Need help with Epiphone Thunderbird Pro IV bass preamp

[fhoefler1]

HI all,

I am new to Harmony Central and hope this is the right place to post about this....

 

I recently bought an Epiphone Thunderbird Pro IV and the preamp has gone bad. I bought a Seymour Duncan STC3a active preamp to replace it. Upon instillation I quickly realized that the main volume pot is "stacked" and subsequently to tall to fit in the electronics compartment of the bass. Furthermore, with all the pots in place, there is insufficient room for the preamp board itself. Does anybody have a recommendation for a replacement preamp for this particular bass? I have checked with Epiphone and they do not sell the part and could not recommend anything third party.

 

Thank you

[WRGKMC]

Welcome. I'll give you my 2 cents worth.

 

I think the bass might work with one of these Pro Z preamps. http://www.audereaudio.com/Pro_Z.htm

I don't know if the configuration is exactly the same but its got a similar module pot arrangement.

It may fit in there but haven't actually worked on one of those newer Epi Thunderbirds before, just the older Passive Gibson version.

 

There is a post that talks about the preamp and the setup looks similar minus the connector. http://forum.gibson.com/index.php?/topic/62347-thunderbird-pro-wiring-diagram/

 

I'd likely contact Epiphone support and see if that one would work or whether they can sell you a new module. Otherwise you'd have to pay a dealer to do it. That connector should make it easy to replace. Repairing the old preamp is another option. Usually you just have wiring issues with the jack, battery or bad pots that cause them to fail. The preamp is usually pretty simple in design. Some preamps are sealed in epoxy however making it impossible to repair them if you have components on the board that are bad.

 

Getting another preamp to fit can be very difficult. I've installed several preamps in basses but I usually a matter of cavity space (as you found out) I have one source that sells Artec preamps I've used before and done well with several of them but they don't have the fancy midrange shifting the Epiphone has. You essentially have a one two or three band EQ that also preamplifies. They are not drop in replacements either. They leave it up to you to add any additional pickup wiring and switching, so you need to have some electronics skill just to install them.

[fhoefler1]

Thank you for responding.

I had contacted Epiphone previously and they were no help. The Epiphone preamp they use isn't listed in their database and doesn't even have a part number (it is a warranty only item). The rep I spoke with was no help recommending anything either. I will contact Audere to get measurements before buying If I go that route.

 

The diagram forum you posted will be a big help as well!

 

Thanks Again