Anyone know how to make a Ceriatone Centura true bypass?

[psychodave]

I really like the Centura, but I’d like to make it true bypass since I don’t always like the buffered signal.

Here is the layout. Thx.

http://www.ceriatone.com/ceriatone/wp-c ... 17-Doc.pdf

 

[scottosan]

I really like the Centura, but I’d like to make it true bypass since I don’t always like the buffered signal.

Here is the layout. Thx.

http://www.ceriatone.com/ceriatone/wp-c ... 17-Doc.pdf

Consdier making a looper pedal to bypass it? It'd be easier that bastardizing the pedal since the input never sees the dpdt switch. A DIY looper would cost under $20

 

[psychodave]

I really like the Centura, but I’d like to make it true bypass since I don’t always like the buffered signal.

Here is the layout. Thx.

http://www.ceriatone.com/ceriatone/wp-c ... 17-Doc.pdf

Consdier making a looper pedal to bypass it? It'd be easier that bastardizing the pedal since the input never sees the dpdt switch. A DIY looper would cost under $20

I figured it was something goofy. I did extensive searches and couldn’t find how to do it. I guess I’ll leave it alone. I find the buffer to add some high end that I don’t like.

Thx for responding.

 

[scottosan]

I really like the Centura, but I’d like to make it true bypass since I don’t always like the buffered signal.

Here is the layout. Thx.

http://www.ceriatone.com/ceriatone/wp-c ... 17-Doc.pdf

Consdier making a looper pedal to bypass it? It'd be easier that bastardizing the pedal since the input never sees the dpdt switch. A DIY looper would cost under $20

I figured it was something goofy. I did extensive searches and couldn’t find how to do it. I guess I’ll leave it alone. I find the buffer to add some high end that I don’t like.

Thx for responding.

i run a couple Klones stacked as well as a TS-808 and a JHS AT clone. No need for multiple buffers so I made 5 loop looper

 

[glpg80]

It doesn't help the schematic doesn't match the layout.

Regardless, I think I reverse engineered it assuming they use a DPDT. It's quite cunning actually. They take what looks to be a negative feedback circuit but is actually a bypass forward path when the pedal is "off" which is still technically in circuit due to the first buffer.

Here's a fix you can try - unsolder W3, but leave it connected to the DPDT. Solder the open end of that wire to the tip/hot of the input jack which also goes to W2. The W3 hole should be open. See if that does what you want for true bypass.

There shouldn't be a volume drop associated with when the pedal is off and on. If there is a volume imbalance doing this, then shoot me a PM. I have something else to recommend which is similar but uses a bit of their own passive circuitry to balance the off/on states.

And fuck Ceriatone for their error-prone mesa style schematics. This is 2018 not 1978. They literally have the single-sided board design captured in the same document.

 

[R Weaver FX]

I've been plugging into Friedman's buffer in the Buffer Bay after my dirt pedals(including the Centura) and then out to my modulation and time based pedals and it works like a charm. I'm getting the best tone from a pedalboard I've ever gotten and my base amp tone is fully intact.

 

[scottosan]

It doesn't help the schematic doesn't match the layout.

Regardless, I think I reverse engineered it assuming they use a DPDT. It's quite cunning actually. They take what looks to be a negative feedback circuit but is actually a bypass forward path when the pedal is "off" which is still technically in circuit due to the first buffer.

Here's a fix you can try - unsolder W3, but leave it connected to the DPDT. Solder the open end of that wire to the tip/hot of the input jack which also goes to W2. The W3 hole should be open. See if that does what you want for true bypass.

There shouldn't be a volume drop associated with when the pedal is off and on. If there is a volume imbalance doing this, then shoot me a PM. I have something else to recommend which is similar but uses a bit of their own passive circuitry to balance the off/on states.

And fuck Ceriatone for their error-prone mesa style schematics. This is 2018 not 1978. They literally have the single-sided board design captured in the same document.

As for the schematics and single sided board, they are accurate and true to the original Klon from what I can tell. A little blurry in the document, but in typical Ceriatone style they don't ever design anything just copy it. The market here is for people who want a Klon replica.

As for the recommended mod, your signal will be heavily loaded down. Not ony is the R28 - 100K resistor to ground that is still in circuit, but also a maximum of 78K (R27 - 68k & volume 10k) paralleling that to ground (depending on volume setting). Your signal will we seeing no more than 44k to ground and loose alot of volume and high end. Also when the effect is on, you clean signal would still be in signal only attenuated by a 68 resistor. The foot switch only shorts out either of the 68K resistor is really more there to prevent popping on one side and shunts either the LED of the effect signal to ground with the other half.

These pedal are going for $300 or so, and there are alot of cheap copies out there that are true bypass. I'd leave it alone, get a looper, or pick up a cheap knock off like the Caline that is true bypass.

 

[glpg80]

It doesn't help the schematic doesn't match the layout.

Regardless, I think I reverse engineered it assuming they use a DPDT. It's quite cunning actually. They take what looks to be a negative feedback circuit but is actually a bypass forward path when the pedal is "off" which is still technically in circuit due to the first buffer.

