Thunderbird Club

[JIO]

that PBass and the portaflex look Sooooo tempting! Jeaolus...

I love PT 50s. Again, 7027s one of my favorite power tubes. Some claim that (P into Ampeg B-15) is the most recorded setup in music history. Then read Magnatones are really the unsung heros. dunno...
The B-15 is a superb sounding amp. I like to modify them with a SS rectifier. They sing like that..

I've heard that every studio of worth across the country has an in-house B-15 as a matter of course. They were made for 20 years so there's probably still a lot of them out there. I was lucky and got mine for a reasonable price right before Ampeg re-introded it as the Heritage series in 2010. The month after getting it had the new B-15N featured on the cover of Bassplayer magazine and prices shot up for originals. So what does modifying with a SS rectifier do? Pics?

 

[tbird42]

How long have you had it and have you had this problem before with it if you've had it a while. I'm still thinking it's an external thing

I've had my Epi for about 3 years, and I remember kind of noticing it for the first few months but not thinking much about it (I used to be much less committed to learning and practicing). Then after my band was more active, I got more into it and as I stood more and moved around it became more of an issue. Me and my dad looked at it inside and out but could not figure it out, so I just settled for the sponge, which has so far worked pretty well. So I wouldn't say it's resolved, more that it's just not as much of an issue now.

 

[theFixer]

Does the control plate have shielding paint on it? If so, is it grounded?

My Epi 'bird had foil tape on the inside of the cover. It was all dug up from the tip of the over-sized jack. That was how I figgerd out what was goin' on with it

 

[Christine]

I've had my Epi for about 3 years, and I remember kind of noticing it for the first few months but not thinking much about it (I used to be much less committed to learning and practicing). Then after my band was more active, I got more into it and as I stood more and moved around it became more of an issue. Me and my dad looked at it inside and out but could not figure it out, so I just settled for the sponge, which has so far worked pretty well. So I wouldn't say it's resolved, more that it's just not as much of an issue now.

Do you have access to an electrical meter? Circuit/voltage/resistance etc.?

 

[tbird42]

Do you have access to an electrical meter? Circuit/voltage/resistance etc.?

My dad will probably have one somewhere, yeah

 

[tbird42]

My Epi 'bird had foil tape on the inside of the cover. It was all dug up from the tip of the over-sized jack. That was how I figgerd out what was goin' on with it

My shielding isn't exactly dug up as you put it but I notice it look a little wrinkled. Here's a shot of it and my wiring in case anyone can spot a big red button solution I've been missing.

 

[Christine]

No grounding at all to the cover? It does look like it's got a foil backing too

 

[Chucky Stiletti]

My shielding isn't exactly dug up as you put it but I notice it look a little wrinkled. Here's a shot of it and my wiring in case anyone can spot a big red button solution I've been missing.View attachment 3106891 View attachment 3106892

I think we found your problem. I asked about amps because many vintage amps don't have a dedicated groung connection to the plug. They instead shunt all grounding to the neutral. This makes for less than optimum grounding. Clearly not the problem
The foil on the back of the plate is not making contact with any ground. A piece of copper tape soldered to the case of one of the pots and run all the way up to the recess for the plate (usually underneath one of the svrew holes for the plate) should cure your problem.

 

[tbird42]

No grounding at all to the cover? It does look like it's got a foil backing too

I suppose not, is that usually standard with most basses?

 

[theFixer]

I've had my Epi for about 3 years, and I remember kind of noticing it for the first few months but not thinking much about it (I used to be much less committed to learning and practicing). Then after my band was more active, I got more into it and as I stood more and moved around it became more of an issue. Me and my dad looked at it inside and out but could not figure it out, so I just settled for the sponge, which has so far worked pretty well. So I wouldn't say it's resolved, more that it's just not as much of an issue now.

(Please know that this is not intended to be insulting or incendiary, just a honest effort to help you sort out your issue)

It just occurred to me... if everything is as it should be inside your control cavity, nothing should be making contact on the inside between the cover and the wiring/components. This means that any current built up (static or otherwise) shouldn't be able to pass through into your signal. I'll urge you to pull that cover plate & see if there's any evidence of scratching, arching, or any other such maladies, and carefully check to make sure all wires & components are snug, and a safe distance beneath the cover. While you're in there... it's a good idea to check all solder points as well (whether you are the original owner or not... sh!t happens).

Hope this helps!

 

[tbird42]

I think we found your problem. I asked about amps because many vintage amps don't have a dedicated groung connection to the plug. They instead shunt all grounding to the neutral. This makes for less than optimum grounding. Clearly not the problem
The foil on the back of the plate is not making contact with any ground. A piece of copper tape soldered to the case of one of the pots and run all the way up to the recess for the plate (usually underneath one of the svrew holes for the plate) should cure your problem.

Thanks a lot, I'm relieved that my fashion choices weren't interfering with my onstage playing.
Although I'll probably still tape a sponge to it for sentimental reasons...

 

[Christine]

Thanks a lot, I'm relieved that my fashion choices weren't interfering with my onstage playing.
Although I'll probably still tape a sponge to it for sentimental reasons...

What will you be taping a sponge too?

 

[Chucky Stiletti]

I've heard that every studio of worth across the country has an in-house B-15 as a matter of course. They were made for 20 years so there's probably still a lot of them out there. I was lucky and got mine for a reasonable price right before Ampeg re-introded it as the Heritage series in 2010. The month after getting it had the new B-15N featured on the cover of Bassplayer magazine and prices shot up for originals. So what does modifying with a SS rectifier do? Pics?

As with any tube, the plate of the 5AR4 rectifier tube will saturate on higher power transients and "sag".
So as not to derail this is better discussed via PM?

 

[theFixer]

My shielding isn't exactly dug up as you put it but I notice it look a little wrinkled. Here's a shot of it and my wiring in case anyone can spot a big red button solution I've been missing.View attachment 3106891 View attachment 3106892

Yup... yer foil looks good. The second shot's a little fuzzy but hell... so am I

From what I can see in the pic... it doesn't look like anything should be touching that cover plate, which means that there's no real way for a static charge to pass through the cover & get into your sound. Hhmmm...

 

[tbird42]

What will you be taping a sponge too?

The back of the plate, I'm embarrassed to admit it but I've had the same sponge taped on the bass for about a year now with some light tape.
I'm no idiot though, I only use tape that won't strip the finish!

 

[Christine]

As with any tube, the plate of the 5AR4 rectifier tube will saturate on higher power transients and "sag".

Am I in a Star Trek thread, I'm sure Scotty said that at least once every two shows

 

[Chucky Stiletti]

Yup... yer foil looks good. The second shot's a little fuzzy but hell... so am I

From what I can see in the pic... it doesn't look like anything should be touching that cover plate, which means that there's no real way for a static charge to pass through the cover & get into your sound. Hhmmm...

could be anything but bad jacks will crackle and pop..

 

[Christine]

The back of the plate, I'm embarrassed to admit it but I've had the same sponge taped on the bass for about a year now with some light tape.
I'm no idiot though, I only use tape that won't strip the finish!

The bass, Thank God for that!

 

[JJR58]

Do they usually come out at night? If so what have you been doing at night? You wouldn't be too pissed (drunk) to notice?

Nobody wants to know what I do at night.

 

[JIO]

Blurry pic of the guts but mostly everything seems normal - the cover shouldn't have anything to do with it. Some basses (like my '66 P) don't have a ground-wire to the jack but works fine with no issues. It's an easy enough chance-fix to see if it eliminates your issue. Star grounding will eliminate electronic hum/buzz but static is something I've never encountered.