Palmer PDI-09 Junction

What is it?

PDI-09 is a direct box/speaker simulator intended to be used with either line-level or speaker-level signal. In other words, it tries to recreate frequency response of a guitar speaker and allow us to plug the guitar/pedal/preamp/amp directly to a mixer or recorder. It’s very similar to the famous Palmer PDI-03 speaker sim, just without the dummy load (PDI-03 is used by some famous guitarist, like Joe Satriani). The lack of a dummy load isn’t necessarily a bad thing because: a) it costs a quarter of the price of PDI-03 and b) you can experiment with various dummy loads to find the one that you like the most – resistive, reactive, speaker motor, real speaker, etc.

Palmer PDI-09

Do I need it?
These are the typical use cases:

  • You have an amp but don’t want to play though the speaker for some reason (neighbors). Running the amp into a dummy load and tapping the signal to the speaker sim is a nice option.
  • You have an amp and a cab, but either don’t have a mic or don’t want to bother with mic-ing. Using a speaker sim will give consistent results for recording – it eliminates room effect, mic placement or mic type from the equation.
  • You have a preamp or a pedal and want to record it directly.
  • 3 EQ settings – normal, mellow, bright. I found that normal is the one that suits me the most. Bright is just too bright and mellow is too warm.
  • 3 attenuation levels – 0dB, 15dB, 30dB. Very useful in case you need to reduce the signal level. 0db should be used with preamps, 15dB with smaller amps and 30db with bigger amps.
  • Ground lift switch. With my setup having the ground switch off helped remove some ground loop noise, so kudos to it.
  • Input jack takes either line-level or speaker-level signal. When it’s connected to the amp output it needs the load to be connected to the “Thru” jack. Failing to do so will most likely kill the little Palmer but could also kill the amp itself.
  • Balanced output. I don’t have any device that works with balanced signal so I made a cable with XLR jack on one end and a standard 1/4″ jack on the other. Half of the signal is thrown away in the process but it usually doesn’t matter because I have to attenuate it anyways. If you need to keep most of the signal, using a transformer to couple the signal back to unbalanced or some sort of a buffer is probably the way to go.
Video Clips

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  • Sounds great
  • Build quality
  • Can work off of both line and speaker level (external load needed) signal
  • Passive design, no batteries needed
  • Bright/mellow settings could be a bit more subtle
  • A bit pricey, especially in the US

I love it. For the last couple of months it’s been a corner stone of my rig, either with amps or preamps. Build quality is very high – nice metal casing and recessed switches should guarantee long life. If you need a speaker sim, try Palmer, you won’t be disappointed. For the reference, most of the clips on my site are recorded using the Palmer.

Did you reverse engineer it?

Unfortunately, no. I opened it up the moment it arrived, but they cleverly molded the heart of the device so it can’t be traced without destroying it. Folks on SloClone forum reverse engineered PDI-03, but since both of them have some custom inductors and transformers, getting the real thing is much easier.

4 Responses to “Palmer PDI-09 Junction”
  1. gorthkill666 says:

    Can I connect a multieffect pedal to the PDI 03. I want use the amp head emulation that it has, and after that, connect it to the palmer PDI-03 because I do not like the cabinet simulation of my pedal. Thanks!

    • Bancika says:

      It depends if you can disable onboard cab simulation on that pedal. If yes, then just plug it into PDI input. That’s how I used it most of the time.

  2. Danny says:

    Hi, Do you have the possibility of test the palmer with the little gem amp? (or similar lm386 amps). Thanks

    • Bancika says:

      I took the 386 out a couple of years ago for another project, so my little gem is not functional. I’ll try to buy another one when I go to the store.

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    The idea behind this site is to share my experience with Do It Yourself approach to guitars, amplifiers and pedals. Whether you want to save a couple of bucks by performing a mod or upgrade yourself instead of paying a tech, or want to build your own piece of gear from scratch, I'm sure you will find something interesting here. Also, this is the home of DIY Layout Creator, a free piece of software for drawing circuit layouts and schematics, written with DIY enthusiasts in mind.