When did the DRRI tremolo circuit change?

Dan

Hi, I'm looking at getting a drri pretty soon. Just wondering if anyone knows when they changed the tremolo circuit? Has anyone got any experience of the newer circuit? Better? Worse? Cheers

ICBM

A few years ago, although I'm not sure of the exact changeover date. New ones are much worse - bad enough that I would avoid one if you like the tremolo normally.

This is the new version with the solid-state coupler unit (lower right, with the cable loom going to it) and the power supply for it (far left):

http://uraltone.com/info/wp-content/uploads/2009/08/fender_deluxe_reverb_2.jpg

You can tell from the outside, if you know where to look - the solid-state circuit board is held by brackets and two screws directly behind V2 and V3 on the underside of the chassis. This picture shows where the screw holes are (the board has either been removed and the opto-coupler fitted, or there was a transition period where Fender used the new chassis but fitted the original coupler for a while):

http://www.pnelectronics.com.au/Uploads/Images/fender-deluxe-reverb-65-reissue002.jpg

The two holes are in the upper left of the picture. If you run your finger under the chassis and feel two screw heads here, it's got the solid-state circuit.

Dan

ICBM I was hoping you would reply, this is awesome info! Thank you sir!

Would it be worth while and cost effective for a tech to try and reverse? Does the newer solid state circuit deal with the ticking tremolo issue?

ICBM

It's very easy to reverse - you just remove the two circuits, the cabling and all the other crap associated with them, and install the small black component which looks like a toffee wrapper almost in the middle of the amp in the lower pic . (Also known as a 'bug' or 'roach' because older versions looked a bit more like some kind of insect.) It's actually an opto-coupler - a neon bulb and a light-dependent resistor wrapped in a piece of heatshrink tubing. The LDR contains chemicals which are now prohibited under RoHS regulations, so they designed that whole complex mess of solid-state circuitry to replace it! 

Barmy. It would have been much better to just accept that the exact DR circuit is not possible to produce legally now (since it isn't exact with all that extra stuff anyway, even if you accept the completely different construction of the reissues) and redesigned it for bias mod tremolo like a Princeton.

The solid-state circuit doesn't entirely cure the ticking either, because some of it comes from the oscillator valve via the power supply.

Dan

Great stuff. Thanks very much for your help.

mellowsun

Ditch the amp's tremolo and use the awesome Delta-Trem valve-driven pedal from Effectrode if you want the authentic sounding effect.

Dan

Nice but ooh man thats pricey.