Anderton Tremolo: alternative to the CLM6000?

[Bucksears]

I know there's been a million threads about this, but some folks just ask (in general) what to substitute in its place rather than say what circuit it's going in.

Mark Hammer once suggested the Silonex NSL-32 for the Anderton Phaser - would that also apply to the Anderton Tremolo at GGG?
I built one a few years ago for my cousin and it wound up being a worthy competitor to the one in my Super Reverb. I got a CLM6000 from Smallbear at that time, but Steve is down to the 'slightly out of spec' ones now. I might just pick up one of those, but if there is another working replacement that I could try, I'm all ears.

[caspercody]

Found this on the other forum:

You can make a component similar to a CLM6000 fairly easily,here's all you need :

1X 5mm LED,can be red,green,or yellow.
1X LDR/Cadmium Sulphide Cell (the one I used had a dark resistance of 10M,light resistance of about 300 ohms).
Some black Heatshrink tubing(opaque) large enough to easily fit over the LDR and LED.

Some red hookup wire.
Some black hookup wire.

Stanley knife blade.

Source of heat,eg: A soldering iron.


Method:

1-Strip some insulation off the red and black hookup wire,put some of the red insulation on the LED's "anode (A)" terminal,put some black insulation on the LED's "cathode (K)" terminal,about 20mm long in each case.

2-Use a couple of pieces of black insulation for the LDR,20mm long,the pieces of insulation can be the same colour since LDRs are not polarized.

3-Cut a 20mm piece of Heatshrink tubing,and slide one end over the LDR,next slide the LED into the Heatshrink tubing,try and get both the LDR and the LED to meet in roughly the middle of the Heatshrink Tubing.

4-Next,making sure that the LED's terminals are inline with the LDR's,heat the Heatshrink tubing so that it seals the LDR and Led up inside.

5-Finally use a blade from a Stanley knife to carefully trim off the excess heatshrink tubing,not too much otherwise it will all come apart.


Voila!!!....one home made CLM6000 substitute...

[Bucksears]

Thanks - I'll give that a shot!

[bosleymusic.com]

I would check the spec sheets for Vactrols to find the one that most closely matches your purpose. Homemade LDRs tend to be more inconsistent than the already inconsistent manufacturing processes of commercial LDRs.

[Mark Hammer]

Craig relied on the CLM6000 back in those days because the ON and settling time of that unit complemented his design intentions.  If you can find an LDR that has similar properties (reasonably fast on  time, and slightly sluggish resettling time) and is either in the same resistance range or has a function in the circuit whereby other components can be easily tweaked to get the same response as a 6000, then a homebrew is just as good.

Of course, there is no reason why you have to like the same time-constants that Craig liked.  If the on and off times are agreeable to you then all you need be concerned with is the resistance.

[midwayfair]

I just picked up a ton of LDRs and optocouplers from Smallbear, including some of the 6000s. I plan on testing them all shortly.

However, just on basic specs, I'd say the VTL5C3 is pretty close if not indistinguishable in a tremolo.

[amz-fx]

Yes, the NSL-32 is almost an exact duplicate.

Check my blog for a comparison of the specs.

regards, Jack

[R.G.]

If you're willing to take pot luck, Electronic Goldmine has some very inexpensive units that have worked well for me in the past. Don't know what their stock is like now. They're listed as "audio optoisolators" I think.

I vaguely remember a recent sale on them for $0.39 each, down from the normal $1.00.

[Mark Hammer]

If we were talking about LDRs that have to respond quickly, in things like limiters, noise gates, compressors, or even auto-wahs, response time would be important.  But for tremolos - unless you absolutely positively HAVE to have a pure square "chop" - most LDRs/optoisolators will suit the Anderton circuit, and the range of speeds it employs.  If you need modulation rates in the audio range (for ring-mod-like sounds) then I'd recommend a different design than the Anderton one.

The nice thing about that circuit is that it can accommodate a very wide range of LDR values.  If the value isn't particularly close to a CLM6000, it is a simple matter to adjust some of the other component values around the op-amp to achieve the same tremolo depth.