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Author Topic: Designing and building my own tube amp...  (Read 2807 times)

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dBel84

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Re: Designing and building my own tube amp...
« Reply #10 on: September 23, 2012, 06:58:43 PM »
thought I might be able to dig out a cool tutorial I had for getting started with tubes - sadly it has been lost in all the pc transfers I have had over the years but I will keep looking for it. Tubecad is one way to try and understand design and parts choice but sometimes Broskie gets lost in his own thoughts. Pete Millet has an incredible archive of old books on tube and design. Headwize has a few tutorial driven projects too.

I was going to suggest a kit too but as you have built the crack and not gained the sort of experience that you were hoping for, it really comes down to experimentation.

I think the important thing would be to read about different tubes of design, WCF, SRPP etc and then decide what you want to play with

for your experimentation, I would recommend these sockets  -  not good for the finished amp but it will allow you to breadboard easily.



they can be found at many places but a quick google search found the one above at PE http://www.parts-express.com/pe/showdetl.cfm?Partnumber=075-166&utm_source=googleps


AC wrote this cool paper on WCF for headphones - makes for good reading.
http://www.cavalliaudio.com/diy/docs/WCFOptimization.pdf

If you have an idea of stuff you might need, I am happy to raid my parts box , you could probably build a dozen amps from the bits lying about.

..dB


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maverickronin

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Re: Designing and building my own tube amp...
« Reply #11 on: September 24, 2012, 02:08:23 AM »
The Crack's instructions are pretty much just "solder part A to terminal 3" an so on.  There's no schematic (presumably because they're worried about someone 'stealing' the design) and it doesn't really tell you what any of the parts are there for or what they do.

I was already planing to make my own version of that kind of socket you pictured by attaching a normal socket to turret board or something and running small jumper wires to some terminals.  Then I can disassemble them later if I need to.

As for parts, I don't have much of anything yet.  I want to keep the Crack in one piece to either sell or mod later if I learn something interesting from this messing around.  The only potentially useful loose parts I have are a bunch of 250V resistors, a bag of random diodes that might have something useful, and several different tubes from the 12AU7, 6922, and 6080 families.  I was thinking that I should just get the power supplies I need to run those tubes along with an assortment of resistors and caps to string them all together and then just try different stuff.

Thanks for the WCF link.  It looks interesting.
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n3rdling

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Re: Designing and building my own tube amp...
« Reply #12 on: September 24, 2012, 04:22:29 AM »
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dBel84

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Re: Designing and building my own tube amp...
« Reply #13 on: September 24, 2012, 04:28:45 PM »
OOOh , when did they do this? I was always tempted by the jonokuchi

Based on the tubes ( 6922 ) , you might be good stating off with something like the Morgan Jones take on the Ear max

http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=cmoy5_prj.htm

..dB

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maverickronin

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Re: Designing and building my own tube amp...
« Reply #14 on: September 24, 2012, 08:41:35 PM »
Quote from: n3rdling on September 24, 2012, 04:22:29 AM
http://www.edcorusa.com/

Sweet!  Just what I needed.  Thank you.

Quote from: dBel84 on September 24, 2012, 04:28:45 PM
Based on the tubes ( 6922 ) , you might be good stating off with something like the Morgan Jones take on the Ear max

http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=cmoy5_prj.htm

Yeah that was something I was looking at.  I'm probably going to start with just a single triode gain stage though.  It won't really do anything useful but I want to play around with something simple until I get the hang of all the parameters.
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dBel84

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Re: Designing and building my own tube amp...
« Reply #15 on: September 25, 2012, 01:59:00 AM »
still can't find that dern pdf but this looks handy http://www.guitarstudio.tv/documents/Designing-V-T-Amplifiers.pdf

Doug gives a little tutorial on calculating triode current on his MEHA project pages too ( ecp audio - posted above )

..dB
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fishski13

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Re: Designing and building my own tube amp...
« Reply #16 on: September 26, 2012, 03:23:28 AM »
Mav,

i don't know the schematic for the Crack, but it strikes me as a great learning tool to explore amplifier design and why the designers made the selections and choices they did.  reverse engineer it.  you're going to need to be adept at reading tube data sheets and drawing load lines.  Broskie has software as well. 

i really think you would like Morgan Jones - he offers very sensible, logical reasoning. 

here's another link i forgot to mention: http://jacquesricher.com/NEETS/

 headbang
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maverickronin

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Re: Designing and building my own tube amp...
« Reply #17 on: September 26, 2012, 03:46:17 AM »
Quote from: fishski13 on September 26, 2012, 03:23:28 AM
Mav,

i don't know the schematic for the Crack, but it strikes me as a great learning tool to explore amplifier design and why the designers made the selections and choices they did.  reverse engineer it.  you're going to need to be adept at reading tube data sheets and drawing load lines.  Broskie has software as well. 

i really think you would like Morgan Jones - he offers very sensible, logical reasoning. 

here's another link i forgot to mention: http://jacquesricher.com/NEETS/

 headbang

I haven't checked for sure yet but after doing some reading I think I've mostly figured out the Crack.  It's a little cramped, and the sockets aren't the best quality so I don't want to mess around with it much until I at least get some better sockets and maybe some more spare parts.  I'll probably end up building my own copy from scratch to make sure I understand it.

Right now I'm mostly making a list of parts I'd need and another list of reference material.

Thanks for that link.  Looks interesting.
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maverickronin

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Re: Designing and building my own tube amp...
« Reply #18 on: September 29, 2012, 03:36:25 AM »
So rather hilariously I've noticed that my Bottlehead Crack actually makes my PFE232 more neutral.  Compare the FR and impedance plots and add ~120-ish Zout.  I noticed that a while ago but never got around to trying it.

OTOH it kinda defeats the whole point of them.  I like that they sound natural at really low volumes so I can listen all day long w/o ruining my hearing.  Also, the Crack really gets cranky like where they dip down to 15 ohms at ~9k and it makes maracas and cymbals sound like static.  The rest of the spectrum isn't that bad, though I'd rather lay off the syrup and stick with my O2 or UHA-4.

They just don't look as impressive on my desk though...
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