Random Questions

[mminutel]

Alright. I am going to recase my pimeta and tread and possibly do a crossfeed. I am going to use Hammond aluminum cases with the metal ends. I already have the one picked out for my pimeta but the crossfeed I am not sure.

Anyways, anyone know the height for the standard crossfeed kit from tangent? It will be fine in a case with the aluminum ends correct? There isn't any power tied to it right?

What do you all use to label your cases apart from Front Panel Express. I do not want to have something extra to order and have seen some really nice work that doesn't look like it was done with FPE.

Are there any neat ways to hook up a tread to amp other than standard DC jacks? I have heard about the DIN but they have 3 pins so do you only use two of them? Also, anyone know of a quality male end and female panel mount? Will standard 26awg SPC do the job for the interconnect or do I need to go with something like 10awg? It shouldn't carry much current.

I will need a 4P3T switch for the crossfeed so can anyone recommend a good switch? Also, are there any nice looking knobs that will fit on the switch as well as my pimeta alps RK097 pot?

I would like to make the pimeta so that I can charge the batteries and then be able to turn the batteries off to keep them from overcharging. I am correct in assuming that this is accomplished by a simple SPST switch without a problem?

Does anyone have an LED on their pimeta that they particularly like. Mine is a standard radioshack which does the job but it is just hot glued into the hole and doesn't look that professional.

Can you make a pimeta have a switchable gain?

Sorry for all of the questions and there might be more but I want to be able to let this stuff sit on my desk and not have to do any more tweaking. Dang this place, the DIY bug has hit me a lot more than the headphone bug.

 

[tangent]

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Originally Posted by mminutel /img/forum/go_quote.gif anyone know the height for the standard crossfeed kit from tangent?

From the details page for that item on the shop page: "standoffs: 3/4" Keystone #4 aluminum spacers"

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It will be fine in a case with the aluminum ends correct? There isn't any power tied to it right?

Yes.

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Are there any neat ways to hook up a tread to amp other than standard DC jacks? I have heard about the DIN but they have 3 pins so do you only use two of them?

I wouldn't bother looking beyond regular barrel jacks. They're made for the purpose. If you're itching to spend more money, you can just make an extra nice cable instead of getting a molded one. I like Switchcraft's DC plugs.

People generally only talk about DIN connectors in connection with dual and triple voltage supplies. You're right, they have no advantage for your purpose.

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Will standard 26awg SPC do the job for the interconnect or do I need to go with something like 10awg?

For DIYing the cable, I'd use microphone cable. You'll find that the stuff that's thick enough to fill out the hole in the back of the DC plug's shell will also have fairly thick wire.

While even 26 gauge will carry the current you need, heavier wire will reduce the voltage drops, which maintains good regulation. No sense using a good regulator circuit and then inserting an "I/V converter" in between it and the load. No, it doesn't need to be 10 gauge, obviously. But, 22 would make me a lot happier than 26.

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Also, are there any nice looking knobs that will fit on the switch as well as my pimeta alps RK097 pot?

The ALPS pots have 6 mm shafts, while most switches will have 1/4" shafts. But, most decent knobs come in both diameters. All of Kilo's knobs are this way, for just one example.

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Can you make a pimeta have a switchable gain?

Of course. Best to do this with R3, not R4.

 

[mminutel]

When you talk about the "standoff" height of the crossfeed is that the height that the parts stand above the board or is that the amount of space between the pimeta and the crossfeed board. I am not interested in mounting the board onto the pimeta but simply making a separate crossfeed.

To make switchable gain I would just use a switch with double poles right?

 

[tangent]

Quote:

Originally Posted by mminutel /img/forum/go_quote.gif When you talk about the "standoff" height of the crossfeed is that the height that the parts stand above the board or is that the amount of space between the pimeta and the crossfeed board.

Oh, sorry, I misunderstood your question. The tallest part in the current kit is the 0.1uF capacitors, which are right about 1/2" high. You could take that down a bit with creative part mounting.

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To make switchable gain I would just use a switch with double poles right?

Yes. DPDT.

 

[mminutel]

Would there be a problem with this?

I was going to make R3 switchable to 2 and say 8 gain. Then I was going to find a resistor value that would get as close to I could at doubling the gain. So one switch would switch from 2 to 8 and then the other switch would double the other switch to 4 and 16 to make up for the extra gain needed for the corssfeed.. I am making an external crossfeed that wouldn't be taken with the pimeta for my portable ventures but I dont want an extremely high gain all of the time.

The resistance of extra long wires wouldn't need to be taken into account right? It is very small so I imagine it wouldn't.

 

[tangent]

I wouldn't bother making it as complicated as you are planning. I would find a gain that works with all the sources and headphones you want to use without crossfeed, then make the second gain setting double or triple that.

The extra wire length isn't a problem from a resistance standpoint, but it is a risk for oscillation, because it increases the size of the feedback loop. This means that some op-amps that would work with a more traditional PIMETA might oscillate in your planned rig.