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Posts by Zaubertuba

Cat5e is actually pretty good quality stuff--check out what Chris VenHaus has done with it: http://www.venhaus1.com/diycatfivecables.html   I use it all the time for projects for my low-voltage stuff.  It's cheap to find and easy to work with.  Maybe some litz-braided interconnects would be fun.   Do spend some time and pour over these threads, the first might already have answers to some of your...
You're not likely to get a factor of 10 in perceived improvement from doing your own mods.  Most of the mods I've done (and seen) have been noticable, but incremental in nature.  That said, if you dig a little you can find things that work (and avoid those that don't).  Way back when the HD555/595's came out, it was as easy as removing a foam pad to turn the former into the latter, since we found out they use the same drivers.  That was an easy and tangible mod that could...
Boy that's a lot more elegant solution. So from what I read, it sounds like putting the series resistors at 90% of the value of the shunt pots preserves the pot curve the most and provides the least attenuation at full volume.  Closest value is 4.7k, so, a balanced shunt using my faders before the ltp might look something like...   Am I on the right track?  Seems like getting the pot out from between the ltp and the JISBOS as you suggest would cover a multude of sins...
...and I'm sure the electronics bench tube-lesson will continue. Meanwhile, in the garage, I've made some advancements in the case-work...     Lubrication and a bi-metal hole saw works surprisingly well when you can't afford a $45 step-bit:         Drilled and marked-up sheet ready for bending in my home-made metal brake:       I had to cut a pocket in the brake to fit the compound bend:       Completed tube bracket.  I'll polish the visible parts to...
I *really* appreciate the feedback. Learning a lot here.   
Thanks so much for giving my napkin a look, dsavitsk! -The CCS should be an easy fix--the only reason I was pulling the base voltage from the HT was my low-voltage supply floated in my mock-up. The low-voltage supply does have a negative rail. -I have some lower-mu tubes around but the 12ax7's were the only ones I at least had a similar pair of.  I do have some 12at7's or 12au7's I can work up, and order better-matched tubes later, I suppose.  I gravitated away from the...
This has been rattling around in my brain for months, but I've finally made enough consistent progress to see the light at the end of the tunnel.  I've had the Jisbos/Alpha 20 boards from AMB for awhile, but have only recently gotten comfortable enough with tube design to get a reasonable prototype running (well, at least one channel).   Basically, this will be a long-tailed-pair 12ax7 input/gain stage followed by an AMB JISBOS buffer.  I'll use a CCS to improve...
Sweet! I've been pouring over Merlin Blencowe's excellent book on instrument preamp design for the past year. I know it's not a resource specifically for Hifi but I've learned a heckuva lot about what makes a tube tick. Still have lots to learn, I'm sure! If I have to spend any more money it'll likely be for the power supply--I have a basic unregulated 200V CR filtered supply worked up for prototyping but I fear that's not going to leave me a lot of headroom for what...
Have any of you tube guys toyed around with a long-tailed pair as a headphone amp gain stage?  It seems like an elegant way to get a differential input/output amp.   I have a quartet of JISBOS buffers I'm thinking of using as the output stage, and a bunch of preamp tubes (12au/x/t7's) sitting in my parts drawer from other instrument projects/tube rolling.  Thought I might try to hack together a balanced hybrid.  
Well, my curiosity got the best of me and I succumbed to an impulse buy---Emotiva's has a sale going on their XDA-2 for $250 so I snapped one up.   Didn't even consider this one before since it was out of my price range.   Figure if the headphone amp really does turn out to be weak (and I'll end up making a Y-Adapter just to see...don't want to have to re-re-terminate my headphones later), I could still finish my a20 balanced headphone project, and in the meantime I...
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