Old School depth

[Aentons]

Hi folks,

I just finished up the Old School and it sounds great. However, the Depth knob doesn't seem to kick in until at least halfway up. I know VFE stuff tends to have some extra range on the knobs. Just wondering if this in particular is normal?

[bsoncini]

I don't know if it is normal but mine is the same.

[gordo]

Me too

[madbean]

You could change the response by switching to either a 1MB or 1MC. With a 1M B or C the depth change will onset earlier. The trade-off is that there will be less depth change in the second half of the pot rotation. It's really a matter of taste. You could also change it to a 500kB but that might decrease the maximum depth available somewhat.

[Aentons]

Do you think he used a custom pot in his productuion builds?

[Aentons]

Also, the speed range seems to be kind of mediocre as well... Not too fast, not too slow.

This is my first Tremolo and I don't know jack about the EA, but most other tremolos I have heard (I think) go faster and slower.

I am slightly underwelmed with the speed/depth controls/range since the VFE description says "Derived from a rich sounding, but feature-limited tremolo circuit from the 1960s, we added extra range to both speed &
depth controls".

Sorry to vent... It sounds really good, but I had high hopes to be blown away with options on this one. I'll try and fiddle with some values. I'm a little confused at exactly what to tweak for the speed as well. Thanks for the input folks

[madbean]

Perhaps this is just not the tremolo for you (hey, it happens). I do suggest checking out a demo or two on youTube for comparison to make sure you are getting the similar results on the speed and depth controls. And, also double check to make sure you've used all the right values on the LFO section just in case.

As far as a custom pot, no. AFAIK the only custom 1MA pots he used on any VFE builds were 10% tolerance instead of the normal 20% on generic Alphas. The tighter tolerance would not change the overall range of the depth control in this case.

[Aentons]

I do like the Old School alot and I did watch a few demo videos. It just didn't occur to me until I finished building it that, out of the box, it may not be quite as versatile as what I had in my head. The old version even had a fast/slow speed range  switch, so that's probably what threw me off. It really is a very good and versatile pedal.

The only thing that is not on par with the demo videos is the Depth taper. I don't have a B or C, but I actually do have a 1MD pot that came from Peter that I thought about trying but I'm am thinking it will just make it worse. Seems like a K taper might do the trick if such a beast exists

[Aentons]

Ok, I verified values for everything and the only thing out of the ordinary is that I used 3 different Nichicon electrolytics for the seven 22uf caps. See pic. The only one that looks like it would affect the LFO is C23. Is that the one to the left of the 4580? I used a low profile there.

[midwayfair]

C23 is the envelope hold capacitor. It does not affect the LFO unless you're using the envelope feature.

This is my first Tremolo and I don't know jack about the EA, but most other tremolos I have heard (I think) go faster and slower.

Most tremolos don't use this type of circuit anymore, because it's limited. It's a single-transistor circuit based on a single-tube circuit, called a phase shift oscillator, and there's a limit to how much speed and depth you can gey. There are threads around that will delve into the technical details.

The limited depth and speed are the price paid for actual sine wave oscillation, which is much, much harder to get out of other low frequency oscillators (especially analog ones -- digital is a little more up to the task).

The depth can be manipulated in the following ways:
1. R10 forms a voltage divider of sorts with the oscillator output. It's 10K out of 1,000K, so you can imagine how much effect that might have. However, you can try lowering it.
2. The 2N5457 controls the gain of the amplifier stage (the dry path). It will bottom out at about 300R. You can choose a lower gain FET, like a 2N5459, which will bottom out at about 100R, which is not insignificant but not exactly an order of magnitude difference. However, the same voltage that drives the 2N5457 to a higher resistance will not drive the 2N5459 as far up. In other words, you can get more "on" gain in exchange for less "off." I'll leave it to you to decide if desoldering the FET and ordering a bunch to test is worth the effort. You only have 9V total to play with, and you're getting almost all of it out of the oscillator, so the FET's characteristics entirely determine the full decibel range of the circuit.

The speed can be manipulated in the following ways:
1. You can socket R1 (and possibly R13). You may be able to get it to run very slightly faster, or you might just have a setting at the top of the speed pot that kills the oscillator.
2. R14 can be increased and you'll get more slow speeds. You may have to change R1.
3. C7-9 control the phase shift. Smaller capacitors will make the whole thing go faster. Larger capacitors will make the whole thing slower.

In any case, as I mentioned above, there is a speed limit on the circuit. You can't get arbitrarily slow or fast speeds at the same time. You can pick "everything's faster" or "everything's slower" but not both with this type of oscillator.