to the regularly programmed schedule on x-overs.
Sorry, dude. DC used to be great- so was Baltimore in the days of the Famous Ballroom and Ethel's. There was another little club owned by Harry Gladding (the car dealer), the Bandstand, that always had GREAT after-hours shows following the weekly Left Bank Jazz Society concert. Ah, well, life moves on. And so did I.
Now it's the Cactus Cafe, The Ghost Room, Whip In, Flipnotics, the Saxon, the Elephant Room... too much good music, not enough time. High class problem.
Now it's the Cactus Cafe, The Ghost Room, Whip In, Flipnotics, the Saxon, the Elephant Room... too much good music, not enough time. High class problem.
When I think Baltimore, I think Hammer Jack's. 3 levels, 7 bars, 3 bands, and intoxicated "ladies" from see to shining see. A generous pour, and the biker chicks started to look fine, fine, fine, if a bit smelly. Parking for 10,000 Harleys. Size of a square city block. Converted some old factory, I recall.
If you wanted to speak to your "lady", just grab her by the hand and walk for 5 or 10 minutes to a part where it wasn't so loud.
I feel old. Perhaps, I should move on too.
Pete,
IIRC from reading your write up about your original tube active Sallen Key crossover you were not pleased with the noise performance. Seems like SK filters like OpAmps with lots of open loop gain.
Sy,
If you will, what are the design goals? Number of tubes and all. Tell us more?
In my HiFi mind I am a little, schizoid, dual personality. Single driver OB or headphones I like and build tube stuff. Then there are Linkwitz style 3 way dipoles with digital speaker management (Behringer) and SS power amplifiers. (Rane 900 watt 6-pack). I would like to replace the Behringer with tubes.
DT
Just for fun
IIRC from reading your write up about your original tube active Sallen Key crossover you were not pleased with the noise performance. Seems like SK filters like OpAmps with lots of open loop gain.
Sy,
If you will, what are the design goals? Number of tubes and all. Tell us more?
In my HiFi mind I am a little, schizoid, dual personality. Single driver OB or headphones I like and build tube stuff. Then there are Linkwitz style 3 way dipoles with digital speaker management (Behringer) and SS power amplifiers. (Rane 900 watt 6-pack). I would like to replace the Behringer with tubes.
DT
Just for fun
Per channel, per division (i.e., bass, treble), two or three cathode followers, two gyrators. 2nd or 4th order, designable for any reasonable Q (<2). Low distortion, low noise, high stability. Take a look at the Acheron design on my website (tip of the hat to Wintermute who found a few calculation mistakes in my writeup, which I'll fix one of these days) for a general outline- I'm substituting pentode CFs for the gyrators, triode CFs will be about the same.
Thanks Sy, I have a complete spice model (including the triodes) if you would like me to upload it here (I think it is on my home computer). It isn't exactly the same as your published schematic, but I think there is only one component value different, which I changed to get the curve to look right (to me).
Tony.
Tony.
Ok here it is for anyone who is interested. This is an LTSpice model of SY's acheron. I don't know how good the model of the triode is but the simulation seems to work
The component change is the 200K resistor which has been changed to a 4Meg resistor, without this change the simulation does not produce anything remotely like a butterworth roll off. The passive network is there to do comparisons to an ideal passive CL circuit.
In the attached pic the blue trace is the passive circuit and the green trace is the output from the acheron.
Increasing the the value of the blocking cap (after the active inductor) to 15n or 22n makes the curve match better down lower but it is not as good a match at the corner freq. The value SY chose of 10n seems to be the best compromise.
I also used opa134's instead of tl072's mainly because I already had the model for them for LT spice. The attached zip file has (I think) everything in it that you will need to get the model running, make sure you read the readme file as it has some definitions in it that need to be added to the standard.dio file.
Note I'm not a tube guy I was interested in the gyrator part of SY's circuit, which I came across in the B1 active crossover thread, and decided to model it to get a better understanding of how it worked That eventually lead me to my own design which unfortunately has still only been simmed at this stage.
Tony.
The component change is the 200K resistor which has been changed to a 4Meg resistor, without this change the simulation does not produce anything remotely like a butterworth roll off. The passive network is there to do comparisons to an ideal passive CL circuit.
In the attached pic the blue trace is the passive circuit and the green trace is the output from the acheron.
Increasing the the value of the blocking cap (after the active inductor) to 15n or 22n makes the curve match better down lower but it is not as good a match at the corner freq. The value SY chose of 10n seems to be the best compromise.
I also used opa134's instead of tl072's mainly because I already had the model for them for LT spice. The attached zip file has (I think) everything in it that you will need to get the model running, make sure you read the readme file as it has some definitions in it that need to be added to the standard.dio file.
Note I'm not a tube guy
I was interested in the gyrator part of SY's circuit, which I came across in the B1 active crossover thread, and decided to model it to get a better understanding of how it worked That eventually lead me to my own design which unfortunately has still only been simmed at this stage. Tony.
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hehehe
I used to have fun trying to find tubes for my Pye Pedigree TV (I believe the first Australian built B&W set) I wonder if it is still under my parents house
I really took a dislike to tubes when I thought that a tube car radio was safe to handle because it was only running off 12V
I got a very nasty belt off it and haven't touched any tube gear since... that was about 26 years ago....So you might guess that constantly battling to find replacements for blown tubes, and then one biting me sort of tainted my view of them
Tony.
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