rebuilding tone control block - Printable Version
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rebuilding tone control block - bfrohwein - 02-18-2013
Hello! I'm trying to work on my tone control. the problem is I'm not sure how to connect the new caps. I removed the tarry-goo and both caps came out. one still soldered to the bucket.
the loose wire was easy to find and trace back to the output tube.
[Image: http://i1303.photobucket.com/albums/ag147/bfrohwein/610-Tone-control_schm_zpsbd4132e0.jpg]
The cap in the foreground below, has a bit of the wire on it from the 42 tube and the bit of black wire on it that appears that it was attached to the isolated part of the switch
[Image: http://i1303.photobucket.com/albums/ag147/bfrohwein/tonecontrolsansgoo_zps37f90462.jpg]
I'm just having confidence issues around how to hook them up.
would I hook them up like this? where the unconnected lead would go to the wire connected to the plate of the 42 tube.
[Image: http://i1303.photobucket.com/albums/ag147/bfrohwein/tonecontrolmockup_zpsf3903a6e.jpg]
thanks a bunch..
Bret
RE: rebuilding tone control block - Radioroslyn - 02-18-2013
Yup the .01 lead goes to the chassis and the .02 goes to the lead to the plate of the 42.
Terry
RE: rebuilding tone control block - bfrohwein - 02-18-2013
Terry, it did seem a bit like a simple question, after sleeping on it, but thank you..
RE: rebuilding tone control block - Radioroslyn - 02-18-2013
No problem my friend sometimes even the simpler things confound me too.Just as for the fun of it you can play with the values of those two caps. Must be 600v jobs or better. You could change the .02 to a .005 this will make the audio very bright(will increase the high frequency response). Those caps act as a treble control and to stabilize the plate of the 42, it keeps it from oscillating. The 610 is a nice easy set to work on and is a great little player.
Terry
RE: rebuilding tone control block - bfrohwein - 02-18-2013
Thanks Terry.. I was actually going to try that. I guess being from a modern era.. I've never really been very satisfied with the 2 to 4 tone choices on the old radios. seems to me the choices are bright, muddy, muddier & talking with your hand over your mouth. I'll have to get me one of those Zenith's with the RadioOrgan tone controls one of these days.
The caps I put in there were 400 volts.. but I have some 1600's on order. I read on the antique radio forum, somewhere, that when you have caps connected directly to the plate of the output tube to use 1600 volt or better, because of possible spikes from the plate of the output tube. I figure the 400's are ok for testing. The 3 conductor cloth speaker wire I ordered from Radio Daze is on back order... Boo.. so the new caps will probably show up before the wire does. I Should've gone with my original plan to just braid the brown cloth speaker wire like the original. I just didn't have enough to do it. Although, I may end up doing that anyhow, as the hole the wires go through is very narrow. my luck will be that the cloth sleeve won't fit.
RE: rebuilding tone control block - Radioroslyn - 02-18-2013
You could just replace the switch with a 500K pot. Then you would have a continuous control.
Terry
RE: rebuilding tone control block - Arran - 02-19-2013
The only place where I have heard (or read) it recommended to use higher a higher voltage cap is across the primary of the output transformer, I have not heard of it being an issue between plate and ground. In this case, if the diagram is accurate, closing the switch increases the capacity, opening it decreases it since you have two caps in series, it's more a treble cutting control then a tone control. Also since they are in series that means that the total voltage will be double that of a single cap so the only cap that you should be concerned with in terms of voltage rating is the .02 uf one. Tube radio audio isn't generally that bad as long as you replace all of the bias resistors in the audio stages as well as the caps.
Regards
Arran
RE: rebuilding tone control block - bfrohwein - 02-19-2013
Ooops... Arran, You're right.. I checked my notes.. that particular control was a .01 that connected to the negative side of the e-caps and then the transformer center tap.. :-) well.. I have plenty of .01's @ 630.. for the .02, I'll use one of the orange drops when they come in.
after you explained what this particular control actually does.. my description makes more sense to me.. that's exactly what it sounds like.
That's an Idea, Terry.. I might just try that.
Thanks again, guys.. You've been a tremendous help and wealth of knowledge.
I'm sure I'll have a million more questions.. especially if I keep cleaning up @ these auctions.