[simon wagstaff]

so I am reading the review of some Conrad Johnson tube amp "special edition".  Better parts and stuff.

I have my U70 and am very happy with it but the kit nature of the thing makes me think I can't ruin the appearance of it and I am just handy enough with a soldering iron to be dangerous. I have
1) replaced the power cord with a heavier gauge (the old one was just lamp cord and the insulation was cracking)
2) performed the "choke" mod, a nice upgrade!
3) put the diodes around the rectifier tube
4) installed upgraded gold binding posts and input jacks. You can get some nice ones directly from China on e-bay.

Now comes the stupid part. Are there any parts upgrades that can be performed as drop in replacements? I am thinking that the capacitors in this unit may be 10 years old or so. any upgraded parts like capacitors or resistors that would be stupidly expensive for Frank to use but maybe not so stupid if you are already stupid?

I am thinking perhaps if I get bored I will replace the tube sockets with upgraded ones, and replace the wire that is currently running into them with some stupid silver, silver plated or stupid expensive high grade copper wire that is running about 4 bucks a foot. Any suggestions here would be appreciated. Might be a good way to waste a rainy afternoon, like the one we have here today.

I am pretty sure it would be way stupid to re-wire the whole thing with silver wire, 24 gauge is probably too thin, 18 gauge seems to be running about 20 bucks a foot. Quality copper wire is about 4 bucks a foot in what I have seen.

If this question is just too stupid please don't hurt my feelings....

[Wayner]

You also need to read the other article in front of that review (in Stereophile) about the placebo effect. Frank has already chosen the best parts for your amp's upgrade. Capacitors and resistors (unless damaged) should be just fine.

You might get more results, crawling into a whiskey barrel and going over Niagara Falls......

Wayner 

[simon wagstaff]

I think that going over Niagara Falls in a whiskey barrel would likely damage my hearing, at the very least.

[rcag_ils]

Now comes the stupid part. Are there any parts upgrades that can be performed as drop in replacements? I am thinking that the capacitors in this unit may be 10 years old or so. any upgraded parts like capacitors or resistors that would be stupidly expensive for Frank to use but maybe not so stupid if you are already stupid?

I am thinking perhaps if I get bored I will replace the tube sockets with upgraded ones, and replace the wire that is currently running into them with some stupid silver, silver plated or stupid expensive high grade copper wire that is running about 4 bucks a foot. Any suggestions here would be appreciated. Might be a good way to waste a rainy afternoon, like the one we have here today.

I am pretty sure it would be way stupid to re-wire the whole thing with silver wire, 24 gauge is probably too thin, 18 gauge seems to be running about 20 bucks a foot. Quality copper wire is about 4 bucks a foot in what I have seen.

If this question is just too stupid please don't hurt my feelings....

Well, if you are already stupid, there's no sense to make yourself even more stupid, just kidding.

I can think of a few useful upgrade, not so much for the "magic" parts, but the better quality parts.

Gold plated tube sockets are useful for preventing corrosion, a good thing.

Silver plated military grade teflon insolation wire are good, they use them all over military aircrafts, the insolation can withstand higher temperature than the Belden, or Alpha wire that you have, less burn during soldering makes your wiring look better. I don't know the price anymore, but it shouldn't be too bad. But you may want to get multiple colors of wires to make it look good, the cost will add up.

All these parts cost add up, then consider the time that you have to spend to put them in, if you have the time, and don't mind the little extra cost, do it.

[avahifi]

I doubt if replacing component parts or wiring will make any useful difference in your amp.  There are no 10 year old capacitors in your unit, all were replaced with the Ultimate 70  upgrade. All the resistors are 1% tolerance metal film type or metal oxide 5% types for the higher wattage ones.  These are matched channel to channel.  The film capacitors are selected for durability, low inductance, and low microphonics.  The only old and really thin wires in your unit are the hundreds of feet of wire wound in the three big transformers and the choke.  These would be the logical choice of wires to replace first, assuming you know how to wind your own transformers.

Probably more productive would be to engage in the sport of "tube rolling".  It is similar to "cow tipping" as done at night in Iowa, but somewhat more expensive and productive.  The amp can take 6CA7, EL34, or KT77 output tubes.  Some of my clients tell me this makes the Ultimate 70 better than ever.

Enjoy,

Frank Van Alstine

[simon wagstaff]

thanks for the input. I don't think I will be winding my own transformers any time soon. I have used the KT77 tubes and have a set of EL34 right now. Maybe my next set of tubes will be some 6CA7.  When I get another rainy weekend I might just replace the tube sockets, that would be more fun than cow tipping I think.

The ones directly on the circuit board seem like newer, nicer ones. That would mean just 5 sockets to replace.

[avahifi]

You could replace the front panel tube sockets with simple single contact probe jacks.  The only connections to them are the 1.56V bias test points.

In replacing the power tube sockets, make sure you get ones that have full circular contacts.  Many new ones only have a slitted or notched internal contact pin that does not make as good a contact as the originals.

Actually I suggest just spraying the tube sockets with Deoxit.  Remember that you have two spares sitting on the front panel if you have a working tube socket beyond repair.

Frank