GDIY passive 'Mojo' box

[cpsmusic]

..have you heard what this does to your material, and are you sure you actually like it's contribution?

I'm a long-time rock guitarist so I'm more than familiar with different types of distortion!

I've been working in audio production for the past couple of years and from what I've seen so far, distortion (or "saturation") is used more-or-less everywhere (other than classical and acoustic styles but even there sometimes) - Neve Silk, HG-2, Silver Bullet, NGBusComp, Michelangelo, Overstayer, Fatso, the list goes on.

The key of course, is to use it appropriately.

Cheers!

 

[warpie]

As discussed earlier in this thread, series resistance in the primary will increase distortion.

Cheers

Ian

Probably a silly question but would this magnetize the core?

 

[leadbreath]

I'm a long-time rock guitarist so I'm more than familiar with different types of distortion!

I've been working in audio production for the past couple of years and from what I've seen so far, distortion (or "saturation") is used more-or-less everywhere (other than classical and acoustic styles but even there sometimes) - Neve Silk, HG-2, Silver Bullet, NGBusComp, Michelangelo, Overstayer, Fatso, the list goes on.

The key of course, is to use it appropriately.

Cheers!

If you think youre going to party on the Neve Silk unit like a fuzzbox u will be bitterly disapointed. I've used it numerous times and its quite subtle....bit disapointing to be honest.....

 

[ruffrecords]

Probably a silly question but would this magnetize the core?

Not at all. Standard models of a transformer include a non-linear resistance across the primary winding. If you drive the transformer with a very low source resistance (like an op amp), this effectively shorts out the non-linear one thus reducing distortion and at the same time extending the low frequency response. This is what allows many manufacturers to get an apparently decent performance out of an essentially crappy transformer. We want to do the opposite so we increase the source resistance so the non-linear resistance can do more of its thing. And incidentally we get a worsening of the low frequency response at the same time.

Of course, if you are designing with tubes, really low source impedances do not exist, so you will 'hear' more of the transformer's intrinsic distortion. Maybe that is one of the factors that leads many people to prefer the 'sound' of tubes.

Cheers

Ian

 

[cpsmusic]

If you think youre going to party on the Neve Silk unit like a fuzzbox u will be bitterly disapointed. I've used it numerous times and its quite subtle....bit disapointing to be honest.....

Yes, I realise they're quite different in terms of sound (and application).

 

[john12ax7]

It depends on which silk. The red and blue on the 542 tape simulator wasn't that subtle. But it also seemed to have some EQ going on.

 

[leadbreath]

It depends on which silk. The red and blue on the 542 tape simulator wasn't that subtle. But it also seemed to have some EQ going on.

Suppose it depends on your definition of subtle........?

 

[Nen'O]

I did some research and tested few device, Phoenix Audio seems to make the best studio tools for that purpose.
People don't speak often about it but Phoenix Audio N-8 DI make excellent 8 channels colour box. It doesn't have input gain knob but still you can send hot signal and overdrive output transformer and trim output to desired level. If someone comes up with input gain mod N-8 DI it would be great.
Nice DI is 2 channels option.
It comes to about 200$ for a channel.

Spl charisma 8 and 2 are tube version colour box. There are mod instruction somewhere on the web but even stock if used right sounds very good.
Charisma in discontinued.


I used to own Neve 5042 Line Amp/Tape FX beautiful device but sold it recently to buy another Phoenix audio drs-q4 mk2 preamp. Drs-q4 mk2 does similar thing as Neve 5042 when you push output just a touch plus it has killer EQ and preamps.

There is similar thing already available and the price seems to be right

https://www.diyrecordingequipment.com/products/ctx-cinemag-transformer-colour-mkii
If anyone has some input about CTX Transformer Console Colour it would be great.

General rue for all analogue colour boxes is that things can easily be overcooked and sound bad, as well for use in stereo it needs to be carefully calibrated before final print or things get out of phase.

 

[cpsmusic]

Interesting that you mention the CTX - that's one that I've looked at. It's meant to emulate the input stage of an API console.

I was also looking at another of the DIYRE colour modules (the JFT) but decided that the shipping costs were a bit high (around $US40.00). I was thinking of building the JFT anyway however it uses a 2SK170 which are a bit hard to get.

 

[Script]

Spl charisma 8 and 2 are tube version colour box. There are mod instruction somewhere on the web but even stock if used right sounds very good.

When stock, isn't the charisma 'just' diode clipping followed by a tube ?

 

[cpsmusic]

I'd like to push ahead with this project, so I picked up some cheap transformers for experimenting:

https://www.ebay.com.au/itm/335100968673
Cheers!

 

[Ricardus]

Cool. Keep us posted.

 

[cpsmusic]

It's been mentioned in various places that a DC offset on the primary can be a useful addition - just wondering what sort of values would be a good starting point?

Cheers!

 

[gyraf]

..something where your offset plus the ac voltage in question adds up to a level comparable to the saturation point of the core and the number of turns you have at hand..

(i.e. easist to determine experimentally)

Note, that you'd probably NOT want to mistreat ni-core transformers this way, will probably damage them more or less permanently

/Jakob E.