Issue With New HB II Piezo

[Eric Yoon]

Hi guys, I picked up a Hollowbody II Piezo a week ago and noticed the electronics are acting strange.

When plugged into both the Mix and Piezo and switched to the Piezo-only mode, the master volume knob increases the volume until reaching 9, then drops from 9 to 10. The blend knob increases the volume just fine. This doesn't happen when its plugged into the mix only ( only a single cable into the guitar ), the master volume knob increases the volume until reaching its max at 10 but the piezo blend knob doesn't affect the volume at all.

Now in the Piezo & Electric mode ( switch in the middle position ) with both cables in, the master volume knob doesn't change the volume much, if at all, from 0 to 9, then suddenly the volume increases a lot from 9 to 10. This is different when using a single cable into the mix port, the master volume knob increases the volume evenly all the way to 10.

The dealer I purchased this HB II Piezo from doesn't have anymore in stock to compare the electronics to when I asked. I was given the choice to either send it to their tech center, or they would cover up to $80 for repair if choose someone local. I've since talked to PTC and was told to send an email with the issues mentioned for them to investigate further.

Just wondering if any HB II Piezo owners could confirm if mine is not supposed to act this way. This is my first PRS and first expensive electric ( Heard PRS had great QC on their guitars, especially the core 10 tops like mine, so its frustrating that I may need to send it for repair already ).

 

[shimmilou]

PEBKAC?

https://www.prsguitars.com/documents/PRS_LR_Baggs_Piezo_Operating_Instructions.pdf

 

[shinksma]

Is this an SE or Core HB II Piezo? You say "Core 10 tops like mine" so I assume Core, but I hate assuming things...

 

[Eric Yoon]

Is this an SE or Core HB II Piezo? You say "Core 10 tops like mine" so I assume Core, but I hate assuming things...

Its a core model

 

[shinksma]

When plugged into both the Mix and Piezo and switched to the Piezo-only mode, the master volume knob increases the volume until reaching 9, then drops from 9 to 10. The blend knob increases the volume just fine. This doesn't happen when its plugged into the mix only ( only a single cable into the guitar ), the master volume knob increases the volume until reaching its max at 10 but the piezo blend knob doesn't affect the volume at all.

Now in the Piezo & Electric mode ( switch in the middle position ) with both cables in, the master volume knob doesn't change the volume much, if at all, from 0 to 9, then suddenly the volume increases a lot from 9 to 10. This is different when using a single cable into the mix port, the master volume knob increases the volume evenly all the way to 10.

OK, So now that I have experimented with one of mine, I can say the following:

Your operation with just one plug into the mix/mag jack sounds correct. Note, the Blend knob will affect how much mag vs piezo is in the mix when the mini-toggle is in the middle position. Note 2: you should be able to tell if the circuit is behaving 100% correct with only one cable plugged in by playing with the mag pickup selector (big toggle) and tone knob - those affect only the mag pickups, so you should hear them change the tone if mini-toggle in mag-only, and have no effect if in piezo-only.

The issue you have is with two cables plugged in:

If you have cables plugged into both mix/mag and piezo jacks, and the mini-toggle is in piezo mode, you should get zero signal out of the mix/mag jack, regardless of the "Master volume" position. The "blend" knob becomes the Piezo volume knob, and will affect the piezo signal only, going out the piezo jack.

With the mini-switch in the middle position, both volume knobs are active, affecting their part of the signal going out of their respective jacks.

i.e., if you have two plugs into the two jacks, the guitar has two signals now operating independently: the mag pups controlled by the "Master Volume" to the Mag/mix jack, and the piezo controlled via the "Blend" knob (now Piezo volume) going to the PIezo jack. The mini-toggle controls which output(s) is/are active - mag, both, or piezo.

What you are experiencing sounds like a mis-wired "master volume" pot or something not quite right in the mixing circuit board.

 

[Eric Yoon]

OK, So now that I have experimented with one of mine, I can say the following:

Your operation with just one plug into the mix/mag jack sounds correct. Note, the Blend knob will affect how much mag vs piezo is in the mix when the mini-toggle is in the middle position. Note 2: you should be able to tell if the circuit is behaving 100% correct with only one cable plugged in by playing with the mag pickup selector (big toggle) and tone knob - those affect only the mag pickups, so you should hear them change the tone if mini-toggle in mag-only, and have no effect if in piezo-only.

The issue you have is with two cables plugged in:

If you have cables plugged into both mix/mag and piezo jacks, and the mini-toggle is in piezo mode, you should get zero signal out of the mix/mag jack, regardless of the "Master volume" position. The "blend" knob becomes the Piezo volume knob, and will affect the piezo signal only, going out the piezo jack.

With the mini-switch in the middle position, both volume knobs are active, affecting their part of the signal going out of their respective jacks.

i.e., if you have two plugs into the two jacks, the guitar has two signals now operating independently: the mag pups controlled by the "Master Volume" to the Mag/mix jack, and the piezo controlled via the "Blend" knob (now Piezo volume) going to the PIezo jack. The mini-toggle controls which output(s) is/are active - mag, both, or piezo.

What you are experiencing sounds like a mis-wired "master volume" pot or something not quite right in the mixing circuit board.

Thank you so much for this. Got everything figured out now and in the end, it seems that the issue was not coming from the guitar but from my signal chain. Never knew that could affect the controls on the guitar.

 

[shinksma]

Thank you so much for this. Got everything figured out now and in the end, it seems that the issue was not coming from the guitar but from my signal chain. Never knew that could affect the controls on the guitar.

Oh, wow. So you had some sort of signal combiner between the guitar and amp, taking in the signals from the two plugs? Yeah, I guess that could cause issues. Feel free to explain, to help anyone else looking to do something similar.

 

[Single_tone]

What was the purpose of using a signal combiner?

 

[shinksma]

What was the purpose of using a signal combiner?

I was just guessing it might be something like that. Need the OP to chime in and explain, if possible.

 

[Eric Yoon]

Oh, wow. So you had some sort of signal combiner between the guitar and amp, taking in the signals from the two plugs? Yeah, I guess that could cause issues. Feel free to explain, to help anyone else looking to do something similar.

So my pedalboard starts with the Whirlwind Selector Active A/B Switch Box and I plugged in both the Mix/Mag & Piezo cables into it. The selector is able to go from two guitar inputs into one amp, or one guitar into two amps so I figured it would be fine for the HBII Piezo. The idea was to easily switch between the Mag or Piezo pick ups while being able to use my pedalboard.
When both plugged in and both channels are turned on the selector, the strange control issues are present ( theoretically, there shouldn't be any issue.. but thats not the case ).

I've since removed the Piezo cable from the pedalboard and plugged it into my DI, so only the Mix/Mag cable is going through the pedalboard. Basically as if I had the Mix/Mag going into a standard amp and the Piezo going into an Acoustic amp / preamp as the HBII Piezo is most commonly configured in. This doesn't have the issues mentioned above.

I'm not sure if the selector just isn't capable of handling this configuration, so I'll be trying to get a replacement for it to see if the issue continues, but for now, I'm just happy to find out that the guitar is acting as should when routed in a more traditional way.