JM/Wonderland amp issues

[rootz]

Martin, thanks it's a 500v cap too and that was the highest I could find , but yes it's on it's limit. Now I've removed the chassis bolt and replaced the phono socket on one of the reverb cables the amp has been perfect again all afternoon, no problems at all.

Seems unlikely that a small signal issue would be the cause of the arcing you saw. Intermittent faults are the worst...

unless the arcing i saw was just regular blue tube light but caused by the loud crackle the reverb cable was causing when the dimed amp was vibrating it?

Intermittent problems are indeed the worst


M

My point exactly Marcus. Easy to test too. If you still see blue flashing, but get no intermittent sound, it probably isn’t arcing (I think). Especially if it is all tubes at the same time like you said. If in doubt: upload a short video.

Standup transformers are my favourites. More room inside. Less possible interaction with reverb tanks. Just some holes for mounting and wiring, so easier to diy. Only downside I can think of is height in combination with a reverb tank in a head shell. Might be tight...

[norburybrook]

Now I've removed the chassis bolt

Have you considered a nylon bolt and nylon nut? That might be a better solution then no bolt at all?

With respect, 10thtx

I think you just need to put a heat shrink tube on the screw

Ha even simpler....just done it.....perfect


the hive mind comes to the rescue

amp is sounding great .



M

[Bombacaototal]

Glad you sorted it Marcus. My rectifier board is from AN identical to my yours, and I think I have same spacing to the chassis long mounting screws. Actually I think my mounting holes are just a bit further in front the yours, I might just be fine
I will check if I am having a similar issue although my amp is very quiet (except for the reverb which now is not too bad). Was it the screw between the board and the pilot?

[norburybrook]

Glad you sorted it Marcus. My rectifier board is from AN identical to my yours, and I think I have same spacing to the chassis long mounting screws. Actually I think my mounting holes are just a bit further in front the yours, I might just be fine
I will check if I am having a similar issue although my amp is very quiet (except for the reverb which now is not too bad). Was it the screw between the board and the pilot?

Raphael,

No it was the screw at the back there which almost runs between the backing board and the board on mine.

as I said I've head shrinked it and it's now OK. bear in mind my recifier wiring is slightly different to yous even though the boards are the same as I used a FWBR for the HT and a voltage doubler for the bias so that maybe why I had issues, strange they didn't show up at first though. Possibly the bolt has enough wiggle room to get close enough to pickup a current if it's positioned slightly differently in the chassis.

were the mounting holes already drilled? I can't remember.


M

[Bombacaototal]

Hi Marcus, thanks for clarifying. Yes in my case they were pre drilled but you have some good points on the difference in the rectifier and also placement of the mounting screws

I am glad you managed to sort it out

[fred.violleau]

Hey Marcus,

I. Glad you sorted the current issue. So no more voltage on the handle them

I wanted to circle back to the filters. I built a pedal version of Martin's filters. Found the step filters switch on mouser as well.
The interesting thing about putting the filters in a small Hammond box is you can test them with different ODS. BUT you need a d-lator to drive the filters. These are very lossy so when I tried these with the amps, send and return were quite high.

I have only 50watts amps and must say that the effects on the bass is very subtle. I may not have enough power to really enjoy what these could bring to the mix. I did not use the inductor, so I cant report on this. It would probably affect a 100 watters differently, in a good way.

And finally, as Tony (@talbany) mentioned while discussing the filters, you end up playing mostly on one setting that really sound good with the amp and the cab. Settings pushing the mids were usually the ones I preferred.

I would have recorded something, but I am not equipped to get a good capture of the sound and since you have to play loud to gwt the bass effects, it would distort or compress throught the phone.

It is a fun little project though

Cheers!

Fred.