mjrippe

Re: GDIY passive 'Mojo' box
« Reply #40 on: November 04, 2020, 01:57:26 PM »
That one is an active box.

Not according to the description, Ian. 

"Yes! it really is a passive based design. Obviously the indication lights and meters are active, but the audio circuit itself remains true to a completely passive analog design. "


ruffrecords

Re: GDIY passive 'Mojo' box
« Reply #41 on: November 04, 2020, 06:00:16 PM »
Not according to the description, Ian. 

"Yes! it really is a passive based design. Obviously the indication lights and meters are active, but the audio circuit itself remains true to a completely passive analog design. "

Aha! I was misled by the 'output stage' and the SOVT, thinking there was a Russian tube in there. You are right it is 100% passive. From the lengthy description it seem to be incredibly complicated but then you look at the controls and they are very simple. Good marketing speil I think, I have read it through carefully and sketched out a block diagram of what is in it. Not 100% certain because the description is woolly in places but some useful info nonetheless.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

craigmorris74

Re: GDIY passive 'Mojo' box
« Reply #42 on: December 17, 2020, 03:59:59 PM »
I reading about these circuits I keep running into descriptions of using feedback with a transformer in a passive setting.  How could that be incorporated into a device like this?

ruffrecords

Re: GDIY passive 'Mojo' box
« Reply #43 on: December 17, 2020, 05:22:33 PM »
I reading about these circuits I keep running into descriptions of using feedback with a transformer in a passive setting.  How could that be incorporated into a device like this?

I have never seen mention of feedback from a transformer in a passive setting but it is often used with an active driver. Can you give us a pointer to an instance where it is mentioned in a passive context?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

craigmorris74

Re: GDIY passive 'Mojo' box
« Reply #44 on: December 18, 2020, 09:26:23 AM »
I have never seen mention of feedback from a transformer in a passive setting but it is often used with an active driver. Can you give us a pointer to an instance where it is mentioned in a passive context?

Cheers

Ian

Hey Ian,

The guy on Gearslutz you mentioned in the original post has said feedback was the key to his device. 

ruffrecords

Re: GDIY passive 'Mojo' box
« Reply #45 on: December 18, 2020, 04:12:37 PM »
Hey Ian,

The guy on Gearslutz you mentioned in the original post has said feedback was the key to his device.
I have been unable to find anywhere he says this. Can you post a link please?

Cheers

ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

craigmorris74

Re: GDIY passive 'Mojo' box
« Reply #46 on: December 18, 2020, 06:55:58 PM »
I have been unable to find anywhere he says this. Can you post a link please?

Cheers

ian
https://groupdiy.com/index.php?topic=70421.20

Post 35

ruffrecords

Re: GDIY passive 'Mojo' box
« Reply #47 on: December 19, 2020, 05:07:04 AM »
https://groupdiy.com/index.php?topic=70421.20

Post 35

Ah, right. He sounded really annoyed in that post. I am not sure what to read into that comment.

Edit: It turns out that you can represent any system, even a passive one, as a feedback system:

https://electronics.stackexchange.com/questions/78859/negative-feedback-with-only-passive-components

But I am not sure of its usefulness.

Cheers

Ian
« Last Edit: December 19, 2020, 05:15:33 AM by ruffrecords »
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


 

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