EHX - Pitch Fork

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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LaceSensor
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Post by LaceSensor »

Hi,

Just got one of these in. For the money it is excellent. Separate clean blend would have been useful for both up and down, but otherwise it does a lot for the size and cash.
Put it in a TBP loop and the buffer is excellent also, very transparent.
Nice to see EHX using better hardware these days too - SCI footswitch, Neutrik metal jacks.
One oddment, the potentiometer looks like a normal 16mm B100k, but it has indents to separate out the mode selections on the pitch dial.

Anyway, here are the guts.

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Sweetalk
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Post by Sweetalk »

Can you read the AD part number?

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Govmnt_Lacky
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Post by Govmnt_Lacky »

Sweetalk wrote:Can you read the AD part number?
Unless you have the proprietary coding for the chip.... what good would it do? Mods??

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Sweetalk
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Post by Sweetalk »

Govmnt_Lacky wrote:
Sweetalk wrote:Can you read the AD part number?
Unless you have the proprietary coding for the chip.... what good would it do? Mods??
Justo for some research, I'm going to merge to AD DSP's

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Govmnt_Lacky
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Post by Govmnt_Lacky »

@Lacesensor

On the pot side of the PCB... under the Blend pot...

Is that some kind of metal heatsink for the DSP chip?

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LaceSensor
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Post by LaceSensor »

Govmnt_Lacky wrote:@Lacesensor

On the pot side of the PCB... under the Blend pot...

Is that some kind of metal heatsink for the DSP chip?

Not sure. It's not particularly raised up. It's in the right place though, so possibly.


Regards the CPU part number I'll check tomorrow

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LaceSensor
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Post by LaceSensor »

Sweetalk wrote:Can you read the AD part number?
BF592KCPZ
2890357.1
Black Fin

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LaceSensor
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Sweetalk
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Post by Sweetalk »

Thanks LaceSensor!, it's a little bit smaller than the DSP used in the larger EHX pedals (BF531 Blakfin series as well). Thanks!.

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B3ar
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Post by B3ar »

You can get 11-detent Alphas from Small Bear and Mouser. Which is relevant to my question:

Anyone verified a preset switching scheme mod for the Pitch Fork yet like for the Micro Pog? Word is that T1M is already offering that one, so it's definitely doable. I could probably guess from the Tagboard Effects Micro Pog mod layout, but I'm timid to lead on digital devices.

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Whoismarykelly
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Post by Whoismarykelly »

I currently use a Micro POG to simulate bass in one of my rigs. I have a Pitch Fork in the mail to replace the POG because it has a pure octave down while the Micro POG always has a tiny bit of dry and octave up bleed which lends an unwanted synthy quality. However, the Pitch Fork doesn't have the dry out that the POG has. Looks like it has room in the battery cavity to add a jack though and it may be possible to tap the buffered dry signal off one side of the blend pot. Anyone with one of these on hand able to verify that the blend is a simple matter of dry on one node and wet on the other with the wiper feeding the output?

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geoffw
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Post by geoffw »

Anyone got further with this? I'd like to either add a dry out, or interrupt the effects pre-blend and do a send receive for an effects loop.

any thoughts? Anyone tried either?

Cheers, geoff

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Post by jbenward »

Geoff-

I don't have this pedal, but looking at the pics it looks like U2 or U9 might be an op amp acting as a buffer to blend the output from the DSP with the dry signal. I can't see the writing on the chips, but from the footprint I would assume they are op amps. If you have an audio probe or scope I would start with getting the dottiest and probing those chips output.

-Ben

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Post by harmonica_player »

Just get EHX Pitch Fork, and I really like its tone and fast response and a lot of possibilities. I also want to use it like whammy with expression pedal, but instead of pedal I get expression knob http://jkmods.ru/collection/frontpage/p ... sionsingle. It have stereo output, 10k linear pot. I already found that I need cable with tip and ring connected reverse and I made such a cable, but I got another problem. All way down it gives 10kOhm, all way up it gives zero resistance between tip and ring. Unfortunately turning knob gives me full range from all way down to just around a bit more than half way up (this position gives tip-ring resistance about 4kOhm) and turning knob up don't change anything more. I'd prefer to get a full range for a complete turn. What solution will you recommend? Do you recommend to get a audio/logarithmic taper pot or to try another resistance?

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muki
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Post by muki »

Govmnt_Lacky wrote:@Lacesensor

On the pot side of the PCB... under the Blend pot...

Is that some kind of metal heatsink for the DSP chip?
Ground fill is mainly used for better ground impedance, all the DSP's ground pins will be via'd directly to it. Such is the world of high-speed digital parts!

It can also be used as a heat-sink.They left the solder mask off so that wave soldering added extra thickness to the fill, creating a cheap heat sink.

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LesGerver
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Post by LesGerver »

Hi there,


I had a problem while using the Pitch Fork and the DD2 just burned down. Can you please respond with the component model as I will need to replace it.


Thanks!!

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LesGerver
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Post by LesGerver »

LesGerver wrote:Hi there,


I had a problem while using the Pitch Fork and the D2 just burned down. Can you please respond with the component model as I will need to replace it.


Thanks!!

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thereminator
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Post by thereminator »

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EHX - Pitch Fork guts
EHX - Pitch Fork guts
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In theory, there is no difference between theory and practice. But, in practice, there is.

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