The Christiansen "DG" 300B Amplifier Build Thread

[sceleratus]

Speakers.
I pulled the trigger on a pair of ZuAudio Soul speakers.
Their web site is overflowing with marketing speak, like no other I've seen.  I get skeptical when I see that.
 
What I liked is the 60 day return policy.  I wouldn't have that option with MLT's and such.
I also read some posts from owners on AudioKarma.  Not like an owner is going to bash his speakers.....
They are very efficient at 99dB/w/m and they are 8 ohm.   Of all the speakers I looked at none published a 2 - 200 watt range.
That makes m comfortable.
Lastly, I got a deal on a demo set.  I retained the return privilege.  (If only I had an amp.)
 

Soul Mk.II Quick Specs​

Height: 31.5” [80cm]
Footprint: 12.14 x 12.14” [30.8 x 30.8cm]
Weight: 42 pounds [19kg] each. 53 pounds [24kg] packaged
Bandwidth: 45 – 22kHz
Efficiency: 99 dB SPL 1W, 1m
Impedance: 8 ohm
Power Amp Range: 2 – 200 watt
Made In Ogden, Utah—U.S.A.​

 

[tomchr]

Technically, that's a 2-way speaker, but the tweeter only kicks in above 12 kHz. Most tweeters in 2-way systems kick in in the low kHz, so this Soul speaker should sound more like a full ranger than a 2-way speaker. What impresses me is that they were able to get a 10" driver to produce sound up to 12 kHz... It'll be interesting to hear your review.
 
I do agree on the marketing speek, though. "Old school rooted, yet state of the art". Mmm yeah.
 
99 dB/W/m is *sensitive*. You'll hear the grass grow with those speakers...
 
~Tom

 

[OJNeg]

  Technically, that's a 2-way speaker, but the tweeter only kicks in above 12 kHz. Most tweeters in 2-way systems kick in in the low kHz, so this Soul speaker should sound more like a full ranger than a 2-way speaker. What impresses me is that they were able to get a 10" driver to produce sound up to 12 kHz... It'll be interesting to hear your review.
 
I do agree on the marketing speek, though. "Old school rooted, yet state of the art". Mmm yeah.
 
99 dB/W/m is *sensitive*. You'll hear the grass grow with those speakers...
 
~Tom

 
I'm betting that's where the cone breakup is. Probably rolls off fast after that.

 

[tomchr]

 
I'm betting that's where the cone breakup is. Probably rolls off fast after that.

 
No doubt. That's why they have the tweeter taking over at that point. It's a coaxial driver...

It is possible to make larger drivers make noise at higher frequencies. Check out the Mark Audio Alpair 10P-A. I'm toying with the idea of building a MLTL full range speaker based on that driver. A quick check says I should be able to get down to about 28~30 Hz (-3 dB).
 
~Tom

 

[sceleratus]

MLT with the 10P
 
Bob Brines is a cool dude.

 

[tomchr]

Bob Brines is indeed cool. I've never met him, but from his posts he seems knowledgable and plugged in. His speakers use the metal cone version of the Alpair 10. I'd rather use the paper version.
 
~Tom

 

[sceleratus]

Not Good, and don't ask.

 

[Tjj226 Angel]

  Bob Brines is indeed cool. I've never met him, but from his posts he seems knowledgable and plugged in. His speakers use the metal cone version of the Alpair 10. I'd rather use the paper version.
 
~Tom

Nah, if you are going to build speakers, go with an altec 755 driver. 

 

[sceleratus]

Nah, if you are going to build speakers, go with an altec 755 driver. 

Will you quantify that?

 

[sceleratus]

Yesterday I joined the I blew up a board with a DMM probe club.
I guess there really is high voltage coarsing through the traces.
 
Silicon carnage:
 

 

[nikongod]

What were those things supposed to do, and how did they get busted?
Short to ground? 

 

[sceleratus]

  What were those things supposed to do, and how did they get busted?
Short to ground? 

 
 

 

[GrindingThud]

Wow, snappy!

Yesterday I joined the I blew up a board with a DMM probe club.
I guess there really is high voltage coarsing through the traces.

Silicon carnage:

 

[tomchr]

Welcome to high-energy circuits... Sucks with the blown components, though.
 
When I designed my 21st Century Maida Regulator, one of the goals was to make the circuit resistant to common issues such as loose connections in output tube sockets. A sparking connection puts some rather nasty high ∂i/∂t spikes (i.e. rapid change in current vs time) into the regulator circuit. So I torture tested the regulator with a light bulb load where I wiggled one of the bulbs. I exploded a few TO-247 packages before getting all the kinks out. The end result was a very rugged regulator!
 
Wear safety goggles!
 
~Tom

 

[randytsuch]

On my DMM probes, I have a set with heat shrink that covers most of the probe, leaving just the tip exposed.
 
I use these where there is a change to short the probes against other parts of the circuit.
 
Randy