guitar or bass bone anchored headphone monitor

[mikeydee77]

So I have had great success with my bone anchored headphones. Allows me to have my own private monitor mix when playing open mic sessions. I am deaf in one ear and these are game changers.

But there is an issue that I would like suggestions on how to address. That is that when both the amp and headphones the guitar signal is attenuated a little.

I guess the issue is load impedance related and maybe the best answer is to try a better headphone amp.

The headphone amp is a piece of unknown junk which internally just connects the input via a pot to an op amp.

[Mick Bailey]

Yes, the impedance of the headphone amp is in parallel with the shared input to the guitar amp or desk, so you'll lose some volume and also a little of the top end. Unless you used an active splitter you'll still get this with any two inputs that appear in parallel.

If you wanted to keep your existing arrangement, see if there's a way to easily increase the input impedance of the headphone amp to at least reduce the loading.

I've come across some in-ear monitor amps that have a through output for the guitar that didn't load the signal but right now can't recall the make/model. I need to sleep on it.

[mikeydee77]

Cheers Mick I will look around also.

I did play around with a resistor box on the headphone amp input adding series resistance to the jack tip but didn't seem to make any difference.

[Helmholtz]

You want a buffer before the headphone amp.

[TomCarlos]

Yep, looks like you need a "Buffered ABY Splitter."

You can buy something like the BigShot ABY or... if you are a project guy, our friend R.G. Keen has provided a circuit for this - http://www.geofex.com/FX_images/spltr2.gif.

[Mick Bailey]

I was thinking of the Slow Gear headphone amp as an all-in-one possibility.

Buffering just one input still means the buffer's input impedance is still paralleled and unless it's very high may still be noticeable. A high impedance FET buffer would be OK, either discrete or opamp.

I prefer to use an opamp buffer with 1M input impedance for the guitar input and then split this into two buffered outputs to prevent loading.

[mikeydee77]

You want a buffer before the headphone amp.

Yep makes sense... and it actually does not need to be amazing sound quality as the headphones don't have fantastic top end response.

[mikeydee77]

Yep, looks like you need a "Buffered ABY Splitter."

You can buy something like the BigShot ABY or... if you are a project guy, our friend R.G. Keen has provided a circuit for this - http://www.geofex.com/FX_images/spltr2.gif.

That does look like it would do it although RG Keen might be better as it appears that the ABY is entirely passive and also I would want to build it in to some that can be around a belt / guitar strap or kept in a pocket. .

[mikeydee77]

Thanks for the ideas it definitely seems like the solution is not far a way.

[tedmich]

Yep, looks like you need a "Buffered ABY Splitter."

You can buy something like the BigShot ABY or... if you are a project guy, our friend R.G. Keen has provided a circuit for this - http://www.geofex.com/FX_images/spltr2.gif.

I believe the Radial Twin City ABY (which I own) is the buffered versions, while the Big Shot is passive, the the $90 higher price for the TC reflects this.
I bought mine after I failed getting a Jensen splitter with Edcor transformers to work!

[Merlinb]

JHS buffered splitter is pretty small.
It might also be poissible to change the input impedance of your headphone amp, although from the size of it maybe it is all SMD components?

[mikeydee77]

Hi Merlinb
That looks good. the little headphone amp is from about 1990 and is ordinary components. Input jack goes to PD pot into an amp or op amp and the decoupled and couple of attenuation resistor PD.

Actually you made me remember I have one of those little vox practice amps somewhere which looks a bit like the jhs box

[mikeydee77]

Eureka. This does the job perfectly. my lock down practice amp which had been laying dormant for ages works perfectly no attenuation that I can detect.

Lots of batteries and cables involved but hey ho that is life.

[g1]

I've been eyeing up those bone conduction headphones now, but it seems hard to find wired versions and there are some complaints about latency with the bluetooth wireless types. I wonder if it would be enough to cause issues when playing.

[mikeydee77]

I have a pair of both. Both are made by shokz. The Bluetooth set is very good but never tried it with guitar due to latency. They are about £200 in the UK which i categorise as very expensive. They are aimed at sports scenarios and I think came from military uses of wanting to hear but stay aware.

The wired ones are no longer available from shokz but I found them on ebay £50 new in box. You can get very cheap ones on amazon £25 but no idea how good they are.

The sound quality overall is somewhat like turning the treble down on the stereo somewhat but the advantage for me at least compared with good headphones even before my hearing problem is that I can discriminate notes much more accurately than before. something to do with feeling the music rather than just hearing it.

Recommended finding someway of trying then to see if you like them