[nikongod]

 
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Certainly looks interesting
 
http://www.tubecad.com/2007/04/blog0102.htm

Thanks.
 
The new ones he sells have smaller steps & better switches, if Im not mistaken.
 
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Worst case, yes.

What makes a potentiometer the worst case solution in comparison to other resistive volume controls?

 

[nullstring]

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The new ones he sells have smaller steps & better switches, if Im not mistaken.

http://glass-ware.stores.yahoo.net/netcjstat.html
 
Those are the new ones.
EDIT: there is also a new one, with expensive boutique switches, if that's what you meant.
http://glass-ware.stores.yahoo.net/tcj-stepped-attenuator.html
 
I kind of wish that it didn't have separate controls for left and right.
A similar design with two or three switches which are all stereo would certainly be interesting.
Cheap alternative to one those other stepped Attenuators

 

[nikongod]

 
Quote:

 
I kind of wish that it didn't have separate controls for left and right.
A similar design with two or three switches which are all stereo would certainly be interesting.
Cheap alternative to one those other stepped Attenuators

I think he designed it more for speakers. The gain structure of most headphone systems is hopeless with only 40db of control....
 
I have the less expensive kit in one of my (inspired by the MHSS) amps. You get used to 3 knobs really quick. The whole thing is nice and short when its built, which is great for short chassis.
 

 

[JB197]

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Another option for me is to add a buffer but I'm still not sure which one I should use.

Yup you certainly could do that. Just make sure it has high-ish input Z, a low-ish ouput Z and is happy to drive 2k2.
 
But, honestly, that's getting complex and it's a bit like sticking a big plaster over a smaller plaster. It's going to be much more simple and more effective to not fit the JT and instead use the Tent Labs kit or a conventional attenuator / potentiometer.  
 

 

[ujamerstand]

wait, the tentlab stuff is based on the attenuator by jos van eijndhoven, right? He had a schematics and calculators on his site that allows you to calculate the values of the resistors you need. I remember looking at the schematics and wondering how similar it looked to the joshua tree, couldn't we just modify the JT? I basically had the same idea as OP, and bought myself JT boards with the intentions of changing resistor myself, I even had a BOM setup here. Haven't got a chance to follow through with the plan though. Is this really a bad idea?

 

[Lil' Knight]

Quote:

wait, the tentlab stuff is based on the attenuator by jos van eijndhoven, right? He had a schematics and calculators on his site that allows you to calculate the values of the resistors you need. I remember looking at the schematics and wondering how similar it looked to the joshua tree, couldn't we just modify the JT? I basically had the same idea as OP, and bought myself JT boards with the intentions of changing resistor myself, I even had a BOM setup here. Haven't got a chance to follow through with the plan though. Is this really a bad idea?

Yes, the JT is also based on Jos schematics but I'm not 100% sure if his calculator would work fine with the JT.
What's the input impedance of your Mouser BOM?

 

[ujamerstand]

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Yes, the JT is also based on Jos schematics but I'm not 100% sure if his calculator would work fine with the JT.
What's the input impedance of your Mouser BOM?

 
 
 
Well crap. Forget about my BOM. Did a bit more research and what I had would give you a 50k constant output impedance and variable input impedance. and well, what I learned from this thread is that it might not be desirable... There's this that can provide constant input impedance. The same circuit is described here and the values are attached, but with my limited understanding I cannot figure out the difference between this and the jos schematics. -_-
 

 

[amb]

Or wait for LCDuino1 + δ1, which has constant input Z. 

 

[Lil' Knight]

I feel regretful for not waiting for the Delta-1 but my time is quite tight. I might leave the JTA for other project though.
 
I know I already ask this, but to make sure again, would the Delta-1 work alone just fine, without the LCDuino1?

 

[amb]

Quote:

I know I already ask this, but to make sure again, would the Delta-1 work alone just fine, without the LCDuino1?

δ1 is designed to be controlled by a microcontroller, which is what LCDuino-1 is.  If you want to design an alternate controller and write firmware for it, then yes, you could theoretically make something else work with the δ1.  But it will not work "standalone".

 

[Lil' Knight]

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  If you want to design an alternate controller and write firmware for it, then yes, you could theoretically make something else work with the δ1.  

I doubt I could
 

 

[nullstring]

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δ1 is designed to be controlled by a microcontroller, which is what LCDuino-1 is.  If you want to design an alternate controller and write firmware for it, then yes, you could theoretically make something else work with the δ1.  But it will not work "standalone".

Will you be releasing specifications on how the delta-1 is controlled?

 

[ujamerstand]

 
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Or wait for LCDuino1 + δ1, which has constant input Z. 

Awaiting for the first firmware release. Will there be a git repository, or any kind of repository available through which we can contribute code back in the future?
 

 

[amb]

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Will you be releasing specifications on how the delta-1 is controlled?

The schematic and official firmware source will be open source, and that should be enough documentation.  The interface is I2C.
 
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Awaiting for the first firmware release. Will there be a git repository, or any kind of repository available through which we can contribute code back in the future?

 
I don't know what form of code feedback we'll set up yet, but as it stands we're approaching the limit of the ATMEGA328 chip's available memory so we can't add much more code (in fact we'll have to slim it down).  You are of course free to modify the code to use as you wish.

 

[Lil' Knight]

So basically, what'd be an ideal input impedance for my source? Would a 25k pot do the job fine or I need a 50k one?