DI-type device between amp and cab?

[James Nada]

Hi
Is there a device which acts like a DI but sits between and amp and cab? I'm sure I've remember mention of one on BC.

I'm looking at buying an old valve amp but would want to 'DI' the amp sound (and we all know what sound engineers think of micing bass).

Cheers, James

[Andytre]

Pretty sure radial do something like this called the JDX or something, but i think it's for guitar I'm not sure

[Beer of the Bass]

There are a few out there. I've used an old BSS AR116 for this, with the 40dB pad and 4KHz lowpass switches engaged, or something like the Palmer PDI-09 would work.

[dannybuoy]

A few passive DI's have this feature, the Radial JDI does as well. The JDX adds a guitar cab sim though I think, which might not be much use on bass!

[paul_5]

Hughes & kettner red box will do this, but also has a speaker simulator in the circuitry.

[JapanAxe]

The Behringer Ultra-G will take a speaker-level signal (jacks only) and send a balanced output, with or without 4x12 sim. There are two 20dB pad switches to bring the line level down to undistorted levels.

[b]WARNING[/b]: Beware of doing this on a class D amp, as I think I am right in saying that this would cause a short to earth in the power section. Cue magic smoke. Likewise amps operating in bridged mode. I welcome better-informed comment on this!

[Guest bassman7755]

[quote name='JapanAxe' timestamp='1437338932' post='2825202']
[b]WARNING[/b]: Beware of doing this on a class D amp, as I think I am right in saying that this would cause a short to earth in the power section. Cue magic smoke. Likewise amps operating in bridged mode. I welcome better-informed comment on this!
[/quote]

I had presumed that speaker signal level DI's use a transformer to isolate the signal (given that valve amp outputs are generally floating). Still, not something I'd be motivated to try myself just in case and anyway its a bit pointless DI'ing a class D amp output since its going to be the same as the input only louder.

[Passinwind]

[quote name='JapanAxe' timestamp='1437338932' post='2825202']
The Behringer Ultra-G will take a speaker-level signal (jacks only) and send a balanced output, with or without 4x12 sim. There are two 20dB pad switches to bring the line level down to undistorted levels.

[b]WARNING[/b]: Beware of doing this on a class D amp, as I think I am right in saying that this would cause a short to earth in the power section. Cue magic smoke. Likewise amps operating in bridged mode. I welcome better-informed comment on this!
[/quote]

Andy Field from Genz has mentioned those exact issues.

Old Fenders just used a simple resistive tap to ground right off the transformer secondary lead for their line out jack, which works just fine for DI duty IME. Many non-Fender tube amps do use a grounded output config as well. And any amp will have some back EMF downstream of the power section, and the DI will potentially sound at least a different because of that -- not necessarily in a good way though. Harvesting that energy is part of the black art of Class D MI amp design, actually.

Edited July 20, 2015 by Passinwind

[fretmeister]

Marquis Motherlode. It's an attenuator with DI outputs.

[casapete]

Peavey used to do such a thing - the EDI ( Equalized Direct Interface).
Useful bit of kit made in the USA, wish I had n't sold mine.

[Miken]

Hi,

How about the RAT Hotrod. Have a look on eBay as there are a few listed. No balanced DI though it seems, but does load the amp output and provides headphone and line out.

[Jack]

As is my answer to most DI questions, Countryman Type 85. It's perhaps not the planet's best, but it's the standard for good reason.

[funky8884]

http://www.klarkteknik.com/dn100.php

These are cool

[James Nada]

Thanks for all the responses. I'm happy that I have plenty of DI options if I go down the vintage valve amp route.