Can Someone Please Make a Small Gizmo for Me?

peteri

Hi

I need a small box which will have a 1/4inch jack input, two 1/4 jack outputs and a switch.

This will take the speaker out from my amp and depending where I set the switch either route the signal straight out to one 1/4 jack (to go to the speaker) or through a 16ohm load and to a line level out of the other jack (muting the speaker).

Hopefully that makes sense, anyone able to either build one or let me know someone that could?

Thanks

Pete

ecc83

NOT! That I am offering Pete! (my soldering days are passed) but can we pin the design down a bit?

Do you already have a 16 Ohm load box? I assume not but then the builder will need to know the amplifier brand and model to get an idea of the ultimate power it could put out, e.g. "our" Stage 60 comfortably kicks 80watts and seriously overdriven would deliver near 100W.

The line out? Level? +4dBu, 0dBV or neg ten? And at what amp volume level do you want that OP level? (easiest to make it variable)

Gets tricky don't it?

Dave.

peteri

Dave

Thanks no I don't, and mine are behind me too!

This will be for a 30watt valve amp (Peavey Classic).

Line out - good question, basically whatever the standard is for guitar pedals to call line level.

And on the variable - again good spot, guess I need a pot there to adjust the volume.

Bugger!

Danny1969

A pure resistive load in a box with the jacks, switch  and line out  volume pot would be about £80 built. A make before break switch would be a good idea meaning the OT was never without a load if you switched it while turned on. 

It's not a lot in parts but a bit of labour in terms of drilling and wiring hence the cost

Arkless_Electronics

To be clear then, you need this to include the 16 Ohm load etc? It's not just a box with 1/4" jack in, 2 x 1/4" jack out and a switch to select which output jack is connected to the amp?

peteri

Yes - I need the load too.

ICBM

What you want is a Weber MiniMass 50W. It has a bypass switch and a line output jack. Set the volume to minimum and the bypass switch will effectively give you the speaker/load switching.

Buying one (especially second hand) will probably be cheaper than having someone build one for you to the necessary standard.

Arkless_Electronics

peteri said:

Yes - I need the load too.

About £80 seems right then. I can also do this for you.

peteri

thanks for the advice, great to have that £80 in my head - and good to know I have someone.

Let me do a little research and I'll be in touch - thanks again for all the help

ecc83

Danny1969 said:

A pure resistive load in a box with the jacks, switch  and line out  volume pot would be about £80 built. A make before break switch would be a good idea meaning the OT was never without a load if you switched it while turned on. 

It's not a lot in parts but a bit of labour in terms of drilling and wiring hence the cost

I really wouldn't worry about a MBB switch Dan. In hundreds of amp testing hours I have had rigs that flipped speakers/loads scores of times on each test, often with the amp at full welly. Then there have been the chance "unloadings" under sine or noise drive, again often at max crank.

I you are REALLY concerned you could have a permanent load of say 3X the rated LS impedance connected or just a 220nF or so cap across the live contacts of the switch.

Err Mr A, does that 80 quid include my commission?

Dave.

Danny1969

@ecc83

I know and your right but it's the right thing to do even if unnecessary. Your commission is a virtual pint