Desktop IEM amp

Agreed! I think many CIEM or just regular IEM owners would be interested in something like that.

 

How can we make this happen?

 

As you can see, it is basically designed. I would just need to figure out pricing and take some orders. The only rub is tracking down JFETs, but I assume quantities are low enough that it will not be too hard.

 

Can someone explain what a buffer is in layman's terms?

 

A buffer provides current but no gain and a low output impedance. For instance, the output of a DAC has sufficient voltage to drive many headphones to very loud, but it may not have enough current to back up that voltage into a low impedance like headphones, and it may lose voltage across the output.

Some math - assume you have a source that can output 2V. Into a preamp, or headphone amp with an input impedance of 50K Ohms, which is typical, the source has to provide (V=IR -> V/R = I) about 2/50000 = 0.00004 Amps, or 0.04mA which is not much. Into a 300 R load, that source would need to provide 2/300 = ~7mA. Still not much, but more than many sources can provide. Into 32 Ohm phones it is 62mA which is actually quite a bit.

Additionally, sources tend to have a high output impedance which means that, among other things, they will drop voltage across the output. If your source has an output impedance of 600 Ohms, into a 300R headphone load, the output essentially sees 900 Ohms (300 + 600.) That forms a voltage divider which means that of the 2V output, only 1/3 or about 0.67V will actually go to where you want it. Into the 50K load, the 600R output impedance is only ~1% of the total load so very little of the 2V (~0.02V) would be lost which is incidental.

The reason you might want a buffer is that gain adds noise and distortion. If you already have enough signal form your source (say 2V is all you want) then using an amp with 5X gain you would first need to cut your 2V signal down to 0.4V (with the volume pot) only to reamplify it with you amp. This is a recipe for bad sound, though it is what almost every system does. That is to say, if you are not using your system turned up almost all the way most of the time, you have too much gain.

 

What would be your speculative price range for such a device? Perhaps we could compile an interest list. Super buffer audio friends...

 

I'm aching to throw my money at something but Leckerton Audio is still sold out, damn.

 

How recently did you check? Website says ships in 1-3 days: http://www.leckertonaudio.com/products/uha-6s-mkii/

 

Mother F--- I checked literally last night, whelp, looks like it's time to bite the bullet.

 

In small quantities, I'd say it would be in the $1200-1400 range with an off the shelf switching supply, add $200-300 with a linear supply (which I am not sure really sounds any better.)

 

I have to admit, that is a little more than I anticipated. On the other hand, I assume this would be the 'ultimate' 'end game' 'wire-with-current' 'transparent' etc etc IEM amp...

Would you require a minimum order number to consider production?

 

Not very many. And since the cases would be powder coated, each one can be any color for which is there is a RAL number.

 

Isn't a amp with gain of 1 basically a buffer? If so why not just get a Mjolnir 2 or another amp with a 1x gain. Maybe Jason can shed some light on how 1x gain Mjolnir 2 works.

 

In balanced mode. In normal unbalanced there is faint noise on lowest gain.

 

would it be easy to lower the gain myself? I dont really know where the resistors required are located in the amp and can't really open mine as it is not with me atm. will get it back in a few days. I know how to solder but I am not great at precision stuff if its like SMD.

anyone who has done it before?

 

The original buyer of the IEM buffer I made is selling it due to financial difficulties. If anyone is interested, I'll be happy to put you in touch.

 

O2 with unity gain

 

Thanks, that cleared up A LOT. I was mulling over trying a 12.8ohm IEM, but I can see that would pull 156mA across 2V which I can't see any line out FET willing to push.