downtown fuzz/ehx octave multiplexer : adding a volume boost ?

[eh la bas ma]

Hello,

I am trying to use this octaver in a song :

https://lectric-fx.com/wp-content/uploads/2019/09/Downtown.pdf

I'd like to start playing the guitar quietly, using an other overdrive, and then push the gain up suddenly thanks to the suboctave + fuzz, with the od still on. The od is connected before the octaver.

Problem is I have a volume drop when I engage the octaver. I have to either use an other boost pedal or stop playing to turn the od volume up. No volume control on the octaver... Using a boost pedal is trouble, i would have to activate both at the same time,  I'd like to keep it simple with my feet.

Should I try to fit a volume boost circuit inside the octaver, connected at the end of the signal path, or is there a simpler way to get more volume from this octaver ?

[Ell]

The easiest way I can think of is an AB loop box with in and out and send and return. So you have bypass be your clean signal, then when you hit the switch it will go out through send, into your octave and boost, back into return, and output to your amp. No need to mod your Octave

[eh la bas ma]

Thanks for your reply.

I 'll try to build a simple effect looper.




It looks really simple, I hope it'll work.

[duck_arse]

pardon, please, but I have a rant. this is the second translated circuit I've seen of late using an LM13700 in which a pair of "darlington transistors" have been added. you would think the IC people would have realised the need for buffering the OTA/VCA output when they updated the CA3080/whatever that other part number is, and added a darlington for each to the chip. it would be so much more versatile then.

rant ends.

[Scruffie]

pardon, please, but I have a rant. this is the second translated circuit I've seen of late using an LM13700 in which a pair of "darlington transistors" have been added. you would think the IC people would have realised the need for buffering the OTA/VCA output when they updated the CA3080/whatever that other part number is, and added a darlington for each to the chip. it would be so much more versatile then.

rant ends.

There is a darlington buffer in the chip, just no access to the collector like in the CA3094 (required for this kind of SVF, an op amp would work as well) and instead the anti-parallel diodes which have their own uses... but it would be nice if there was a chip option that did have it.

To increase gain to both wet & dry without adding an output boost I think the only real spot is at the input, so increasing R3 or decreasing R4.

[eh la bas ma]

So far, no signal through the looper.

I don't have any DC jack left, so I use a battery only :






I notice something strange : The led lights up when i plugg a jack IN, and it switches off when I plugg a jack OUT.

Something is wrong with the ground ?

Edit : the led resistor is on the negative side on the diagram, I connected it to the led positive side.

[eh la bas ma]

In case someone can spot something wrong...

[idy]

You have used a stereo jack to switch the battery off and on, I think on the input jack? When there is nothing plugged in, no light.
It may be that you have done things correctly, in which case using the stomp switch should turn the LED on and then off. No? You didn't say...

[eh la bas ma]

The led lights up when i use the 3pdt.

Now I have signal between In and Out, not in the fx loop though.

I tried a different 3pdt and another wiring, using a battery instead of a DC jack :

[eh la bas ma]

OK, the looper works, the dowtown fuzz doesn't... no wonder i had no signal in the fx loop...

It worked perfectly for 2 years, now the 3pdt makes a loud pop and the signal disappear when switched on.

I ll post all the usual readings if I can't sort this out quickly... 

[idy]

before you go poking around confirm that you fuzz has stopped working and that you have not merely reversed send and return. Confirm that send goes to in of fuzz, return to out. Easy way to confuse yourself!

[eh la bas ma]

Sub-octa-fuzz is fixed, thanks to Rob.

The easiest way I can think of is an AB loop box with in and out and send and return. So you have bypass be your clean signal, then when you hit the switch it will go out through send, into your octave and boost, back into return, and output to your amp. No need to mod your Octave

I just tried the effect loop and it's working very well, allowing to bring many effects together with one movement.

How could I live without this so far ?

Thank you very much for your suggestion, it will be put to good use.

[eh la bas ma]

To increase gain to both wet & dry without adding an output boost I think the only real spot is at the input, so increasing R3 or decreasing R4.

I will try a 100k trimmer, or even a pot, at R4, I notice I always set Blend control around 12 or more, and there's a volume loss unless Blend is CCW.

It could free me from using boosts, thanks !

[Ell]

Sub-octa-fuzz is fixed, thanks to Rob.

The easiest way I can think of is an AB loop box with in and out and send and return. So you have bypass be your clean signal, then when you hit the switch it will go out through send, into your octave and boost, back into return, and output to your amp. No need to mod your Octave

I just tried the effect loop and it's working very well, allowing to bring many effects together with one movement.

How could I live without this so far ?

Thank you very much for your suggestion, it will be put to good use.

Glad to hear it is working nicely! I've never actually done this myself. I might have to try it out based on YOUR recommendation haha! I hope it can help creativity and lead to cool song ideas for you eh la bas ma. I've been wanted to make a couple of Runoffgroove Tonemender EQ pedals. I might build a looper into one of them, so it could be used as just an EQ pedal, or you can use it as just a looper, or you can use it to play with the tone of your loop. Another project to join the queue haha.