the legendary tg12412

[thomasdf]

I can access the website, it seems like it's back online. I hope Brian is fine. His site is crazy...  I'll take to time to read it entirely... Lots of informations on it!

Best,

 

[okgb]

Someone had the schematics to build from , did they get posted to our archives ?

 

[thomasdf]

I would be interested to get a look at them if they are available somewhere!
And that TG website is kool... those where great desks...

Thanks,

Thomas

 

[groselicain]

I hate to revive an old thread, but the last two comments were never responded to multiple searches turned up no results. Does anyone have these schematics? abbey road d enfer?

 

[Dylan W]

Found the schematic--posted in Tech Docs.

D

 

[Whoops]

Thank you

 

[thomasdf]

Great! Thanks!
Not we need to figure out the inductors' value....!

 

[gyraf]

If you know the capacitor and the resulting frequency, finding the inductor's value is trivial: http://www.1728.org/resfreq.htm

Jakob E.

 

[JoBe76]

Hello to all 

Does anyone have the "TG12412_schemo.jpg" they could share? in Tech docs i get:
"404 - Attachment Not Found"

Thank you very much.

 

[gyraf]

'tis one?

 

[JoBe76]

'tis one?

Yes, thank you very much
Also thank you for all the great DIY stuff you make gyraf!!

 

[turnerk6]

Anyone still have the schematic in a full size file? Can't tell the details for the inductors from the file posted.

 

[etheory]

Hope this helps:

 

[turnerk6]

Hope this helps:

THANK YOU!

 

[turnerk6]

Is anyone willing to help me understand the low shelf topology/function and how to calculate those frequencies? When I calculate them as LR filters, I'm getting way lower cutoff frequencies than are listed.

 

[abbey road d enfer]

Is anyone willing to help me understand the low shelf topology/function and how to calculate those frequencies? When I calculate them as LR filters, I'm getting way lower cutoff frequencies than are listed.

The nominal frequency of shelf eq's is NOT the turnover ffequency of the associated filters. The listed frequency is where the max boost cut happens, so it's typically about 3 octaves above or below the 3dB point.

 

[turnerk6]

The nominal frequency of shelf eq's is NOT the turnover ffequency of the associated filters. The listed frequency is where the max boost cut happens, so it's typically about 3 octaves above or below the 3dB point.

Thank you! Makes way more sense now.

 

[turnerk6]

Looking between the TG12414 and the TG12412, I noticed some distinct differences with the circuits. It looks like the signal at the first stage (bc109 and bcy71) of the TG12414 are biased to a negative voltage while the first stage of the TG12412 are biased to a positive voltage. Is that accurate? What reason would these two circuits be different when (I assume) they were used in the same desks?

 

[etheory]

I'm no expert but my guess would be to separate the high and low tension/current/noise sections from each other. Putting them on separate rails would give you that.

 

[etheory]

Is anyone willing to help me understand the low shelf topology/function and how to calculate those frequencies? When I calculate them as LR filters, I'm getting way lower cutoff frequencies than are listed.

If I gave you a Mathematica spreadsheet that accurately calculates them as s-domain laplace transforms would that help? The complication here is the inverting stage gain, which shifts the frequencies a little bit compared to a passive circuit.