Ok,the reason I was asking about impedance matching is that I got a very reasonably priced wireless.The problem is that is for 600 ohms and there's a noticeable drop of hi freq content from the guitar(kind of a built in Woody I guess).
After fidling a while I connected the guitar into the AMZ Booster and that to the transmitter and voila,the hi end is back.
Now I can detect a slight bass loss,very small but noticeable.
I think I can tweak the Booster to give more bass or maybe build the AMZ cab simulator and plug that between the guitar and transmitter or between the receiver and the amp or build a lowZ input for my amp a la Stack In a Box.
The specs are Sensitivity-72dB,Freq Resp-100 to 10.000HZ,Output Z-600 ohms,effective range 15 to 30 meters.No drop out that I could notice and I went all over the house playing.It also includes a headset mic.
Now,I tried the receiver into the Booster but there was a little hiss.
The input Z of the transmitter I don't really know but I gather it's lowZ too.

If anybody can help here,I welcome any input (lowZ please,LOL)
If anybody would like a unit maybe I can get them.The price would be U$55 (tentative price,I have to check the Post Office)shipping included to USA/Canada.With a little tweaking or add-on this could be small gig worthy.
Aharon

Hi Aharon,

Try to increase the output cap of the AMZ booster to 10uF (big step, but it's just a try, 0,47uF or 1uF will do too)

I think this will give you some bass back!

Bye

Joep

PS I assumed you build the AMZ Mosfet booster?

Thanks joep  ,it the AMZ MosFet Booster I was talking about.
I'll try that cap change.
Aharon

Further experimentation yielded better results.By using the Mini Amp or MXR MicroAmp I don't loose any bass at all,as a matter of fact I can't tell the diference basically.
I will build a separate version for this with maybe even lower output Z and lower gain.
How does the 470 ohm and 10K resistor fix the output impedance of the MicroAmp?,if I lower that 10K to say 1K will it be closer to 600 ohms?.

That leaves the output impedance of the receiver.How was it .......low into hi was ok or the reverse?

low output impedance, high input impedance = good.  


Check these out for impedance matching;

http://www.hammondmfg.com/560.htm

http://www.edcorusa.com/sound/matchers/m2m10k_600.htm

google "impedance matching audio transformer" for heaps more.  Include "10k 600" in the search (or whatever values you want) for a more specific result.

Thanks again niftydog.
Aharon

Hi Aharon,

The Microamp has a cap of 1,5uF on the output (15 times higher as the Mosfet booster). The output cap, together with the input impedance (resistor) of your wireless circuit makes a highpass filter, that's why you loose bass. The input impedance of the transmitter and the output cap of the booster are the key influence here.

The 470 resistor is there to protect the circuit against a short circuit between ground and the output of the opamp. This resistor has a direct influence on the output impedance. The 10k does not, because it is paralleled to the 470 in series with the output impedance of the opamp.

A rule of thumb is that you keep the input impedance of a circuit as high as possible and the output impedance as low a possible.

Hope this helps!

Joep

Thanks Joep.MAkes sense now.I measured the impedance of the headset mic and even tho I know that maybe it's not perfect science it measures 1500 ohms so the output Z of the Micro amp is more in line with what's needed.I have no loss now.I will build a dedicated pre for the guitar with a hi quality op,I wonder if the OPA217AP would work in circuits made for regular 4558/TL072 types.Same pinout but they are DiFEt whatever that is.
Any ideas about this?.I know they are supposed to be very low noise.
Aharon

A 5532 will be good, it low noise and capable of driving low impedance.

For other types you have to experiment for yourself what's best....

Bye,

Joep