Thanks.
The second one has yet to be built, but I have all the parts ready. The second build is always a bit easier due to the experience gained from the first.
My main speakers are Infinity RSIIb's...see picture below. I completely rebuilt them a couple years ago; the crossovers are now in those oak veneered boxes behind the speakers. Currently they are powered by class D 500WPC monoblocks, it should make for an interesting comparison...
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That's a possibility. I was also thinking of a metal screen like a soffit vent type of item. There are already small holes in the sides of the cylinder and thumbscrews that hold it to the teflon tube base to secure the cylinder.
I have some things to do today so my experimentation time is limited, but I'll do some listening and report back ASAP.
I am a Solid State diy'er, but must admit that this is a super duper project. I was following it from the beginning.
Those amp's must have cost you a small fortune when looking at the amount of iron coming from 30km's away from me and the amount of parts in this amp!
The more I see those tubes, the more I like to use them once! For now I try to not get in love whit them, it would cost me annother human lifetime
Congratulations whit this build.
Those amp's must have cost you a small fortune when looking at the amount of iron coming from 30km's away from me and the amount of parts in this amp!
The more I see those tubes, the more I like to use them once! For now I try to not get in love whit them, it would cost me annother human lifetime
Congratulations whit this build.
So, are you going to have the big-ol' 500W "D' job run the bottom half & the tubes run the ribbons??
How about a matching pair of Brass antique vent-tops??? with a modern look?
Think of something wild, take it to somebody who has a milling machine....brass doesn't hurt bits...so they shouldn't charge you too much.
___________________________________________________Rick.............
How about a matching pair of Brass antique vent-tops??? with a modern look?
Think of something wild, take it to somebody who has a milling machine....brass doesn't hurt bits...so they shouldn't charge you too much.
___________________________________________________Rick.............
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One more thing I need to work out. The inrush current on the 833 circuit is still pretty high, even with the soft start module in place. If I set the 833 bias to 253V (equivalent to about 80mA 833 current), the 833 starts up fine, then I can manually adjust the bias downward to 245V or so to increase the plate current to 140-160mA with no issues. If, however, I leave the bias set at 245V and try to start up the 833, I blow an 8A or even 10A slow blow mains fuse as soon as the soft start period (1 second) is over.
I think I need to adjust a cap value on the soft start board to extend the period of time for the soft start to be a bit longer, or maybe decrease the limiting resistor value from 68 ohms to allow a little more current to flow during the soft start period so it's not such a big rush once the soft start is over. Until I work that out, though, I do have a workaround via the manual bias adjustment even if it is a little cumbersome.
I think I need to adjust a cap value on the soft start board to extend the period of time for the soft start to be a bit longer, or maybe decrease the limiting resistor value from 68 ohms to allow a little more current to flow during the soft start period so it's not such a big rush once the soft start is over. Until I work that out, though, I do have a workaround via the manual bias adjustment even if it is a little cumbersome.
No, my experience to date with bi-amping has sounded to me like listening to two different amps. If at all possible, I'd like to run the whole speaker with one amp. The impedance curve at the low end isn't bad on those speakers - it's 10kHz and up where they drop to 2ohms or so.
OK, I managed to do a little listening today. For this quick session I just used the old Rectilinear XI speakers on my workbench. They are nominal 8ohms, and the amp 4ohm tap is the only one hooked up, so that's what I used.
First of all, the amp is dead silent with no signal input, no detectable hum whatsoever, which agrees with what I saw on the scope. Good, I hate hum.
I then played the Blues Deluxe CD by Joe Bonamassa, through the preamp outputs of my shop receiver. First impressions:
Bass is full, and as deep as the old Rectilinears can go.
Treble is clean, but not harsh.
Volume-wise, 10-11 o'clock on the volume knob was loud, loud enough for my wife to tell me to turn it down (she was on the floor directly above the workshop...) ;-).
Of course, these observations are limited by the old speakers, cheap CD player, and receiver preamp, but it was not bad at all!
Chassis temp stayed around 42-45C, so no heat issues yet, although the session was only 15 minutes long.
First of all, the amp is dead silent with no signal input, no detectable hum whatsoever, which agrees with what I saw on the scope. Good, I hate hum.
I then played the Blues Deluxe CD by Joe Bonamassa, through the preamp outputs of my shop receiver. First impressions:
Bass is full, and as deep as the old Rectilinears can go.
Treble is clean, but not harsh.
Volume-wise, 10-11 o'clock on the volume knob was loud, loud enough for my wife to tell me to turn it down (she was on the floor directly above the workshop...) ;-).
Of course, these observations are limited by the old speakers, cheap CD player, and receiver preamp, but it was not bad at all!
Chassis temp stayed around 42-45C, so no heat issues yet, although the session was only 15 minutes long.
So Magz how does your wife like you too new babies in the family, lol. Especially since you got to give birth to the this time, lol.
Those thing are a real beauty. I beat your as proud as a new dad too, well almost. And you don't have the stinky diapers to change.
I hope you get many a year of fun out of them. I wish I still lived in Massachusetts, I'd have to take a weekend trip to New Jersey to check them out.
Enjoy brother, enjoy.
Nick
Those thing are a real beauty. I beat your as proud as a new dad too, well almost. And you don't have the stinky diapers to change.
I hope you get many a year of fun out of them. I wish I still lived in Massachusetts, I'd have to take a weekend trip to New Jersey to check them out.
Enjoy brother, enjoy.
Nick
I strongly suspect that the 68ohm resistor in the NewClassD soft starts is sized for European 230V systems. Most references I can find recommend more like 20-30ohm for 120V systems, so I've ordered some 22ohm, 15W resistors to swap in, and expect that will alleviate the inrush issue on the 833. I'll report back once I get them.