Looking for Help: Designing a Tube Amp/DAC
Mar 31, 2013 at 7:09 PM Thread Starter Post #1 of 3

yunaforever009

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Heya folks,
 
First off: I have absolutely been enthralled by the works imagined, fashioned, and crafted within this forum. I started reading through posts here solely on a whim of curiosity, developed a strong sense of "Oh, that looks gorgeous", was afflicted by the feeling of "I think I could make that", and then pained by the realization that holy batman, there is a lot of stuff here. So, kudos! 
 
Secondly: If anyone has any recommended places to dig deep, I would be grateful for such recommendation. I am looking for a multi-use amp/DAC that will take USB / 1/8 input, output aux / RCA pre-amp, or output aux post-amp. The reason being, I have a Marantz AVR that I have connected to my HT set up but my fronts I'd love to be able to run source from my computer - DIY Tube DAC - Marantz Amp - Speakers (Pair of Klipsch RF-7 iis). I also have a Sennheiser HD595 and JHAudio JH13s that I'd like to be able to run Computer - DIY Tube DAC - Tube Amp portion - Headphones. 
 
As I am not at the point to run balanced headphones, a balanced board is not necessary. My fiancee has quite a bit of experience with electronics and soldering so with my nascent skills and his experience, I'm confident in being able to manufacture enclosure, design, test and execute a point to point or board based system. The amp can be solid state based such as the Aune T1 if necessary. 
 
My overriding goals with a venture like this is to develop a system that can achieve or at least grapple with the following themes in order of importance to myself:
A. Deliver a crisp but not necessarily tonally neutral sound signature. My JH13s are very sensitive to any noise from the system so precision is key but this project is to supplement my current listening habits which already includes a fairly tone neutral DAC/Amp.
B. Have tubes in it. Look cool. I know this sounds both vague and rather amateurish, but my first "Wait, what did they build?" moment was because I saw a tube amp being run at night. I am intrigued, nay, enchanted, by the looks and suave character inherent in a tube system. This is why I only reference the Aune T1 as it utilizes a single tube. I would undertake the additional complications inherent in additional tubes precisely due to looks. (And, tell no-one, but running diodes underneath as needed to create the lighting effects common to some tubes.... is something I would do)
C. Utilize USB input / 1/8 input, 1/8 output. Additional outputs/inputs are fine and their added versatility would not be a detriment but I'd dislike having a self-made product only to undermine it by having to use a rca to 1/8 adapted dangling out the front. 
D. Have the ability to use just the DAC portion or a DAC/Amp comprehensive solution. 
E. Be under ~300. This is really just a generic limit because a lot of the cost inherent in enclosure I can offset as my fiancee has quite a workshop I can call upon and our best friends are antique and electronics purveyors, allowing decent access to well-priced tubes. 
 
I've looked at items such as the Millet Minimax, the Opus by Twisted Pear, the Bottlehead series of amps, Bijou amp... but can't seem to find a good source for starting to delve into a tube DAC DIY project, let alone one implementing an Amp within it as well. Oh, and a, you need to read more things, comment, is totally okay. All fun things must come with education. 
 
Okay, before I can ramble any more and take more time from the busy hands of you all,
 
With warmest regards, I remain, sincerely yours,
William Koster
 
Apr 1, 2013 at 12:10 PM Post #2 of 3
Looks like you have a solid idea of what you want to build, i have a similar project that's on going. After many hours of planning and testing on proto boards i decided on some things.
 
#1 The dac portion is best left as a stand alone unit so it can be used as a source for any amplifier.
#2 I used jan6418 valves which are highly microphonic, while not a deal breaker in the tube vs solid state battle it kinda sucks to hear a ringing every time you bump into the desk so just something to keep in mind when picking a tube.
 
Apr 2, 2013 at 9:16 PM Post #3 of 3
And yeah, that is definitely something I'm fully okay with. As for the Jan6418 tip, my thanks, I would have probably not noticed that until it was a problem which would be fairly late in the game!
 
So, I guess now just to try to find a discrete tube DAC since you had mentioned it was best left discrete.
 
My thanks,
William
 

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