This was a really fun board to put together. Combination vocal and keys effects chains. “Mooged” out with a tour case customized SKB pedalboard. George L custom cables tie it all together!
I had a customer request for a circuit to make an older 18 volt chorus pedal more pedalboard friendly.
So i whipped up a simple, useful circuit. 9vdc to 18vdc charge pump.
Using a LT1054IP IC, a few caps and 1n5819 Schottky diodes, this is designed to take 9 volts DC and step it up to the 18 Volts that the pedal wanted to see.
The Schottky diodes have a very low voltage drop, thus allowing the voltage to remain close to 18V even under load. 17.8 (You could also use 1n4148 without any issue, but the resulting output voltage would be a bit lower due to the forward voltage of the diode)
Just off the bench:
I had a customer with a pedaltrain pedalboard. He had spent quite a bit of time selecting the pedals he wanted and contacted me about neatening and solidifying the overall board
Here is the before: all the power cabling was on top of the board and a lot of stuff was floating around.
After: cleaned up wiring, solidified pedal velcro, and added a few cables to connect it all together. Super solid and looking (and sounding) great
A little maintainence on a personal amp of mine. I acquired this in rough order. It had been used very lightly and had sat in an attic since. As so, every electrolytic capacitor In the amp was not up to spec. Most notable, the main filter node in the cap can had failed completely. All the tubes were original, and still test strong.
Here’s a picture of the schematic that was inside this particular amp.
After replacing a few burned out bulbs, the acrylic logo came back to life. I also updated the stock power cable with a 3 prong.
I recently came into this pedal in non-working condition. All original 1978 grey box DOD 250 overdrive preamp
Bypassed signal was fine, but the unit had no drive output. Switch and voltages checked out ok, so I dug out my signal generator and oscilloscope. Trace signal was getting to the input of the op amp, but the amp had nothing on the output.
I opted to add a socket when I removed the old UA741CP. This will make experimenting with different chips a lot eisier in the future!
I replaced the op amp with an SK equivalent SK3552 (made in Italy) that I had on hand. Now this thing sounds awesome! Ready to rock for another 35 years
This pedal didn’t come in with any particular complaint, just wanted a checkout for general health. And it passed with flying colors! I checked the caps for leakage, cleaned and tightened the jacks and pots. All good to go!
Here are a few circuit shots for those like me who love that sort of thing 🙂
On the bench, we have a 2004 American Standard strat in for an S1 switch modification. For this project we will be using the stock American Standard pickups. Whenever I’m working on a fairly major rewire like this, I will remove the pickguard from the instrument to work on it. (Desolder the jack wiring and bridge ground) Here we have the stock American Standard wiring.
The S1 Modification require a 5 Way Super switch (Fender Part number 099-2251-000) And the S-1 switching pot (Fender Part number 007-8777-000) As a note, they make 2 different versions of this switch. This one has a small knurled tip that is meant for the strat. The Tele/P-J bass has a smooth brass shaft which is longer
All Wired up and ready to go; Look at all that extra wire! As a note for those doing this on your own, pre-solder the wires and the eyelets on top of the switch. That will make your life much easier when you put it all together!
For those of you looking for a DIY Diagram, this one is quite clear (Thanks to Andybighair over at the Fender Forum) As a note, The “SC” in the diagram is a .05 uf capacitor. (.047uf will work just as fine if it’s what you have!)
All put back together and ready to rock with 5 more pickup combinations!
S-1 Switch Up (off):
Position 1. Bridge Pickup
Position 2. Bridge and Middle Pickup in Parallel
Position 3. Middle Pickup
Position 4. Middle and Neck Pickup in Parallel
Position 5. Neck Pickup
S-1 Switch Down:
Position 1. Bridge Pickup in Series with Middle Pickup
Position 2. Bridge Pickup in Parallel with Special Capacitor and in Series with Middle Pickup
Position 3. Bridge/Middle/Neck Pickups with Neck and Bridge Pickups in Parallel and in Series with Middle pickup
Position 4. Neck Pickup in Parallel with Special Capacitor and in Series with Middle Pickup
Position 5. Neck Pickup in Series with Middle Pickup
I have been so busy with repairs I have not taken any pictures recently, but Tonight’s project was an EHX v256 vocoder. Came in with a broken tone pot and subminiature mic gain switch. Had to pull the whole PCB in order to access those parts.
A bit of time on the bench and it’s ready for another thousand Gigs!
Can you guess what control was replaced? That nice shiny knob looks a little bit out of place.. But by the looks of things, it will be right at home before long! 🙂
Today on the bench, a Yamaha Stagepas 300 with very noisy fans. Over time, dust will build up inside the unit and bind up the fan bearing causing a grinding and whirring noise.
I chose a sleeve bearing, low noise computer fan set for this application. I did have splice the old connector on to the new fan since Yamaha used a smaller connector than standard.
There are two fans. 50mm and 40mm
The 50mm one is sitting out in the open, two screws and its out! Replacing this one is simple.
The 40mm one is buried and required all of the lower board screws to be removed and pulled from the casing.
I also needed to countersink the fan mounting holes in order to mount the fan correctly.
Reassemble and test. Nice and quiet! No fan noise.