Ghost Notes Solved

[cliffc8488]

Thanks. 75 Superlead. Its fully recapped and has 50uf/50uf caps. I suspect the 100K plate resistor has drifted up. I am reading 164K but this is in circuit so it can be hard to tell. Teh 82 k reads 80k in circuit. PI is very closely balanced as well as power tubes are matched. Can the 100k plate resistor cause this?

It should read close to 100K in circuit. I'm guessing that's your problem.

 

[panhead]

Thanks. 75 Superlead. Its fully recapped and has 50uf/50uf caps. I suspect the 100K plate resistor has drifted up. I am reading 164K but this is in circuit so it can be hard to tell. Teh 82 k reads 80k in circuit. PI is very closely balanced as well as power tubes are matched. Can the 100k plate resistor cause this?

If you have tubes that you know are good. Run a pair in the middle 2/3 see if it does it. If it does run a pair on the outside 1 and 4 and see if does it.

 

[glip22]

It should read close to 100K in circuit. I'm guessing that's your problem.

Thanks. We will see. I'm waiting for the Pihers to deliver from Spain

If you have tubes that you know are good. Run a pair in the middle 2/3 see if it does it. If it does run a pair on the outside 1 and 4 and see if does it.

I did try this earlier on and still have it. It's not bad but more than I care for TY

 

[panhead]

How much you want for it LOL

 

[glip22]

How much you want for it LOL

LOL. There's more to it. It's an Elan Metalhead. Elan has an added tube that hits the circuit after the stock stages right before the cathode follower. This allows the amp to go from clean to mean with barely any volume loss better than any other mod I have played. When the pull pot is in the amp is fully stock. Literally, all stock , every part. The only difference is now the leads are shielded. The amp still ghosts a little when the added two gain stages are fully out of circuit so it is not the mod. I know Elans work, I have an 85 he did and I put the same mod in an 89 and it rips. I tweaked the circuit of course to my ear. Teh cathode caps he uses 22uf are too big. I will not alter the originals though.

 

[harddriver]

If you are going to replace it with a Phier eventually why don't you install a modern CF that measure exactly correct 100K and you'll know for sure if that was your problem. If that fixes it then install the Phier when you get them.

 

[glip22]

If you are going to replace it with a Phier eventually why don't you install a modern CF that measure exactly correct 100K and you'll know for sure if that was your problem. If that fixes it then install the Phier when you get them.

Actually found a Piher today in my pile that measured right at 100K. When I got the amp, I found the plate voltage on the PI on the 100K side quite low, so I tested the resistor. I pulled it today and it tested 164k out of circuit (big drift up). I replaced it, and one of the bias splitters that was testing 238, and the issue is corrected. If you really listen closely on the neck pickup higher registers most of the old Marshalls have it at volume to some degree but this 75 SL was very bad in many areas and on the bridge pickup also. Now it's fixed Bingo.

 

[harddriver]

Excellent news!

Thanks for updating us. This will be invaluable information for troubleshooting purposes in the future for someone having a similar issue.

So you replaced one of the bias splitter resistors as well?

 

[311splawndude]

Glad you got it figured out.

I didn't understand much of what you guys were talking about but it was interesting

 

[Rocker68]

Extremely informative thread. My understanding of how , what , and why just grew. Solves a lot of puzzles.

 

[glip22]

Excellent news!

Thanks for updating us. This will be invaluable information for troubleshooting purposes in the future for someone having a similar issue.

So you replaced one of the bias splitter resistors as well?

Thanks. Just because I replaced the splitter to have both closer in resistance. Had the board up so why not.

 

[Frank52387]

LOL. There's more to it. It's an Elan Metalhead. Elan has an added tube that hits the circuit after the stock stages right before the cathode follower. This allows the amp to go from clean to mean with barely any volume loss better than any other mod I have played. When the pull pot is in the amp is fully stock. Literally, all stock , every part. The only difference is now the leads are shielded. The amp still ghosts a little when the added two gain stages are fully out of circuit so it is not the mod. I know Elans work, I have an 85 he did and I put the same mod in an 89 and it rips. I tweaked the circuit of course to my ear. Teh cathode caps he uses 22uf are too big. I will not alter the originals though.

I just bought a 75 superlead with this metalhead mod by Elan Memran. I was trying to understand what the extra 2 knobs do once the extra gain mod is engaged.