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Posts by Zaubertuba

How to not screw up your nice oak faceplate (click on the pics for the larger versions):     I happened to have a template bushing for my Dremel tool plunge router attachment.  I'll be using a fresh multi-purpose spiral bit on the highest speed setting.   The offset for the guide is exactly 1/4"...I traced the outline, added a quarter inch, and also took the opportunity to adjust the curves a bit. I cut the outline with a jigsaw and spent some time cleaning up the...
I did a scratch template for the front panel.  The first template I went a little crazy with the French curves and it ended up a little too organic.   This one's a little better:         Oh...and the coupling caps don't need to be that big.     .1uF should be fine.  I'll fix that the next revision I post.
Working to tame the gain a bit....   Assuming my math is right, differential gain without feedback is around 30.  This version with the feedback resistance set at 240K reduces that to 22.  If I increase the input impedance a hair I can shave another 2 off each triode for a gain of 18.
 LOL and here I went and simplified the CCS before you posted that!   It's all good though...I actually learned a bit in redoing it, so maybe when I put the Cascode version back in I can calculate the values better.  Is it useful to have more voltage swing across the CCS?  If it doesn't really matter I'll rework it tomorrow swinging just ground--->-15V. Also added some NFB.  A little scared how the numbers will work out because the input impedance is so low (picked the...
You're right--I was trying to fully utilize my stereo pots but the legitimate shunt would probably work better anyway.  Fixed.   I also redid the CCS.     I was just thinking, perhaps I could add some local NFB to tame the gain a bit?
 Thanks-I'm looking forward to looking through that pass article. I really appreciate you wanting to keep me from going down the wrong dark path (I do that with my son sometimes   ).  Here's my dilemma with changing the topology this late in the game: -I've already invested in a balanced setup and the bulk of the components for this balanced build (including some of the casework which would involve scrapping some expensive copper I won't be able to use in an SE...
  LOL I was just going through all sorts of the mental gyrations you'd expect when you have two experts giving you conflicting information, when I realized I have to use a different CCS to do what dsavitsk is suggesting, anyway.   By the way thanks for posting Kevin, and I love the title on your calling card--my Dad used to use that phrase from time to time, and I've found myself using it as well.
I drew up the schematic in a format that should be a little easier to read.      Another question...Q1 is actually a darlington pair.  I thought I had a grasp of calculating the current for the CCS but well, now I'm not so sure...   ...can anyone recommend a good reference on the topic?       EDIT: Forgot the tube label!  
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...
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