I have posted before about problems that I encountered when using the LM4562 low distortion op amps, including most recently in the LM358 article in the Lab Notebook.
Just today, I stumbled across what may be the answer to the issue with that chip. It seems that the high value input resistor is not supplying enough bias current at startup and the chip latches. I have not tested this by lowering the value of the resistor, but I plan on putting the direct box pedal back on the bench to see what I can find.
Factoid: The cover of the guitar book is an actual scan of the back panel of my tweed Deluxe amplifier. The books turned out really nice and I hope that you enjoy using them.
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International Mail is coming back soon mostly dead. I can still send a Priority Envelope for $40 to $41 depending on the destination, but First Class mail of merchandise is no longer accepted for international shipping. I cannot even make a customs form for it using the USPS web site.
Sales to US addresses remains much the same with only a small postage increase. International ordering is still open but the postage rate is much higher, as listed above.
In a previous post, I showed how to use an SPDT switch to select between multiple memory chips on the Spin FV-1 to expand the number of patches available. In this post, I will show how to use a single DPDT switch to allow access to two memory chips plus the internal sounds that are built into the FV-1.
The extra set of poles on the switch allows the internal patches to be enabled when needed or disabled when the external memory chips are active. The switch needs to be a center-off DPDT, which is commonly available.
The middle pin of the left set of switch poles has a pull-down resistor and is connected to pin 13 of the FV-1. There are no other resistors or connections to pin 13. When the switch is in the middle position, the new resistor pulls pin 13 to ground to enable the internal sounds, and the other set of poles has disabled both external memories.
When the DPDT is toggled to either end position, pin 13 is made HIGH and the external memory chips are enabled as in the previous article.
This alternate bank switching method allows access to internal and external sounds with a single switch.
The Booster 2.5 was one of my early amp-in-a-box designs from about 1999. It has been used on numerous commercial pedal designs and as a starting point for the BSIAB and other similar designs.
I never knew this was a thing until I saw a forum post about it this week. Apparently it is the anti-boost, which means that the output can only be attenuated. Sounds easy enough… a potentiometer and switch in a box will do the job but can lead to loading problems and tone loss, so I quickly designed this circuit:
