Schematic for POD XT

[tarahall 1]

Although I now have a POD HD500, I still really like my POD XTs (I have 2 of them). I would like to patch in an FX Loop or AUX Send & Return into my POD XT taking the signal out after the guitar input and feed it back in just before the output so it bypasses any of the DSP effects.

 

Has anyone done this and/or are there any schematics for the POD XT anywhere?

[Tinyfireball 0]

My email vdodge@mail.ru send me letter , I will reply with the diagram podXt

[tarahall 1]

My email vdodge@mail.ru send me letter , I will reply with the diagram podXt

If you have a schematic you can send it to my email address: :tarahall1950@gmail.com"

thanks

[tarahall 1]

My email vdodge@mail.ru send me letter , I will reply with the diagram podXt

 

I received your email so thank you very much for your help.

 

There was this topic question on this forum:

 

http://line6.com/support/topic/10543-pod-20-auxiliary-input-mod/

 

The reply by Miroslav was very useful but resistors R92 & R94 in his answer are for the POD 2.0.

Without the schematic for this model I cannot be sure just where he is patching into the headphone out.

 

Do you possibly have the section of the diagram for the POD 2.0 showing this modification or can you tell me which resistors would be the relative ones in the XT model?

[MiroslavKloud 15]

Hi, this schematic I have not longer available. I did a "reverse engineering" and I sketched on paper the schematic of amplifier for the headphone output. But I threw away it. If you have the schematic for XT, send it to me, maybe I can help you.

[tarahall 1]

Hi, this schematic I have not longer available. I did a "reverse engineering" and I sketched on paper the schematic of amplifier for the headphone output. But I threw away it. If you have the schematic for XT, send it to me, maybe I can help you.

 

Thanks Miroslav, It is on it's way

[tarahall 1]

Hi, this schematic I have not longer available. I did a "reverse engineering" and I sketched on paper the schematic of amplifier for the headphone output. But I threw away it. If you have the schematic for XT, send it to me, maybe I can help you.

 

I would like to patch in an FX Loop or AUX Send & Return into my POD XT taking the signal out after the guitar input and feed it back in just before the output so it bypasses any of the DSP effects.

 

So far I have these 2 circuit ideas with a small PCB already basically designed. However I'm not 100% sure where to patch them in.

 

[BillBee 393]

Would the Boss LS-2 be of any help in this?

[tarahall 1]

Would the Boss LS-2 be of any help in this?

 

Hi Bill,

 

I had already tried that type of approach but the basic idea is/was to have the aux send/return as a main integral part of the POD's built in circuitry rather than try and achieve the result using an external device to mix the two separate signal lines.

 

cheers

[BillBee 393]

Gotcha! Hope you succeed!!

[MiroslavKloud 15]

I opened my POD 2.0 again - the circuit is identical with the XT, only here are used a different values of resistors and it does not matter.
R92 in POD 2.0 = R110 in XT (also R107 and pin 2 on U28-A)
R94 in POD 2.0 = R109 in XT (R104 and pin 2 on U27-A)

 

I recommend the input resistors 20 kohm for gain = 1
Higher value of the resistors = lower gain.

 

Beware of mixing the signal from the XT and from the external effects - here can be a problem with phase shift.

[tarahall 1]

I opened my POD 2.0 again - the circuit is identical with the XT, only here are used a different values of resistors and it does not matter.

R92 in POD 2.0 = R110 in XT (also R107 and pin 2 on U28-A)

R94 in POD 2.0 = R109 in XT (R104 and pin 2 on U27-A)

 

I recommend the input resistors 20 kohm for gain = 1

Higher value of the resistors = lower gain.

 

Beware of mixing the signal from the XT and from the external effects - here can be a problem with phase shift.

 

Thanks for clarifying the resistors. I thought that was probably where you had patched the H/P in but I wanted to be sure.

 

I had thought of taking the effect send off the junction of R20, R25 and Pin1 of the OPA2134 which seems to be the logical point of patching headphones in.

 

I know that phase shift may be a problem but I will only find that out by trial and error so I'll see when I get to that stage.

 

I was thinking of feeding the returns back in at pins 3 & 6 of the master volume.

 

I have 2 of these units so I was only going to modify one of them.

 

cheers.

[MiroslavKloud 15]

I have a problem I do not understand exactly how you want to use exactly this. I'm not good in English.

I had thought of taking the effect send off the junction of R20, R25 and Pin1 of the OPA2134 which seems to be the logical point of patching headphones in.

 

If you want to use the signal from the junction of R20 and R25 and bring this signal to the input of external guitar effect - here is the signal 3x stronger than on the guitar input. It may cause unwanted overdriving.

