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ok i have a question about the schematic. the output transformer has a green, yellow and black wire for the speakers. the yellow wire is grounded why would that be? and the black wire is used for the negative feedback. does this seem right?

Well i have 2 jensen a12 field coil speakers as well as 2 15" magnavox field coil speakers that i wont be using. I just dont have the time or space for another project unfortunately.

Finally getting back to this. I will give the cap between pin 1 and ground a shot. After reading a bunch of different threads i am wondering if i will need to upgrade my output transformers to get any really good bottom end.

I just gave this a listen on my main speakers. It sounds really bright and there is no bottom end. I tried it with and without the choke and there wasnt much change. It might just be the way it is supposed to sound? I have changed all the caps but not the resistors yet.

I put the choke in before my first filter cap last night and it dropped my plate voltage to 320...to low? I will try switching out the resistor and see what i get. What do you think about adding a second a second 6sn7 to get more gain? How would i figure out if my pt can handle it? Thanks

C1 is .25 microfarad r1 is 120k and r4 is 2.2k. One thing i noticed as i am trying to learn is that there are no grid stop resistors... Would it help to add thase?

Ok thank you. after I have this running correctly I am probably going to have to figure out how to add another gain stage to this thing.

the choke i have on hand is a hammon 158m 10 henry 100ma current rating 400 volts

Thanks you guys for the help on this I am learning alot. So i hooked it up to the field coil speakers and my voltage dropped to 427 at the plates of the 6l6s also getting 21.8 volts of drop across the 241 ohm bias resistor. I went back and tried the permanent magnet speaker again and after i...

Without... Only hooked up to a permanent magnet speaker

took a few measurements last night. I am getting 475 volts on the plates of the output tubes...pretty high luckily i am only letting this run for a minute or 2 at a time so i don't cook anything. I will try to figure out what my plate current is this weekend.

Brought this amp up on a dbt last night and it seems to be working correctly. There is a little bit of hum but not too bad. I did have to jumper my center tap to ground in order to get this to work because i was not using the field coil speakers. All 4 speakers in the original cabinet are...

yes 2 sockets. i wonder if speaker 1 gets less dc current than speaker 2 so they both grab it from different spots in the circuit

Really appreciate the replies on this....It looks like all i would have to do is ground my center tap from the rectifier circuit in place of the field coil speaker.

ok i am having trouble wrapping my brain around this and i really want to understand it. the b+ goes through the field coil but where does it go after that? in the schematic b+ goes to the output transformer before it hits the field coil.

Thank you for the replies.... here is another question. It seems like the b+ goes through the field coil on pin 7 and comes out pins 1 and 3 but go to ground? assuming the the center tap of the rectifier circuit is grounded somehow off of the speaker 1 socket? sorry if this is not making sense

I looked at some other schematics and the only other place i could find it was in a guitar amp. In that case the resistor is a pot used as a brightness control for the amp. Would it be safe to remove this?

Getting ready to do the rebuild on these. I will try them with the field coil speakers first and then my choke. I do have a question about the schematic. what is the purpose of the cap and resistor that ties the plates of the 2 6l6's together?

I guess where I am at is I would like to build a nice sounding amp If that means it would be better to start from scratch then that is what i would do Maybe I can use some of these parts for that? I know that I don't want to use the field coil speakers I'm open to suggestions thank you for...

ok another question about this choke. How do i figure out how much current it needs to handle? When i go to look at the current draw of a 6l6gc and a 6sn7 do i look at the peek current or idle current?

Thank you guys for the replies and the link to the schematic. Here is a shot from the bottom of the amp I will start getting a list together of some of the parts i will need to order. I have a pair of fairly high efficiency speakers i would like to use these on. Would it be smart for me to...

I am a totally new to all this so you will have to take it slow and pardon any dumb questions i might have. Would my fist step be to pull the amps and purchase/replace all the capacitors and resistors? As far as a choke goes is the purpose of it to only filter out ac? and the coil in the...

I recently picked up a wurlitzer model 40 tone cabinet. The cabinet was complete but in pretty rough shape. I have a couple questions. first off it has a pair of 6420 line amplifiers in it. What would it take to turn these into a pair of mono blocks and where would i even start with a...

Airbag Disconnected. This may be their best yet, but all of their music is excellent!!

while you are waiting for the new diaphragms to be delivered you could take the diaphragms out of your kg4 and put it into the chorus tweeter