Mallory T600 Audio T-pad, 4 Watts (15W Audio) for REDD 47

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

aaquilato

Well-known member
GDIY Supporter
Joined
Feb 3, 2012
Messages
73
Hi all.
I hope everyone is well as can be during the crazy time we're all going through.

The REDD 47 discussions have all but evaporated. I guess I'm late to party.
Now that traveling for work is not an option, I'm finding the time to get unfinished projects started again.

I've boldly (with no EE schooling at all) taken on the DRIP Ultra 47.
Oh boy. Talk about pages missing. I can't wait to feel what 300V feels like.

About the T-pad.
I don't have the model number but here are some notes about it.
Mallory T600 Audio T-pad, 4 Watts (15W Audio)

The range of attenuation (not mentioned in any of the Mallory spec sheets). 
Measured resistance of the three (wirewound) sections of the attenuator and found:  the outer sections are 600-ish ohms and appear identical, as they should be.  The center section ranges from about 1 ohm (max attenuation) to about 12 megohms (min), and has a very steep non-linear taper.  The very high maximum resistance implies the minimum attenuation is very close to 0dB.. max attenuation would require a careful measurement.  Estimate about 60dB from the resistances..


Would the T Pad listed above work with this build?

Anyone wanting to open up a dialog is welcome.

Thanks all.
Anthony.


 
They work pretty well in one of two Drip 670 v3. So I guess they will work in the Drip 47 as well.
And I guess you have to wire them the same way as on the 670v3.

Greets
 
Pusch3l said:
They work pretty well in one of two Drip 670 v3. So I guess they will work in the Drip 47 as well.
And I guess you have to wire them the same way as on the 670v3.

Greets

Thanks for the reply. I haven't received it yet.
How is it wired?

AQ.
 
As from factory the middle pins soldered all together. The middle taper goes to the "com" point. The taper near the frontpanel is Input and the last taper goes to output into the circuit IIRC. But I can look that up. You have a Screenshot of the PCB where the T-Pad must be wired up?
 
Pusch3l said:
As from factory the middle pins soldered all together. The middle taper goes to the "com" point. The taper near the frontpanel is Input and the last taper goes to output into the circuit IIRC. But I can look that up. You have a Screenshot of the PCB where the T-Pad must be wired up?

Hi Pusch31.
Thanks for replying.

I'm attaching two screen shots. One of the full pcb and another of the T-pad wiring, which looks pretty straight forward.

I will not be adding +48V to this build so I'm going to assume that I will not need the resistors outlined in the 2nd screenshot.

There is a note in the "Four Seven" build documentation, not the "47 Ultra" documentation  about changing the value of the capacitor for the low cut filter. I only mention this as it is in the screenshot.
1uF for POP vocal.
2uF for ROCK vocal.
How do I calculate the actual freq? Let's say 80Hz & 160Hz?
I was going to use a three position switch to give me the two different options.
One more of a rumble filter. The other a more natural hi-pass filter.

And again I will say, with no EE background, little things like this are a stumbling block for me.
So thank you for your help.

AQ.
 

Attachments

  • Screen Shot 2020-06-20 at 8.56.02 AM.png
    Screen Shot 2020-06-20 at 8.56.02 AM.png
    74.8 KB · Views: 47

Latest posts

Back
Top