I was thinking of feeding the returns back in at pins 3 & 6 of the master volume.

 

It is not good do feeding an external signal directly to the output of the operational amplifier (U18).

If you want use the MASTER VOLUME also for external audio, I recommend to interrupt the connection between pin 1 (U18-A) and pin 3 of the master volume and inserted here a resistor - for example 1k and the external signal connect also through 1k resistor. And the same for the second channel. This causes a slight decrease in overall volume, but it will work.

[tarahall 1]

I have a problem I do not understand exactly how you want to use exactly this. I'm not good in English.

If you want to use the signal from the junction of R20 and R25 and bring this signal to the input of external guitar effect - here is the signal 3x stronger than on the guitar input. It may cause unwanted overdriving.

 

Is it better to take signal from Input Jack and use IC buffer ? ... I try to describe better with circuit diagram #1 - AuxSend-2.jpg:

 

 

 

It is not good do feeding an external signal directly to the output of the operational amplifier (U18).

 

"If you want use the MASTER VOLUME also for external audio, I recommend to interrupt the connection between pin 1 (U18-A) and pin 3 of the master volume and inserted here a resistor - for example 1k and the external signal connect also through 1k resistor. And the same for the second channel. This causes a slight decrease in overall volume, but it will work."

 

 

Perhaps circuit diagram #2 - AuxReturn-2.jpg  explain idea better:

 

[MiroslavKloud 15]

Yes. But I would not use C1 and R1 - R1 would have been parallel to the R16 in XT.
To the second circuit diagram I will return tomorrow.

 

Edit: I mistakenly wrote R16, R15 is correctly.

[MiroslavKloud 15]

My proposal

[tarahall 1]

Yes. But I would not use C1 and R1 - R1 would have been parallel to the R16 in XT.

To the second circuit diagram I will return tomorrow.

So leave R1 out. Do I still use C1?

[tarahall 1]

My proposal

 

So no need a capacitor between pin1 (or 7) and the 1k resistor in the return circuit?

[MiroslavKloud 15]

So leave R1 out. Do I still use C1?

 

Not. The input of the operational amplifier must be grounded. If you leave R1 and C1 out, R15 in XT ensures grounding. Input impedance is not changed by adding a second operational amplifier. If you use the R1 and C1, the input impedance will be 500K. This may not be harmful, but I see no reason to do this.

So no need a capacitor between pin1 (or 7) and the 1k resistor in the return circuit?

 

According to me it is not necessary, at the outputs of both operational amplifiers is zero DC voltage. The capacitor can be used, if so, should have at least 2.2 microfarads.

But certainly it is necessary resistor between pin 1/7 (U18), and 3/6 (master volume).

[tarahall 1]

Not. The input of the operational amplifier must be grounded. If you leave R1 and C1 out, R15 in XT ensures grounding. Input impedance is not changed by adding a second operational amplifier. If you use the R1 and C1, the input impedance will be 500K. This may not be harmful, but I see no reason to do this.

According to me it is not necessary, at the outputs of both operational amplifiers is zero DC voltage. The capacitor can be used, if so, should have at least 2.2 microfarads.

But certainly it is necessary resistor between pin 1/7 (U18), and 3/6 (master volume).

 

Thank you very much for your help. I have design PCB to fit in shell of XT near output control

[tarahall 1]

But certainly it is necessary resistor between pin 1/7 (U18), and 3/6 (master volume).

 Hi Miroslav,

 

Pleased to tell you that putting 1k resistors between pin 1/7 (U18), and 3/6 (master volume) has little change in volume.

[tarahall 1]

I opened my POD 2.0 again - the circuit is identical with the XT, only here are used a different values of resistors and it does not matter.

R92 in POD 2.0 = R110 in XT (also R107 and pin 2 on U28-A)

R94 in POD 2.0 = R109 in XT (R104 and pin 2 on U27-A)

 

I recommend the input resistors 20 kohm for gain = 1

Higher value of the resistors = lower gain.

 

All good so far.

 

This simple mod works great with either my IPOD, BOSS MicroBr or Galaxy Tab3.

 

 

Gavan.

[tarahall 1]

Thank you very much for your help. I have design PCB to fit in shell of XT near output control

 

I finally got one of these boards made and installed after a couple of revisions. The input section of the send is jumperable for phase reversal, and the pot controls the input level in the return section.

 

If ypu want to match the sounds of your old delay, chorus or other stomp box pedals to the units in the POD, this mod allows you do so with comparative ease. It also works a treat for playing along with an external band track from an IPOD, DAW or similar. Even a looper with a separate effects setup is another possibility.

 

Many thanks to Miroslav for his advice and assistance.

[MiroslavKloud 15]

Good work!  :)