Effects in amp head.

[petemoore]

  Having only done this with smaller amps...
  Just looking for tips/advice/experience with fitting effects in amps.
  This would start off as an OD250 at the input jack area of a 'wide-deep layout' 18watt amp, and soon wish it had included reverb, perhaps verb too.
  So will require:
  power supply
  Connect AC supply to a 9vDc converter.
  effects
  They won't fit in with their existing boxes [1 RACO and 1 Holy Grail].
  It'd be nice to just lose the boxes.
  Any tips on any of this, advice on how keeping amp AC hashes out of the signal path..
  There is room left to plan in this amp at the input jack inside-chassis, and just above the input jack above-chassis platform [and other areas, it's a roomy amp.
  Seems like factory amps do this and just put the effect right on the Amp PC board.
     

[richon]

but the efecto would be used with relays also?

[petemoore]

  Oh yes, remote switching too.
  ...would have it's own set of issues.
  I suppose the signal would only that much more exposed to transformer 'air hash' as the circuit creates in additional wires [+boost effect].
  For some reason I think I should worry about enclosing them in separate 'container'.
  An improved question would be will adding Xformer and 9vDC line + effect board + effect routing w/bypass suffer with noise from being nearer the proximity of the HT transformer and current flows than it would on the floor.
  If so, how is it done in a way that makes it low noise like in clean/distort/channel amplifiers.
  I'm assuming layout can be made to acounts for 'everything' since the factory amps I have glanced inside showed the small signal components of the amp population all on 1 or more PCB's, there may have been shielding or ground plane or other protection I didn't notice.
  I guess I'm just thinking online and mulling it over, trying to form a future picture of how it'll work and where the problems will have been overcome [so as to incorporate solutions into the prototype 1], or whether the project would fail to overcome them.
 
 

[richon]

and making a chasis inside the chassis?  to crazy?

[Gordo]

and making a chasis inside the chassis?  to crazy?

Not really.  That's how high end stereo amps do it.  The power supply is usually walled or caged off from the main board.  I do a lot of service work on amps and most of the time the FX are on a daughter board with little more than a ribbon cable for all connections.  Just playing devil's advocate here, but are you sure you want to lock yourself in to the effects?  Maybe it's just my short attention span but I swap out pedals on my board constantly.  Seems like it would be easier to run them external even with a remote switcher.

[petemoore]

Just playing devil's advocate here, but are you sure you want to lock yourself in to the effects?
  Demonic advocation:
  Nope, not sure at all I wanna try this.
  In fact this thread is more of an inquiry into how it's done than whether I should do it.
  I see it in amps but never studied into it.
  I hear talk ''ah but it's a SS clipping circuit or element making the 'tube distortion' tone in that 'tube amp''.
  An Artist30 had very nice preamp Marshall-Distortion tone channel, it was not a problem at all with noise, so it can be done 'quietly', I just am not familiar enough with it to figure out where I can workaround [such as where I guess a built in amp SS-distort-circuit would be fed by it's own transformer tap/DC supply].
  Just wonderin' of those who have tried this kind of thing and encountered layout or noise troubles, or a way to approach it to avoid such troubles.

[maarten]

What I do in small amps where there is not much space available to separate the output transformer from the power transformer, is connect the output transformer to a set of headphones and move it around (after the power transformer and the rest of the supply circuit has been installed) to find a place where there is no hum. You might try this with any kind of transformer or inductor which picks up hum; you will find areas that are humfree (or the opposite) at places where you did not expect them - sometimes just changing the angle between the output transformer and the power transformer will induce (or cancel) hum.

Maybe this approach can help you, though I have not tried this with building effects in an amp. Probably the components will be less susceptible to pick up hum - or maybe you should connect the headphone to some kind of circuit which is known for picking up noises and move this around in your amp.

Maarten

[RedHouse]

I've actually done that, in my case I used 1590 type boxes in a manner reminiscent of the the way the cap cover on Fender amps is installed.

Drilled a couple holes in the top of the chassis for I/O and of course for the 4 corner screws then bolted the box onto the top of the chassis. The use then had to reach back behind the tubes to turn the knobs to set up the effect, but part the user liked was his settings never got messed with because they were out of harm's way. It was a lot of work and I really wouldn't do it again, but it was a good excersize in physical integration of the two systems.