Tweet
Well this is just about what you said close enough for me to think you are right I could give you a list of everything connected to each tube socket if you think it would be wise.oh well here goes from top socket to bottom in the first picture I sent. pin# 1 and 2 don,t have anything on them. pin# 3 has a jump wire over to the middle socket pin# 4 , pin# 4 top socket is con, to the resistor that is hooked to the strip at that end a wire from the power cord is con to the strip,pin# 6 is not hooked to anything,pin# 7 , has a red wire coming from the multi-section cap (orange cardboard tube looking thing)it also has a yellow wire connected to pin #7 that goes to the on/off/tone pot. it also has a little resistor that jumps over to the num#6 pin on the middle tube socket. the. tone pot on/off has a wire from the power cord/wall plug it also has a black wire coming from the multi-section cap. ok here is what is hooked to the middle tube socket. pin #1 is connected to a yellow wire coming from the multi -section cap, and a little black resistor with a silver stripe black stripe and a blue stripe.that is con. to the strip pin#2 has a little resistor also con. to the strip it also has a cap .0047MF 200VDC that jumps over to the bottom tube socket pin #7 pin#3 middle socket has a jump wire to bottom socket pin#4 pin#4 middle socket jump wire back to top socket pin#3 pin#5 nothing pin#6 green wire to multi -section cap 2 resistors one jumps to top socket#7 pin one resistor jumps to the #7 pin on the bottom socket #7 pin middle socket has a green wire that runs back to the strip ok bottom tube socket pin#1 has a .015 mfd tone cap and a resistor both are going back to the strip #2 pin has a black wire going to the volume pot and a resistor to the strip,pin # 3 has a resistor to the strip and a jump wire to the strip back where the resistor from the middle socket pin#2 connects pin #4 jump wire back to middle socket pin#3 pin#5and#6 are bare fineally pin#7 of course has the tone cap.047 mfd 200vdc bact to pin#1 middle socket well that is it so let me know what you think and thanks a million for all the help
-
-
The 12av or u will be on the jack side, the 50C5 next and the 35W4 last.Comment
-
thank you I will give it a try. This amp has a 2 wire power cord can it be replaced with a three wire plug or power cord, Also if I replace it with the 3 wire cord do I solder the ground to the metal chasis ?Comment
-
Ok thanks a million ! is there anything I can add to this amp to make it ether sound better or make it safer? and I will ask you the same question as I asked clyde 1 can I change the power cord to a 3 wire cord and if so do I solder the ground to the metal chasis ? Thanks again this will help allot!Comment
-
Ok I think you are right as to the tube placement, because when I plug in and turn on after it warms up it has a loud buzz! before with the tubes the other way it made no sound. Now what do you think is making the loud buzz?Comment
-
Ok I tried it the way this schematic is and it does not make a sound using the tube placement that clyde 1 suggested it makes the loud buzz after it warms up. just to note the buzz does NOT change with turning the volume knob up or down. I think this is the right tube placement and that there is something else wrong with this little amp do you have any ideas as to what might cause it?Comment
-
The 12V6 tube does not have a brand name or anything else on it just the 12AV6 wow this is allot more complicated than it first looks , But I want to learn it so I will do some more research, Primary leads? if you mean the two wires on the power source or wall plug? one goes to the on/off switch or pot the other wire goes to the strip and there is a rectangler resister that goes to pin# 4 of the socket at top of the pic I sent. it is actually as you look at the amp from the back standing upright it is the socket on the right. that pic I sent was turned .From the lug on the on/off tone pot where the wire goes it has a wire going to the strip then to the bottom socket or the one on the far left if it is sitting upright.pin #3 so I am guessing that the socket on the far left or the bottom in the pic I sent first gets power first when you turn on the power switch. I think the power goes from left to right so the power goes from switch to pin#3then socket on the left pin#4has a jump wire to the middle socket pin#3 pin#4 middle socket has a jump wire to the socket on the right pin#3 I don,t mean to confuse you as to the sockets the pic I sent has the socket on the right side as you look at the amp from the back sitting up right (on the top) thanks again for the helpComment
-
Safest would be isolation x former. Do a search on the forum for 'isolation transformer'. The forum has covered this many times. Do this and at same time re wire for three wire plug and add a fuse, etc. Also note that these transformer less circuits make a meaningful distinction between 'common' and 'chassis'. Common can be hot if you flip the plug. Chassi can be hot if you get something wrong.Originally posted by RitzRed View Post
Your hum is likely in part caused by that very vintage original multi section filter cap (the big one). Try AES for a look alike replacement. Tubesandmore dot com
In the threads about isolation transformers there will be a common triad transformer part that people will mention. It is around 12 bucks or so.Comment
-
The RCA shemo says nothing about where to place the tubes only what the circuit looks like. Anyhow, making a loud buzz is probably good news. It suggests that the 50c5 and 35 w4 are likely working. Did you try putting some music through it? Any kind of signal will work. I would not do guitar since you don't know how safe it all is yet.Originally posted by RitzRed View PostComment
-
Ok thanks I will do these things you say and see if that is it man I hope so thanks again for all the info.Comment
-
one more question, the little transformer that is in this amp does not look good can this be replaced with a better or bigger model ? I am not trying to keep this amp original I am trying to make a good sounding harp or guitar amp from it.thanks again for your helpComment
-
Yes it can be easily replaced. Chances are that it is perfectly fine as is. To replace it you want to consider the impedance the 50c5 is looking for and the load (speaker) you want to drive, and the power, which is negligible here. Check the data sheet to see what the tube is looking for. Check the speaker to see what ohms it is (4?) or measure it with meter.Originally posted by RitzRed View Post
Honestly, before lunging for the transformer, I would play with speakers first in the search for better sound. After fixing the hum, of course.
If you are curious about transformers look at the web site for musical power supplies. The guy there gives good service and he is clear about the specs plus he makes small single ended OTs that have 4-8-16 ohm taps, so you could play with different speakers.Comment
-
Just a thought.
Vintage transformers did look old when they where new.
Unless the thing is actually crumbling & it tests good, why replace it.Comment
-
ok thanks againComment
-
right,how do you test it? I was thinking of replacing it with a better newer oneComment
Comment