Elkin 4 tube any help is definatly appreciated.

[snippits75]

Nomad you are the man! There are only a few people that I know about that will work on Elkin amps here in NC. Thankfully, Ray is still sitting at the bench.

My four tube Elkin still uses two voltage regulator tubes. I was going to ask Ray about upgrading to solid state regulation, but it came back to me don't fix something that's not broken.

 

[EchoKilo]

Well after 3 years since I wrote this post I finally buttoned it up. Removed the capacitors bridged across the original ones. Added 4 new electrolytic with new bleeders. New OA2 tubes and new zener diodes for the bias chain. If it fails again, I will be be upgrading to the TIP 50 configuration. I appreciate the time of everyone's responses. 73s

 

[Hawkeye351]

I know this is an old thread, but I have a question pertaining to this same amp.

4-tube elkin, no hi/lo switch, same internally as above pics.

In the pic posted a few posts back is a close up of the transistor you all were referencing. Well, under that transistor tab is a disc capacitor with what looks like 002/ kv. This cap comes off a ground tab of the tap rail and goes over to an AC input wire.

This one in this amp is blowed up, top gone, black and open. The owner had the bottom cover off and didn't notice one of the fuse holder wires got pinched between the bottom cover and chassis when he put cover back on. When he plugged it up, it immediately blew the fuse and he unhooked it and then called me. I know nothing about amps, I was gonna have my amp guy look at it but he's been bad off lately. So, I checked it out and found (and fixed) the pinched wire, replaced the fuse and hooked it up. It comes on, but then I noticed what looked like a cigarette tip turning red in that area and spotted that cap blown up and cooking inside it.

My question is, what's the value of that cap?

Sorry for bringing up an old post.

 

[snippits75]

tramdr from CB Radio History Channel on YouTube reversed engineered, power supply schematic only, an Elkin four tube that is ob2(tubes) regulated. Schematics are on the video. Not sure if it will help you or not. He has some other videos on Elkin amps too.

Send tramdr some pictures, or make a video too. Some of the amp guys on this forum might be able to help too. Hope you get it fixed. Four tube Elkin is a good amp.

 

[Hawkeye351]

I've seen that video before, but that schematic doesn't show the value of the cap in question.

Here is the pic kopcicle posted which shows some of the value of the cap in question. I can see what looks like ?02 and ?kv. I'm assuming it's a .002uf at 1kv, is this correct?

 

[nomadradio]

The red circle hides it, but it looks as if one side of this disc cap is grounded?

If so, it's just a decoupling (bypass) capacitor. Good chance any value between .01 and .001 will probably do the job. Not knowing where the yellow wire goes that connects the to the cap's other side, a 2kv rating would be safe. And if the yellow wire leads to a low voltage a 1kV might be overkill. But overkill almost never causes trouble when it comes to the cap's voltage rating.

73

 

[Hawkeye351]

The yellow wire solders onto the same rail tap as one of the 110v input lines. The other end of that yellow wire goes to the fuse holder. The cap goes from that same tap (110v and yellow wire tap), over to another tap that is tied to ground through a mounting screw for the rail.

Thank you nomad, your help is always greatly appreciated.

 

[EchoKilo]

I've seen that video before, but that schematic doesn't show the value of the cap in question.

Here is the pic kopcicle posted which shows some of the value of the cap in question. I can see what looks like ?02 and ?kv. I'm assuming it's a .002uf at 1kv, is this correct?
View attachment 67869

My apologies on the late reply you are correct it is a .002 1KV ceramic cap. It's a decoupling cap for the ac line the yellow wire goes to the fuse holder and the other end to ground.

 

[Hawkeye351]

I replaced it, checked everything else out, hooked it up and let it warm up for bout 20 minutes, adjusted match between radio and amp to a 1:1, tuned it out and got around 525w pep swing, bout 380w peak swing and around 250w average(?) swing with a 100w key. Does that sound right for a 4 tube elkin? Also, anything above a 1w deadkey will jack the output deadkey up tremendously.
Example:
1w deadkey in equals 100w deadkey out,
1.5w deadkey in equals 175w deadkey out,
2w deadkey in equals 210w deadkey out,
etc,,,,

Amp runs great at a 1w deadkey input, no heating issues, no cherrying up, no hums, etc... Got great reports on it on the air.

