Tractor Beam - all buttoned up.

[mark123]

I finally got the Neutrik jacks I needed in the mail today and got the Tractor Beam all buttoned up.  I noticed that when the effect is engaged that I get a rather significant volume drop.  The phasing works as it should and it has TONS of adjustment and versatility.  I really like it.  The 20k LEVEL trim pot is dimed and it still has the volume drop.

Any tips?

[madbean]

First thing I would look at it making sure you have used 1.43k (or closest value to it) where it says and that your trimmer is actually 20k (not 2k, etc). The output section is really simple so either the resistors going in or the trimmer are to blame for too low a signal.

[mark123]

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OPA2134 DC      LM358 DC      TLE2074 DC     
1 *mV              1 varies           1 *mV             
2 *mV              2 varies           2 *mV             
3 *mV              3 varies           3 *mV             
4 -8.38v           4 -8.38v           4 9.05v
5 *mV              5 varies           5 *mV
6 *mV              6 varies           6 *mV
7 *mV              7 varies           7 *mV
8 9.05v            8 9.05v            8 *mV
                                       9 *mV
                                       10 *mV
                                       11 -8.38v
                                       12 *mV
                                       13 *mV
                                       14 *mV

[mark123]

First thing I would look at it making sure you have used 1.43k (or closest value to it) where it says and that your trimmer is actually 20k (not 2k, etc). The output section is really simple so either the resistors going in or the trimmer are to blame for too low a signal.

Hmmm.  Everything looks to be correct.  I'm going to try a 200k trimmer if I can get it back apart.  I tried the 200k trim pot and dimed it almost gets to unity. Hmmm.

[mark123]

The 1.43k ohm resistors are marked 1.4k on the silkscreen, correct?  I'm just going to replace them. 

[mark123]

I think the odd-ball 1.43k resistors were bad.  Two of them disintegrated after I unsoldered them.  It still works with the 200k LEVEL trim pot so I'll keep it. 

This is one phaser that sounds much better in the effects loop.  Usually, I prefer them before the amp.

Messing with this one also made me think to adjust my MXR Phase 95.  Previously, I wasn't happy with it because it pulsed instead of swept evenly.  I adjusted the trim pot and it sounds much better.

Regardless, I love the versatility of the Tractor Beam and I'll probably integrate it into my pedalboard.

[madbean]

The 1k43 are not critical. They could just as easily by 1k5. Or 1k4. Using a 200k trim is okay so long as you keep the overall volume level under control. Turn it up too much and it will distort a lot. But, a 200k might make it harder to find the sweet spot since the range it works correctly over is reduced by a factor of 10. Anyway as long as you have it working properly then that's what counts.

[mark123]

The trim pot is handy because if you adjust it for the effects loop it's way, way, way too low before the amp and vice versa.  Makes me think I've still got something wrong.

[mark123]

I'm going to go over it piece by piece and make sure I didn't make a mistake with component values and I'm also going to bypass the switching and just go into and out of the audio board.

[mark123]

UGH! When I replaced the 1k 1/8w resistor with the suggested 1/2w I put the 1k resistor in place of the 10M resistor. So that makes the input impedance of the effect 1k.    It sure was dark and quiet. 

Let me say, it's a real (B-WORD) taking out those Neutrik jacks.    Now turning up the 200k trimpot really does distort really nicely. LOL.  Can I order a new switch board by itself?