Tweed Champ Line Out

[overtone]

Thanks, that link works!
Yes and with regard to transformers, after a comment from KG a while back, I understand output transformers as LR filters.
By the way, are we not in danger of de-railing this thread totally?
Best, tony

[dai h.]

yeah, lol (sorry! In my defense, I will say that this is still related to the general "trying to achieve a decent or good DI'ed tone topic" ).

in re: to the original poster, I think one thing that is incorrect in the thinking to "retain" all the tone out of the spk., is that (in general) you *want* a change oftentimes involving a *reduction* in the information passed. Just because, say you add a tweeter to make sure as much of the information (output freqs.) are passed out of the spk. out, there is no guarantee that it will be "better". It would be sort of thinking like someone is more "pure" because they never shave and get a hair cut, groom, etc. Of course (since this involves art) even if you do something different, as long it meets your goals, I think that is okay too.

[mcgruff]

By the way, are we not in danger of de-railing this thread totally?

That's OK - interesting to know

[dai h.]

(for anybody interested)

this link (article) has an easy formula you can use to work out a target parallel resistor value (to change the damping) :

- Shure SM57 Impedance Modification : Recording Magazine -

edit: (a chart I remembered seeing long ago--found it (finally!))

http://books.google.com/books?id=zsE...A736&lpg=PA736

this has a bunch of links I dug up on the interwebs looking for info on the topic:

Marstran.com ? View topic - low budget cheapskate recording tips

[Steve Conner]

Millions of years ago, when dinosaurs roamed the earth, I made this gadget. A simple speaker simulator

[eschertron]

Millions of years ago, when dinosaurs roamed the earth, I made this gadget. A simple speaker simulator

I've been toying with the idea of adding a line out to a low-wattage amp, so I'm wondering if the speaker is in use (instead of a dummy resistive load), will the frequency filtering effects of the speaker be evident at the primary of the iso transformer? and how much of the speaker color is after the voice coil (physical vice electrical)?

[mcgruff]

From what I've picked up so far, leaving the speaker connected creates an authentic reactive load on the amp but the line out will miss out on the frequency response of the speaker cone & cabinet. Also you don't have the option of different mic positions. These are all important elements in the sound.

If the line out is being fed to a slave, the slave cab gives you all of that back. If the line out went to a DAW, you'd have to use cab sims.

[Steve Conner]

That's what the Weber MASS is: a speaker magnet, suspension and voice coil with the cone removed. You get the impedance peak due to the bass resonance, and the rise at high frequencies due to voice coil inductance: the basic ingredients for an "authentic reactive load".

A real speaker does the same, it just makes a lot more noise in the process. Speakers are so inefficient that replacing the cone with an equivalent dead weight hardly affects the load seen by the amp.

[mcgruff]

The Aiken reactive load was dead easy to build (as was the champ). I'm still getting to know them but it's combination which definitely has potential

Some clips:

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Clean sound, neck pickup. Lead track is set to just slip into break-up when you push hard. This feels very responsive - nice to play:

clean 1

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Volume turned up full:

OD 1

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Volume turned back a bit; clean boost and EQ set to increase mids smashes the pre-amp stage for maximum saturation:

OD 2

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How can something so small sound so huge?!

OD 3

[Tom Phillips]

Sounds good.
How were those clips recorded?
Was it the amp into the reactive load and then a line out direct into the recording input? What was the EQ setup etc?

[mcgruff]

Yeah amp -> reactive load -> DAW.

I'm still figuring out how best to use it. Started with some multi-band parametric EQ but quickly abandoned that when I tried a cab sim - much better.

In the clean sample, I used an impulse response from the JJ powertube set which you can find here. May have used same for the overdriven sounds as well - been doing a lot of tweaking and fiddling to try to find the best tones.

Guitar is an Epiphone dot with some home-made, PAF-ish humbuckers and Jimmy Page wiring. Even with these low-output 'buckers, there's very little clean headroom although that doesn't really matter for recording direct: set the amp gain wherever you like and then set the overall volume with the load box.

[Steve A.]

I'm still figuring out how best to use it. Started with some multi-band parametric EQ but quickly abandoned that when I tried a cab sim - much better. In the clean sample, I used an impulse response from the JJ powertube set...

Can you post the original unprocessed recordings so that we can hear what your amp and reactive load sound like?

Thanks!

Steve Ahola

[mcgruff]

A raw amp line out sounds like crap on its own. I'm not sure if you can really infer anything from that but here's a quick comparison clip. I can maybe do some more if there's something you want to explore.

[Steve A.]

A raw amp line out sounds like crap on its own. I'm not sure if you can really infer anything from that...

Actually that sounds pretty good for a raw amp feed- lots of odd and even harmonics for you to shape and process in your DAW.

So what did you use for the inductor for the Aiken box? Back in the late 90's Randall was using an attenuator like that in his line of amps- I think it was called the Aiken brick.

Steve Ahola

[mcgruff]

Yeah I'm pretty pleased with the sound. I started off looking for a good quality line out / dummy load - mission accomplished

Probably overkill but I used the same coils from ERSE audio that the OP in this thread used for his version of the Aiken load (for a 100W head):

ESQ55-16-10000 1 10.0mH 16ga ESQ - Super Q Coil
EAC32-18-500 1 0.5mH 18ga EQ - Air Core

They're big...!



I would maybe have tried winding my own but was worried about saturation (OP in that gear page thread had some problems when he tried that) so I just stuck with something that I knew worked.