Owner now has it and is very pleased with it. He knows not to put any higher than a 1w key into it. He actually stuck a sticky note on it beside the input so239 stating no higher than 1w deadkey input, lol...smart idea though...lol...

Thank you guys again.

 

[EchoKilo]

I replaced it, checked everything else out, hooked it up and let it warm up for bout 20 minutes, adjusted match between radio and amp to a 1:1, tuned it out and got around 525w pep swing, bout 380w peak swing and around 250w average(?) swing with a 100w key. Does that sound right for a 4 tube elkin? Also, anything above a 1w deadkey will jack the output deadkey up tremendously.
Example:
1w deadkey in equals 100w deadkey out,
1.5w deadkey in equals 175w deadkey out,
2w deadkey in equals 210w deadkey out,
etc,,,,

Amp runs great at a 1w deadkey input, no heating issues, no cherrying up, no hums, etc... Got great reports on it on the air.

Owner now has it and is very pleased with it. He knows not to put any higher than a 1w key into it. He actually stuck a sticky note on it beside the input so239 stating no higher than 1w deadkey input, lol...smart idea though...lol...

Thank you guys again.

How did you get your input swr down? I have played with this thing for a while. I can't get it below 2:1. 500 PEP damn that's pretty sweet. I'm getting about with 1.5 wdk in I'm getting 20 swinging to 350. 73s man

 

[snippits75]

How did you get your input swr down? I have played with this thing for a while. I can't get it below 2:1. 500 PEP damn that's pretty sweet. I'm getting about with 1.5 wdk in I'm getting 20 swinging to 350. 73s man

There is a variable tuner inside the case(bottom) that tunes the input. Flip it upside down, and take the bottom off. It's been a few years since I have tuned the input on a Elkin four tube and six tube. Take a picture of it if you can.

 

[EchoKilo]

There is a variable tuner inside the case(bottom) that tunes the input. Flip it upside down, and take the bottom off. It's been a few years since I have tuned the input on a Elkin four tube and six tube. Take a picture of it if you can.

Oh yea I know just what your talking about. I found a sweet spot the lowest I could obtain was 1.7:1 which I mean isn't to awful my output swr is 1.3:1. 73s I appreciate your reply.

 

[snippits75]

You tuned it with amp on yes? There are other tuners in there. My six tube had six or seven of the tuners that is shown in the picture.

The man that built and designed the Elkin amps told me himself to use six foot jumpers. I was at Ray's shop in Elkin, NC to pick up my four tube 12DQ6B amp that he had done a tune up on when he told me to use six foot jumpers.

He also said three to five watts dead key from radio. Also, he said that every 12DQ6B tube was good for 25 watts carrier with the amp on. Four tube carrier at 100 watts and six tube at 150 watts.

 

[EchoKilo]

You tuned it with amp on yes? There are other tuners in there. My six tube had six or seven of the tuners that is shown in the picture.

The man that built and designed the Elkin amps told me himself to use six foot jumpers. I was at Ray's shop in Elkin, NC to pick up my four tube 12DQ6B amp that he had done a tune up on when he told me to use six foot jumpers.

He also said three to five watts dead key from radio. Also, he said that every 12DQ6B tube was good for 25 watts carrier with the amp on. Four tube carrier at 100 watts and six tube at 150 watts.

Yes sir, with the amp off my pass though is 1.2:1 with it on 1.7 is the lowest I can get it to go. I am going to have to remember that I never knew that they could he driven that hard. Thank you for the info I will have to look around for more variables.

 

[snippits75]

If you got the input to adjust with the tuner in the picture, then don't touch the other ones especially if you don't know what they are for. I know at least one of them is for bias tune, and I have no idea what all the others do.