A twisted tale about a logarithmic relay attenuator

Status
Not open for further replies.
Re: Joshua + AC1 & Femto

wirewiggler said:
Ok Russ,
You have dragged your feet a long time on this, do you care to share with us what is going on?

Thanks
Bill


Hi Bill.

I am very sorry to keep you waiting. Its not intentional. A couple things.

1) There was a defect in the first run of AC1, that has been fixed just awaiting new boards.

2) Brian has been head deep in general life stuff (getting a home ready to sell etc) so I have been waiting for things to get back up and going before I flood him with new stuff. 🙂

On a positive tone, its all been tested, and I know that it all works.

We also have decided to offers a very cool little controller called "volumite" that can be used as a simple controller (with volume) It consists mainly of a pot and a AVR ATtiny85.

This is the solution intended for those who just want simple volume control for JT, Buffalo, Opus etc.

Cheers!
Russ
 
Russ White said:
Its exactly the the same very popular Joshua Tree cct with mute added. 🙂

It is actually pretty near universal.

If your particular source requires a constant input impedance I would suggest a buffer in font of the JT. 🙂

Cheers!
Russ


I can't think of a less universal volume-control, that has variable input impedance...???
(almost like a pot wired "backwards"...)
And will be useless as a passive.

Arne K
 
Cobra2 said:



I can't think of a less universal volume-control, that has variable input impedance...???
(almost like a pot wired "backwards"...)
And will be useless as a passive.

Arne K


Arne, sorry, but your statement does not make any sense. Your proposition that the attenuator is not useful passively falls flat on its face because we know that hundreds of people have found the circuit extremely useful, and many of them use it passively. 🙂

This is not a new or unproven circuit, it is solidly proven and tested.

But, In fact the constant output impedance also works extremely well into something active like a THS4131 where you can use the fixed output impedance to calculate the overall gain.

All you really need is a source that is capable of driving the lowest impedance of the attenuator. Such a source is very very easy to find. 🙂

If you don't find it useful, well then that is what it is. Go use something else and be happy.

Peace.

Cheers!
Russ
 
I really don’t have any fancy equipment or advanced electronic skills, but I would like to know if an attenuator is what I need to connect an amplifier to a tape recorder to record quality sound? I’ve looked at attenuators at electronic stores without being able to identify the differences between them, and I would appreciate anything that you could tell me about what type of part I need to make this connection, if not just a cable. I got a little worried about using just a cable because I thought that I might blow the tape recorder or not record as high quality sound as I could. I’m impressed by your sophisticated device, but would be grateful for a description of an already made part.
 
wirewiggler said:
getting a little testie Russ? I am to assume the volumite is a substitute for the rotary encoder ? Any luck with Joshua boards? At least I could get that started, until you get the AC1 and Femto sorted out.

Thanks
Bill



Volumite is a stand alone controller. It will work with the relay driver to drive one or more JTs. 🙂

The JT boards are done, we just have a revison to make on the driver and AC1 boards. The Volumite boards will be coming at the same time.

Testie? Meh, just slightly annoyed. I just love it when people say that something that people use every day for a given purpose is not suitable for that purpose. 🙂 But in reality it honestly was good for a hearty laugh on this end.

Cheers!
Russ
 
Hi,

It seems that following the website redesign, the docs folder has gone walkabout - is there any chance of you reposting the JT single sided board layouts (oh, and the programmer circuit and layout, too)? I'm really interested in giving one of these a go.

Chris
 
Re: Re: Schematic and source code

Erlend S�terdal said:


I didn't think you would need help for that Hurtig. I thought you where a competent designer yourself.



😀


It will be available in any case.

The attenuator cct is incredible simple though. Just a logarithmic series of L-pads. Each Lpad is calculated for the output impedance of the LPAD preceding it.

There is also a relay for mute.


The firmware is also very very simple.

Cheers!
Russ
 
Status
Not open for further replies.