Recent content by aquataur

More anomalies: Butler produces in the stage that drives the "distortion generator" (=tubes) a heavily low passed signal. Look up Madbean's Archibald schematic. A 500k drive pot together with a 120pF cap yields a 2.6kHz treble rolloff. The Cattle Driver uses 50k and 50 pF (63 kHz). If you scale...

Upon second (or third) thought... C11 can be replaced by a bridge. There is blocking caps all over the tonestack. It looks like this arrangement stems from an earlier design stage, where it was needed. I tried it and it works. I also referenced C19 to ground with correct polarity without detriment.

Good readings. C19 is 1µF, ok for a polyester cap. But C11 is 4.7µF - I need a bigger enclosure. Analog Devices Design note SLYT796a-1: Selecting Capacitors to Minimize Distortion in Audio Amplifiers says: (page 4) Note that they speak of "anode" and "cathode" (as mentioned above). When the...

Great. So this can be fixed on the commercial PCBs too. The version I sketched works very well too. It is incredible how quiet this circuit is with that amount of clipping. Switching is very quiet too. Thumbs up! Edit: the bass knob BTW is very usable, and indeed needed.

I did not find a thread that this question would fit in so I opened a new one. Admin please move if in the wrong section. I just looked through the Cattle Driver schematic. I noticed that C19, which is in the ground leg of the output stage's feedback node, appears in the wrong polarity. If the...

I made one of those. Great sounding unit. Is it dumble-esque? How can I know? ;) During the make, I observed the following things: the dynamics pot will have the wrong sense of rotation as per the kit schematic. This is annoying, since we are used to CW=more of something. so is presence, but...

Exactly. Try it. I suppose you can even tinker up a makeshift "cable" that does this. 1k sounds very small, I always used higher values. A typical pickup`s DC impedance is about 5-6kOhm. Try a 10k. This way your driving circuit becomes more of a current drive. Others have suggested 50k, but that...

Certainly. I try to say it in my words, since I am no specialist in this field. The stability of the feedback loop depends on the quality of the fed back signal phase-wise. This is ideally 180 degrees or does not deviate much from it. Logically, 0° feedback is feed forward - a perfect...

I have always used buffers whenever they seemed advisable - which was often the case. A buffer is just a circuit that relieves the preceding circuit of any load, while (ideally) not imparting any sonic signature of its own. It is a gross misunderstanding of what is going on if people think they...

That's what they do... (NJM4558/4559 Datasheet by New Japan Radio Co.) Usually such datasheets are full of praise how superior their unit is compared to X, but this one lets you think this is just some matched 741's.

Removed. OT.

Hi Chuck, any new insights on that? I looked up the 4559 OPA and was quite astonished not to find any high-bred unit as is customary today (needlessly). This is rather two 741's in a package. A stone-old operational amp. I guess any similar bipolar unit from that era (read: similar bandwidth...

That is not uncommon. Jack Orman has been going on about this at length. Many patents aren't worth the paper they are printed on. I have encountered at least one patent to do with stomp boxes that was wrong on a small, but critical point. It is close at hand that this was deliberate, in order to...

This is the way I see it. It is just a view, one of many views. Any view is just a snapshot of reality, one facet of an endless number of possible facets. It is just a subjective perception without claim of truth. As such anybody's perception is subjectively true. The writing serves the sole...

Please elaborate. I am all ears.