[beachgeek]

Well you got the ball rolling & everyone talking.  Sounds like you either need to learn how to solder or don't want to get your hands dirty.  Whatever, can't be a good engineer without real hands-on down in the mud, burning stuff up once in a while.

 

[dBs]

I have no problem soldering. The issue is, until I know the value of parts that I need, by doing the computer/book/paper/theory work, I can't exactly BUY anything to BUILD anything. Unless I buy all pots and variable capacitors for every component and just start turning knobs, I'm not going to be able to magically know what value part to get for element. In college, I had access to a storehouse of parts and testing equipment. Now that I'm out of college, I don't have that luxury. All I have now, is an iron, and a DMM. I don't cache of parts that I can just grab and throw together to test my ideas.
 
What people are wanting me to do is build someone else's proven design (which is basically has been reduced to anyway). What I have, exhaustively, stated, is that I'm ready for that next step. I can build a Lego set, been there done that. At what point does a person become magically deemed to be "ready" to make it to the harrowed halls of designing from scratch?
 
I would love to be able to start throwing things together now and trying stuff out. I would have long ago if I actually had a mass of parts cached up like most of the people here do. I wouldn't have had the patience NOT to, but since I don't have parts laying around at my disposal of all different sizes and values, I have to be patient and buy stuff that I think will work.
 
I went ambitious with this project, more than some would have liked me to go. That's fine, I have no problem with that. It is what it is and I am VERY close to being ready to actually making the jump of prep work into hands on. I do find it ironic that in the beginning, most of what I heard was that I should be building a plan to work from, now all I hear is to forget the plan and DO something. All in due time.
 
If it makes everyone feel better to think that I'm just some hard-headed youth that isn't willing to listen to the wisdom of his elders, then that's fine. At this point, I just wish the topic would actually move to something with more substance to it. The sooner I figure out those last unknown values, the sooner I get to fulfilling everyone's shared dream for me, hehehe.

 

[regal]

What you are missing is its all been done before,  sure you might come across some combo of tubes in a topology that hasn't been done before but so what.
 
The only thing left for DIY headphone tube research is DHT's and Hybrids.   Make one of those work and then you can "say" you designed from scratch if that is your goal.

 

[dBs]

You're absolutely right about that. But there is something to be said about doing it from the ground up. I like that =D

 

[FrankCooter]

 
Quote:

 Basically any tube amp schematic for a mu-follower looks almost exactly how mine looks.

No, they don't look like yours, but it won't do you any good if we fix it. For a start though, what's your output transformer doing hanging off the cathode follower of the upper pentode rather than coming off the plate of the lower triode.?  What function is the choke above the pentode serving? Is a single 6J5 suitable for transformer loading? You're mixing up OTL and para-feed topologies. Pick one and stick with it.
 
I see you live in Ridgecrest. Some Saturday, drive down to LA (San Fernando) and visit an electronics suplus/junk store called Apex. It's huge and dirt cheap. Buy yourself a variety of passive components, connectors, wire, breadboard materials etc. Pick up a few junk tubes and transformers off Ebay. Experiment. Play around with your ideas. When you get something roughly working, then refine it by modeling. Keep it simple at first.
 
Regal's suggestion of doing something with a small DHT is a good one. It's one of the few incompletely explored areas left in tube headphone design. It's a big interest of mine as well. How about a mu follower with a DHT on the bottom? A 26 or a 112A is pretty much a DHT  6J5. You get everything else together and I'll contribute a couple of 26's.
 
 
 

 

 

[Uncle Erik]

Quote:

I see you live in Ridgecrest. Some Saturday, drive down to LA (San Fernando) and visit an electronics suplus/junk store called Apex. It's huge and dirt cheap. Buy yourself a variety of passive components, connectors, wire, breadboard materials etc. Pick up a few junk tubes and transformers off Ebay. Experiment. Play around with your ideas. When you get something roughly working, then refine it by modeling. Keep it simple at first.

dBs, just wanted to encourage you to visit Apex.  Be sure to give yourself at least 5-6 hours.  There are lots and lots of boxes that need looking through.

 

[beachgeek]

Shopping through old electronics stuff is better than shopping for clothes, although not by much.

 
P.S. Shopping is a sport!

 

[dBs]

Quote:

Shopping through old electronics stuff is better than shopping for clothes, although not by much.

 
P.S. Shopping is a sport!

Indeed it is a sport!

 
I have been looking for an excuse to go to LA and test out Verizon vs AT&T (running both right now for a personal test, lol). I will maybe see about whipping up some super quick and easy schematics so that I have SOME kind of direction when I'm down there, otherwise I may come back with a ton of stuff...none of it useful =P
 
I will still continue with this current design so far as well. I still fail to see any problems that I wasn't already aware MAY be a problem (the parafeed in conjunction with pentode current source-the choke above the plate). The output from the cathode of the current source IS the recommended output location. I can link you to any number of places that confirm that as well as quote Jones' Valve Amplifiers book, so I know I am right there. Otherwise, it's just a pieced together standard pentode current source above a standard mu-follower topology. There might be a part or two that could be omitted where the two different topologies merge, but I can't find anything that wouldn't detract from the intended performance. The screen resistor and capacitor are required for the pentode current source operation for the 100% feedback. The network of resistors and single capacitor between the pentode and triode are staples in any mu-follower topology. The capacitor before the output transformer is part of the parafeed. I've admitted from the beginning that the pentode current source in series with the choke portion of the parafeed may be problematic. Usually the choke acts as a semi-current source when in a parafeed configuration, and two current sources in series is a no-no. I figured this was something I had never seen before and thus I am willing to take the gamble to find out. If a 6sn7 can push an output transformer, a 6j5 should be able to.
 
At the very least, even if this particular design is destined for failure (I don't expect a symphony without some tweaking, but I am confident in the design), it gives me a direction for parts to buy. Unless there is a 1ohm-10Mohm assortment pack I can buy, I have to have some kind of a direction, and I would like if it was the one I have been working off and on with for this long.
 

 

[J-Pak]

dBs just curious did this project come to fruition?