Output attenuator help.

[TheGuitarist]

I've been looking around for output attenuators.. and it seems there are two options. a 1k log pot or a 600 ohm tpdad.

Is there going to be any viable difference between the two? Still not sure if the project i'd be using these on will be transformerless or not so that comes into play as well.

Also if the 600 ohm tpad is a more viable solution, where can i source these or are they only custom units. Thinking of a group buy so i may need a few.

 

[shabtek]

3p4t switch can do rough t-pad
1k pot will generally work alright if feeding lowZ to hiZ---wattage rating might be important.

can we find a way to gang 3 cheep alpha pots?
small lathe to bore out center of spindle...

 

[TheGuitarist]

This is for a preamp output in particular if that helps.

 

[Echo North]

Are you looking for something different than the ones at Hairball or classic API?

http://hairballaudio.com/shop/product_info.php?cPath=27&products_id=33
or
http://classicapi.com/catalog/product_info.php?cPath=48&products_id=106

These are being used on a ton of different DIY builds (as inputs and outputs) and if you look around you'll see the price is very good.

Thanks,

Mike

 

[TheGuitarist]

I did see them, can they be used without an output transformer? I couldn't find a wiring diagram for use without one.

 

[jsteiger]

I did see them, can they be used without an output transformer? I couldn't find a wiring diagram for use without one.

Electronically balanced you mean? I would gather yes they can. As long as what you are driving them with can handle a 600 ohm load. It would be no different than an electronically balanced preamp into an 1176.

Someone please correct me if I am being stupid! 

Cheers, Jeff

 

[Echo North]

I did see them, can they be used without an output transformer? I couldn't find a wiring diagram for use without one.

Electronically balanced you mean? I would gather yes they can. As long as what you are driving them with can handle a 600 ohm load. It would be no different than an electronically balanced preamp into an 1176.

Someone please correct me if I am being stupid!  

Cheers, Jeff

Seems right to me!

Same wiring I would guess.

Mike

 

[TheGuitarist]

So would this be something like this?



+ input  |

                    | - input/output

+ output |

Looking at the switch? I'm only guessing from what the high and low means on the classicapi website.

 

[jsteiger]

Yes if the pot shaft is facing down.

Hi is + and Lo is - so you are correct.

Jeff

 

[shabtek]

look at jlm audio website under schematics for some ideas

 

[mitsos]

NYD also has some interesting designs

http://www.groupdiy.com/index.php?topic=2229.0
http://www.groupdiy.com/index.php?topic=4825.0