The Christiansen "DG" 300B Amplifier Build Thread
Jul 19, 2013 at 6:14 PM Post #271 of 655
A am in tears......
 
OMG !
 
It Works
 
 It was a huge fight.  Totally freaked.
 
First song:   James Taylor  "Country Road"   flac  HD Tracks.
 
EDIT...
What a difference the Mundorf Silver Oil caps made......  Wow !
 
Jul 19, 2013 at 7:40 PM Post #274 of 655
[size=medium]What a struggle…..[/size][size=medium][/size]
[size=medium]Easy to find…..  XLR's OPT were rolled.[/size][size=medium][/size]
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[size=medium]No most normal people would say  "Fine switch the OPT wires… in line"[/size][size=medium][/size]
[size=medium]No not Bozo.   I desoldered these stinking Cardas Jacks. [/size][size=medium][/size]
[size=medium]Mid way through… and I'm not sure what I was doing a pin comes out.[/size][size=medium][/size]
[size=medium]"He, looks modular, I'lll pull all of them"[/size][size=medium][/size]
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[size=medium]They aren't modular.[/size][size=medium][/size]
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[size=medium]I am certain that they have an accessory plug that the guy I bought them from didn't tell me about.[/size][size=medium][/size]
[size=medium]Because they were a bitch to solder.  Didn't matter[/size][size=medium][/size]
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[size=medium]Now it's a good thing I had a set of locking Neutrik's[/size][size=medium][/size]
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[size=medium]Except, they aren't round.  They have protrusions for the locking mechanism. [/size][size=medium][/size]
[size=medium]Off to the garaged and the grinder.  Yes grinder.  As in sparks and metallic dust.[/size][size=medium][/size]
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[size=medium]They fit.  The part the covers the locking mechanism is aluminum foil thin…. but they work.[/size][size=medium][/size]
[size=medium]Next the hole were off just a tad.  I splintered some maple and filled the holes.[/size][size=medium][/size]
[size=medium]Next used a square and drilled the pilot holes.   Made some black screws withe a sharpie…[/size][size=medium][/size]
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[size=medium]Except they are crooked… a tiny bit… but it drives me nutz.  [/size][size=medium][/size]
[size=medium]I will fix them later.[/size][size=medium][/size]
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[size=medium]The good news is I like the black sockets much better then the cheesy gold plated Cardas set.[/size][size=medium][/size]
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[size=medium]More good news.  The Mundorf caps made a huge difference musically.[/size][size=medium][/size]
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[size=medium]What a blasted fight.  I'm drained.  At least I have music to listen to.[/size]
 
Jul 20, 2013 at 10:42 AM Post #277 of 655
Quote:
Congratulations sceleratus, your amp looks wonderful!
 
This thread has inspired me to get off my backside and get mine done.

+1
This project inspired me to start a DHT amp.  I had been thinking about it for a little while, this gave me a push to really get it started.
 
And I am lucky enough to live in LA, and am going to the head fi meet today to check this puppy out. 
biggrin.gif

 
Randy
 
Jul 21, 2013 at 4:39 PM Post #283 of 655
Many Thanks to @randytsuch for loaning me his Electro Harmonix 300Bs :)
There is a substantial difference between them and the JJ's
 
Jul 23, 2013 at 10:10 AM Post #284 of 655
Which ones did you like the best, the JJ's or the Electro Harmonex? 
Also, did you fix the hiss/fuzz sound?
Making a little progress on mine.  Have the main power supply board and the Maida boards done but not tested.  Parts for the filament boards are on order.
 
jIM
 
Jul 24, 2013 at 1:02 AM Post #285 of 655
I tried the JJ and the Full Music 300B/n mesh plate. The Full Music are really nice! JJs tend to be a bit 'edgy', the Full Music sound really smooth and natural to my ears. In end-to-end measurements (i.e. measuring the speaker output with a microphone rather than the amp output), I also noticed differences in the distribution of harmonics. Specifically, the Full Music tended to be dominated by 2nd harmonic, whereas, the harmonic structure of the JJ tubes varied more with frequency - sometimes the 3rd harmonic being higher in magnitude than the 2nd.
 
The Full Music tubes tend to run around $300/pair on [THAT AUCTION SITE]. The pair I had went back to the vendor, however. One of the tubes had issues with hot spots. Even at 390 V, 65 mA bias the plate on one of the tubes would develop cherry red spots. At 70 mA the spots were quite red, and the tube seemed to want to run away thermally. So be a bit careful and order from someone with a return policy.
 
~Tom
 

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