Here's a fix you can try - unsolder W3, but leave it connected to the DPDT. Solder the open end of that wire to the tip/hot of the input jack which also goes to W2. The W3 hole should be open. See if that does what you want for true bypass.

There shouldn't be a volume drop associated with when the pedal is off and on. If there is a volume imbalance doing this, then shoot me a PM. I have something else to recommend which is similar but uses a bit of their own passive circuitry to balance the off/on states.

And fuck Ceriatone for their error-prone mesa style schematics. This is 2018 not 1978. They literally have the single-sided board design captured in the same document.

As for the schematics and single sided board, they are accurate and true to the original Klon from what I can tell. A little blurry in the document, but in typical Ceriatone style they don't ever design anything just copy it. The market here is for people who want a Klon replica.

As for the recommended mod, your signal will be heavily loaded down. Not ony is the R28 - 100K resistor to ground that is still in circuit, but also a maximum of 78K (R27 - 68k & volume 10k) paralleling that to ground (depending on volume setting). Your signal will we seeing no more than 44k to ground and loose alot of volume and high end. Also when the effect is on, you clean signal would still be in signal only attenuated by a 68 resistor. The foot switch only shorts out either of the 68K resistor is really more there to prevent popping on one side and shunts either the LED of the effect signal to ground with the other half.

These pedal are going for $300 or so, and there are alot of cheap copies out there that are true bypass. I'd leave it alone, get a looper, or pick up a cheap knock-off like the Caline that is true bypass.

No, my signal is not loaded down. R28 or R27 or any of that garbage does not matter with my modification because W3 is no longer in the circuit. I'm using the DPDT to bypass ALL of the forward path when the pedal is in the off position. Go back and look at the masking layer of the board, not the schematic, and look at how the switch is connected. Re-read my modification once again, and then think about it

 

[scottosan]

It doesn't help the schematic doesn't match the layout.

Regardless, I think I reverse engineered it assuming they use a DPDT. It's quite cunning actually. They take what looks to be a negative feedback circuit but is actually a bypass forward path when the pedal is "off" which is still technically in circuit due to the first buffer.

Here's a fix you can try - unsolder W3, but leave it connected to the DPDT. Solder the open end of that wire to the tip/hot of the input jack which also goes to W2. The W3 hole should be open. See if that does what you want for true bypass.

There shouldn't be a volume drop associated with when the pedal is off and on. If there is a volume imbalance doing this, then shoot me a PM. I have something else to recommend which is similar but uses a bit of their own passive circuitry to balance the off/on states.

And fuck Ceriatone for their error-prone mesa style schematics. This is 2018 not 1978. They literally have the single-sided board design captured in the same document.

As for the schematics and single sided board, they are accurate and true to the original Klon from what I can tell. A little blurry in the document, but in typical Ceriatone style they don't ever design anything just copy it. The market here is for people who want a Klon replica.

As for the recommended mod, your signal will be heavily loaded down. Not ony is the R28 - 100K resistor to ground that is still in circuit, but also a maximum of 78K (R27 - 68k & volume 10k) paralleling that to ground (depending on volume setting). Your signal will we seeing no more than 44k to ground and loose alot of volume and high end. Also when the effect is on, you clean signal would still be in signal only attenuated by a 68 resistor. The foot switch only shorts out either of the 68K resistor is really more there to prevent popping on one side and shunts either the LED of the effect signal to ground with the other half.

These pedal are going for $300 or so, and there are alot of cheap copies out there that are true bypass. I'd leave it alone, get a looper, or pick up a cheap knock-off like the Caline that is true bypass.

No, my signal is not loaded down. R28 or R27 or any of that garbage does not matter with my modification because W3 is no longer in the circuit. I'm using the DPDT to bypass ALL of the forward path when the pedal is in the off position. Go back and look at the masking layer of the board, not the schematic, and look at how the switch is connected. Re-read my modification once again, and then think about it

Are you actually using this circuit? I have have build a dozen of these and have 4 right now. If am reading your suggestion correctly, you are removing W3 from the dpdt and connecting the input to the lug of the DPDT that W3 currently occupies. If that is the case it's loaded down. I just verified it. W11/W12 are the output. Sorry if I am misunderstanding you. On that side of the DPDT, you are only 1 of the 68K resistors.

 

[glpg80]

No, I don't own the pedal and haven't seen the circuit before. I've been working from home and finally had a chance to sit down and look at it further.

Long story short, it can be converted to true bypass, while also fixing a few of the pedal shortcomings, but it's more involved than a simple wire swap by far.

The muting circuit they're doing by grounding W7 causes a problem with the next coupling cap creating a capacitive discharge which is amplified through the chain to the output when the pedal is switched to the on position. There's also popping on the switch for a few other reasons like DC offset existing on the output of the last op-amp. The resistor network is there to load the output impedance and limit the DC offset out of the last opamp before it leaves to the DPDT and then to the output jack. That's why there are two versions of the circuit from ceriatone to try to mitigate these problems.

Here's a scanned pdf of the mods you would need to complete to remove the volume jump when going to true bypass, attempt to remove the DC offset to account for the true bypass modification, and make it true bypass in the first place.



If this doesn't work, there's nothing else you could do due to space limitations and making things more complicated than they need to be or due to the inherent limitations of the design itself.