5 band bass eq?

[fatfoohy]

Hello again internet!  Does anybody know of a good 5 band equalizer? i dont want it to be parametric and all the other fancy bells and whistles, if there isnt already a bass version, could somebody teach me how to convert it to bass(4 string, i have no ideas what frequencies i would need though) Thanks in advance!

[Taylor]

All the good info is here:

http://www.geofex.com/Article_Folders/EQs/paramet.htm

I would suggest building aziltz's 5-band parametric EQ project and putting trimpots for the frequency controls. Then you can set it internally to have ideal bands for your bass and taste, but you don't have to mess with the frequencies again if you're looking for something to set and forget.

[fatfoohy]

oof, sounds like a good idea, but i dont have the tools to make pcbs, I was hoping to perf it, and that'd be one heck of an undertaking.......any other ideas?

[fatfoohy]

Hmmmm.....looking at that geo fx article, could i just take out 2 of those bands and still have a full functioning effect? that would be ideal

[Taylor]

Yes, you could do that, but it would be close to the same parts count, still a large project for perf. Aziltz will probably make you a PCB from his layout.

[birt]

take a look at this schematic: http://www.albertkreuzer.com/pics/el/studiobass/schem/studiobass.gif

if you can find the right pots (50K linear with center tap) you can build the 5 band EQ from the fender studio bass. it sounds great and you can probably use a solid state driver instead of the triode.

oh and if you do find those pots, let me know :p

[Taylor]

Ok, but besides the hard-to-find pots, that circuit is using what looks like a big custom transformer as a group of inductors, right? Seems unlikely that you could get your hands on that. An opamp circuit like RG's is much more attainable, IMO.

[birt]

no it are seperate inductors. i can measure them if someone wants to build it.

[PRR]

> i can measure them

Why work? The values are ON the plan.

The "80Hz" inductor is marked RD-GRN-RD. Resistor code for 2500. But what units? Not H, there's no 2500H inductors. Not, as I assumed, uH, which is common in smaller coils.

2,500mH (2.5H) and 1uFd resonates at 100.7Hz. Not quite the nominal 80Hz but so close it is probably right.

And the "1,850Hz" coil is BRN-BLK-BRN, 100, assume mH. 100mH against the 0.082uFd cap resonates at 1,758Hz.

It would be good to know the Q; or rather the DC resistance. But off-hand I bet anything under 1K or 500 ohms will work. That's no real problem on the smaller coils.

We really want to know the current handling. 1mA may be ample.

None of these coils (maybe 100mH) will be stock at Mouser et al. Fender surely contracted for them.

The 2.5H might be found as a "2K 1W table-radio OT".

Some of these you may be able to wind with large-gauge pickup wire on a stack of iron lams from old wall-warts. Don't trust all-purpose L-meters for this. Use signal generator, 10K resistor AC voltmeter, and the cap value that Fender used, wind to get the specified frequency.

> hard-to-find pots

Frill. The tap forces a "flat" response when pots are mechanical center. It will work without the tap. 50K Linear is easy to source.

[Brymus]

Thats an interesting schematic,
It would probably make a one serious guitar amp if it were tweaked right.

Whats with the center tap off the B+ winding hitting that (voltage divider?) ?
Is that to lower the B+ ? I have heard/seen using zeners in series with the center tap to lower the B+ but never a network like that.
Also thats the first Fender tube amp I have seen with snubbers on the bridge rectifier.
And the first schematic with a 12AT7 run at 400v on the plates (a voltage follower driver stage ? )
With an SS rectifier and those plate voltages that amp probably sounds nice and punchy

[birt]

it's a good amp. i have those coils (from a super twin reverb) and will probably make the EQ as a standalone unit.

[gjesse]

I know this thread is more or less dead, but I'm looking for help with my Fender Studio Bass's 5 band Eq.  The 1850 cuts and boosts, the rest just cut...no boost.  Any ideas what the faulty component(s) might be?