Rivera Fender Concert mods

[merkaba22]

Originally Posted by jay42

You'd best call your tech on those measurements. Mine is not 22.25" wide. Also the chassis has...what to call it...the rear lip that takes 3 woodscrews, so it needs a deeper cabinet than the normal BF/SF amp.

The FFG shows the Fender head case as 23 5/8"W x 10 7/8"T x 11 1/4"D. I agree that those look too tall. Anyway, 23 5/8" - 1.5" = 22 1/8"...which is what I recommend for the interior cab width, so you aren't scraping tolex all the time.

Thanks jay42 -- you are right, 22.125 is the correct size of the chassis -- I was unclear by calling 22.25; I was working off my notes from a few months back and I think that was for the cab inner dimension so that the chassis would avoid scraping tolex. Maybe 22.1875 would yield the 23.625 given that the true size of the 3/4" stock material and the tolex is collectively less that .75 -- close fit, one way or another!

I am aware of the rear lip and I suppose that's in part why the cab depth is called at 10.875 whereas replacement cabs I mentioned above are usually only 9.5.

[merkaba22]

When to see the tech; the exact sizes of the chassis is 22 x 9.5 x 1.75.

Lopoline is making the headcab with a 9.5 height and 10.5 depth -- there's enough room between the cap pan and the front grill for the reverb to be placed sideways and allow for my Eventide Time Factor, midi-switcher and Voodoo Labs power supply to be on the cab's floor as a type of installation, etc..

This is good.

[VicLesnaik]

Wondering how to reduce the tone suck when using the stock channel/reverb switching pedal. Any ideas?

Also wondering if doubling (adding a second) 250 pf cap to the clean channel treble control would in fact increase sustain and add mids. Insights?

[stratopastor]

... so there's tone suckage, with the footswitch, on the Concert? I knew that was true for some Princeton Reberb IIs... on that amp I believe it's something to do with component tolerances and the nonzero/noninfinite resistance of the optocouplers.

[debarton]

So I just got my amp back from the shop and it turns out that the problem was just bad power tubes. No damage to the amp. They did put in Mesa tubes without asking me, though. That's a little like painting someone's bedroom without asking them what color they want it, but they seem to be fine. 42 bucks for tubes, 60 bucks in labor (amp needed biasing). I just bought a Warehouse EG-65 that I'm about to install, but I have a question:

Which wire is positive? White or black? I forgot to note it when I removed the old speaker.

[jay42]

Originally Posted by debarton

...I have a question:

Which wire is positive? White or black? I forgot to note it when I removed the old speaker.

Pop the F cap off. The center is positive.

[debarton]

oh duh. sometimes I am really thick.

[VicLesnaik]

Got my mods done and sounds great!
However, I have signal breaking up when I put a unit in the effects loop and think it is the from output circuit ... any ideas?

[VicLesnaik]

Still loose tone when plugging in the footswitch for Reverb and Channel switching.
I suspect the cable length might be where the signal looses strength.

Also would like to wire up the reverb switch on the footswitch to take the tone circut out of the second channel ala Dumble . I never switch the reverb on or off but just leave it on or off.

Help ... anyone ..

[jay42]

Originally Posted by VicLesnaik

Still loose tone when plugging in the footswitch for Reverb and Channel switching.
I suspect the cable length might be where the signal looses strength.

Also would like to wire up the reverb switch on the footswitch to take the tone circut out of the second channel ala Dumble . I never switch the reverb on or off but just leave it on or off.

Help ... anyone ..

Do you have the original switch? I built my own and frankly, I don't hear a difference. It has multiple twisted pair
with a shield and foil. I don't recall the brand. It's on the order of 12 to 15 feet long.

[VicLesnaik]

Why yes it is the original switch ... were you able to use your switch for just channel switching? If so all I'll need to do is wire up the reverb switch in my pedal to drop the tone circut and still use the same switch.

[Ronsonic]

Originally Posted by VicLesnaik

Got my mods done and sounds great!
However, I have signal breaking up when I put a unit in the effects loop and think it is the from output circuit ... any ideas?

Overdriving the effects in the loop?

[Blue Strat]

Originally Posted by stratopastor

... so there's tone suckage, with the footswitch, on the Concert? I knew that was true for some Princeton Reberb IIs... on that amp I believe it's something to do with component tolerances and the nonzero/noninfinite resistance of the optocouplers.

Yep, off isn't high enough resistance and on isn't zero resistance in many cases. This leads to tone suckage.

[VicLesnaik]

Originally Posted by Blue Strat

Yep, off isn't high enough resistance and on isn't zero resistance in many cases. This leads to tone suckage.

So is it a case of changing resistance and if so, how to go about doing that.
I'm in the dark with optocouplers and don't know how I could mod the circuit to use relay.

Cool getting through my mods so far and great to find so much info here.

[jay42]

Originally Posted by Blue Strat

Yep, off isn't high enough resistance and on isn't zero resistance in many cases. This leads to tone suckage.

In these amps, the front panel channel switch, controls the LDRs. It does not bypass them and the audio signal does not got to the footswitch. The reverb footswitch switch, however, is just like any old BF where the signal goes out the switch and comes back when it's on.