V672X (Telefunken V672a in GDIY51X format)

[fragletrollet]

What settings would be used for line levels, if suitable? Would any of the gain settings be close to unity?

 

[[silent:arts]]

What settings would be used for line levels, if suitable? Would any of the gain settings be close to unity?

You would choose
S1 =  dB Gain: 41dB / R Gegenkopplung: 12K
S5 = dB Input: -40dB / R Eingang: 24K
The trimmer R26 should be fine to adjust that one dB difference

 

[fragletrollet]

Cool! Would be nice if the frontpanel reflected this, but i wont complain  ;D

 

[[silent:arts]]

Since I do individual front panels we can add this to yours, no problem

 

[kante1603]

Hi Volker,


excuse me chiming in,but I think what fragletrollet meant was writings in decibels instead of resistances?


Best,


Udo.

 

[[silent:arts]]

Everything is possible, international dB version attached 

 

[kante1603]

Hahaha...very nice indeed ,but I'll stick to german  ;D


Udo.

 

[fragletrollet]

Nice!! Someone needs to get himself a +24v rack

 

[Potato Cakes]

Hahaha...very nice indeed ,but I'll stick to german  ;D


Udo.

I second Udo. It really adds to the uniqueness of this project. I don't recall anyone having issues with German words used on vintage Telefunken gear.

Just my two cents.

Keep 'em coming, Volker!

Thanks!

Paul

 

[[silent:arts]]

Just want to show you two custom front panels I did today.

 

[kml23956]

Volker,  The radial diodes d41 -d44. Which way is negative? How do I put them in?

 

[kante1603]

Hi,
look here at the lower left side of the page:
http://www.silentarts.de/DIY/V672X/V672X_rev03-PCBs.pdf
The black bands of the diodes show upwards.


Best regards,


Udo.

 

[[silent:arts]]

Like Udo said. All diodes up 

 

[kml23956]

Thank you. I could not figure that one out. Everything else is well marked. The thing is designed to be built like a tank!

 

[mtw]

Greetings Volker,

Is there a way to calibrate this unit with a multimeter? I'm afraid I don't have an oscilloscope.

Cheers,

-mtw

 

[[silent:arts]]

You don’t need an oscilloscope. But I won’t use a Multimeter either.
The metering in your DAW should be enough for calibration.

 

[mtw]

You don’t need an oscilloscope. But I won’t use a Multimeter either.
The metering in your DAW should be enough for calibration.

OK - thank you!

 

[coledingo]

Aside from using a daw, what sort of machine would you use for calibration?

 

[[silent:arts]]

A signal generator. And a VU meter.

 

[coledingo]

Pardon my ignorance but another stupid question incoming... I just want to make sure I'm understanding this correctly.

for calibration there are three steps:

GAIN ADJ R26:
Generator = 1kHz -40dBu
Set R26 to measure +2dBu

HF ADJ R37:
Generator = 15kHz -40dBu
Set R37 to measure +2dBu

LF ADJ R29
Generator = 40Hz -40dBu
Set R29 to measure +2dBu

where generator is set as indicated and sent to audio in, and then you adjust the respective resistor until you measure the indicated dBu of the audio out with a VU meter? and for each of these steps the unit would be set as:

S1 = dB Gain: 62dB / R Gegenkopplung: 240K
S2 = LPF OFF / Tiefpass Überbrückt to left position (on)
S5 = dB Input: -20dB / R Eingang: 2k2

Is this all there is to it or am I way off?