coupling cap to block some bass?

[dmartn149]

Actually, I've been playing it through a 12" Celestion too. It's a G1265 in an open back cab. It sounds a lot like the 8" jensen but bigger (not just louder) So now I'm thinking of adding an extension speaker jack on a new back panel, and store the original panel. It looks to me like with a jack like this
http://www.switchcraft.com/Drawings/13e_cd.pdf
I could have the internal speaker disconnect when I plug an extension into it.
I don't know, I'm not sure I'd ever use it that way anyway. I'll just use as is for now.

PS Thanks again to all for the excellent advice.

[lowell]

I'd keep reducing the bypass cap values and coupling cap values. Like in mixing audio...if you have to turn the damn knob backwards to make it sound good, then it IS good. Don't be afraid to go extreme. You can always undo it. You could even add a switch for these mods so you can switch the low end response whether using single coils or humbuckers. Also, larger filter caps can tighten low end, though that may or may not be noticeable through your speaker if it's not handling low end well in the first place.

[Dave H]

Okay, I've tried a couple of different cathode bypass caps on the first stage. I'm down to 1uf there, and also changed the last coupling cap from .02uf to .01uf. I still can't get a good sound using neck pickup on any of my guitars. Should I just forget using the neck pickup with this amp? It sounds great with a bridge position humbucker. Maybe that's it's one trick.

The first stage cathode bypass cap can only roll off the bass by 6dB max and the last stage coupling cap is inside the output stage feedback loop which reduces the effect of a lower value cap. I'd experiment with a lower value coupling cap between the first stage plate and vol pot. The bass roll off there is 6dB/octave. It's not limited to 6dB max like a cathode bypass cap. If the vol pot is 1M, try 1n, 2n2, 4n7 etc. caps and then fine tune the value to find the best compromise for the bridge and neck pickup.

[dmartn149]

Thanks Dave. After re-reading this thread, I realize that that is what pdf64 recommended too. I guess I got a little confused, and kept trying to work with the cathode bypass cap. I'll concentrate on that first stage coupling cap now. I may have to order those caps though, Ill check into that today.

[dmartn149]

Okay thanks to everyone who gave advice on tweaking the bass response on this amp. I have a .0022uf cap for first stage coupling now and it still doesn't sound great with a neck humbucker. It sounds so awesome with a bridge humbucker though, I think I'll just leave it the way it is now. Truth is, I don't usually use the neck pickup anyway. But thank you all for helping to educate me just a little more.

Dan