Reverb with MN3011

[fuzzo]

Hi guys,

I'm trying to fix a old Guyatone reverb pedal (adx tube) but I'm wondering if I'll acheive it. (The pcb is very tight and fragile) I'm thiking about taking off the  MN3011 and its clock driver form the PCB and make another reverb circuit if I give up the fixing of the pedal.

Do you have any advice to remove  the MN3011 form the PCB ?   things to don't destroy it (it costs a lot of money , so I'd prefer :lol: )

advices/ideas about the design of the circuit ? I'm planing building it with the datasheet circuit appliation in mind and old document called "soldistate reverb".

thanks. 

[Hides-His-Eyes]

If it was me I'd totally destroy the PCB with a rotary tool until each leg was attached only to a single PCB pad, and then do them one at a time, allowing the chip to cool fully in between.

[Mark Hammer]

I have the schematic for it, and it's a pretty complex circuit with a lot of great parts on board.

It might be worth it to repair.  But if you decide against that, you need to do yourself a favour and remove all those parts with care, rather than  attack it with a dremel for the one chip.

If you don't have some solder wick and liquid flux, consider getting some.  VERY helpful when desoldering sensitive parts.

As solid-state reverbs, MN3011 circuits came and went pretty quick.  I suspect mostly because folks never really put much thought into how to use them properly.  Looking at the ADX schematic, it appears Guyatone didn't really do much more than any of the other manufacturers did.  For example, the 6 outputs are mixed in equal proportion< without any differential filtering< and that"s not how reverb works.

[fuzzo]

thnaks for you answers.

No I don't have a  solder wick and liquid flux (I don't even know what they're :lol: ) , I just have a solder sucker .

What things do you consider interesting in the guyatone ? (the things I wonder it's the tube inside the box . Is it really used with a so low voltage (12V) ? )


by the way , about the guyatone , it just returns to life :lol: I just bypass the Compador/expandor , I have sound but with lood background noises.

[fuzzo]

For example, the 6 outputs are mixed in equal proportion< without any differential filtering< and that"s not how reverb works

Could you explain more about that ?

I know it's not a topic about the guyatone (I already  made one about the fixing). But I got something weird with. the repeat pot. gives only 1 reapeat or 4 (depending of the "mode" ) even when I change thevalues of the pot's resistor.

[Govmnt_Lacky]

No I don't have a  solder wick and liquid flux (I don't even know what they're :lol: ) , I just have a solder sucker .

IMHO... a solder sucker would be MUCH BETTER than solder wick. With the solder sucker, you only need to leave the iron on the pins for a minimal amount of time to heat the solder and use the solder sucker to remove it 

With the solder wick, the iron would be on the pins for a LONGER period of time to allow the solder to flow onto the wick. This greatly improves the chances of overheating the IC 

My 2 pennies!

[Mark Hammer]

For example, the 6 outputs are mixed in equal proportion< without any differential filtering< and that"s not how reverb works

Could you explain more about that ?

I know it's not a topic about the guyatone (I already  made one about the fixing). But I got something weird with. the repeat pot. gives only 1 reapeat or 4 (depending of the "mode" ) even when I change thevalues of the pot's resistor.

Sure.  Stand in a room and yell.  Early reflections are louder and generally have more top end than later reflections, partly because top end is that part of the acoustic signal most susceptible to being "eaten up" by bouncing off multiple surfaces, and because bouncing off surfaces to arrive at your ear later means the entire signal loses energy.  In some respects, I suppose one IS moving in that direction if all 6 taps are mixed equally, and the regen loop provides additional filtering such that each repeat of all 6 is progressively duller and quieter.  But the more realistic approach is really to treat taps at the shortest delay as if they were coming from a hard reflective surface (no filtering and no attenuation), and later ones as if they were coming from more distant softer surfaces (less treble, less amplitude).  Treating them all equivalently strikes me as likely to yield "un-natural" sounding electronic reverb.  Not quite as bad as a single-tap BBD, but not dramatically better.

[fuzzo]

Thanks Mark ,

so playing with the resistors of each delay outputs will simulate this behaviour ?

by the way, the pedal is working , I ve it on my pedalboard since few days, (it becomes really noisy only if I increase the delay time , I din't put the NE571 yet) sounds cool .