Express Power Tubes...

[Paul-in-KC]

Okay - open is good for me. Like you say, the discussion may help others with the same questions.

I have a couple Radial PRO DI boxes. This is a passive with "thru" High-Z that I can feed to my amp (so I get some real amp feel on the original recording). And I take the Low-Z out directly in to my audio interface.

For me at the moment, that is a M-Audio Delta 1010LT.

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Software is Adobe Audition (2.0) - but I think I'm going to swap both out for something that works well together. It's a pain in the butt having to bounce out to the M-Audio virtual console to set levels and route signals.
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Should that be fed into an input with a mic preamp - or just loz-Z no pre-amp?

Definately levels matter especially with an Express.

Then when it comes time to feed the recording through an amp - I have heard of a "reverse DI" box. What do we need there?

As always, many thanks.
-Paul

[overtone]

really appreciate this discussion being open
I am learning here
plus it is a logical development of Paul exploring TW output tubes
best, tony

[Paul-in-KC]

I see that Radial Engineering bought "Reamp" - and (I) found the "Reamp JCR".

Apparently made to do exactly what we want for re-amping.

Taking the balanced output from our original recording pumped out of an audio interface in to the balanced input of the reamper. Then out the Hi-Z output in to the amp.

Piece of cake - I guess.

But I'd have to actually work through the whole process before I actually knew how I would get Audition to play the originally recorded guitar signal and output it on a channel I could route to the JCR REAMP - AND have it record the results of that on one or more tracks depending on how many mics on the amp.

I may want to dump the Delta 1010LT before I attempt this.

Miles - do you use the REAMP JCR (or similar) for "reverse DI"?

-Paul

[Reeltarded]

Mic this thing up with a neutralish kind of one mic thing. 57 about 4 inches out aimed at the middle of the cone wall. Yeah, you can have as many tracks as you have tube combos. I see you losing a weekend to this quickly.

I just go backwards from my rig into the DI low input and hi-z out to amp. I am thinking these reamp boxes are probably just easy ways to route in one box? I haven't paid too much attention there.

This signal gets no preamping, or processing. You are recording signal on a milivolt scale that gets converted back from line level at the output of your converter. Simple enough. I think you already have what it takes to do it.

So your edited test signal is recorded. Route that to an aux output on your converter with the DI hanging off it, and back to your amp. Mic the amp up and start with the testing already!

I love RFT 34s, but I have never been knocked out by an RFT preamp tube, I think this stems from Marshall using terrible ones through the 80s as direct replacements. The spacers are like WAY too small.

Larry (novosibir) is one super cool dood. If I were gonna throw money at a serious amp, he'd be the guy.

If I made sense, excellent. If I didn't make sense blame the fever. I hate being sick!

[Paul-in-KC]

Miles,

Sorry to hear that you aren't feeling well. Hope you back to 100% soon.

So, it sounds like I don't have to have a "reverse DI" box.?.?

As far as I could tell, the main difference between the REAMP JCR and my "regular" DI box, is that the JCR has an "output level" adjustment. It also has a couple of preset filter options and a mute button.

I'm playing in a hockey tournament this weekend, so I may not get a lot done in the next couple days, but I'll try to get a working model as soon as I can.

Thanks.
-Paul

[Reeltarded]

I expected that to be what is a reamp box. That stuff is elsewhere in your rig anyhow, but try not to use it! The idea is matching impednce only. We hope the guitar level recording is going to be at unity gain with the guitar as played.

This might make you get out a screwdriver and go looking through manuals for a trimmer. Probably not. Yay.

[Paul-in-KC]

I think I'm going to have to swap audio interfaces.

A little more reading and I find that all of the analog outs from the M-Audio Delta 1010LT are unbalanced.

So, I should be able to go right from the unbalanced out directly in to the amp (at least I think so). Are there any traps here I am not aware of?

But I think what I want is to have balanced low-Z outs on my audio interface.

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Anyone use an M-Audio Fast Track Ultra 8R?
I think it will do what I want and the version of ProTools that it comes with will run on XP.
I'm pretty sure this is what I am going to order to replace the 1010LT.
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-Paul

[Reeltarded]

Unbalanced. No problem. Continue. Lets see what happens. It's fine.

I LOVE MOTU interfaces with Windows systems. I think we have 10 various models, all very good. But still, run what you brung, and I think you get along just fine.

[Paul-in-KC]

This is interesting (to me)...

I got a chance to try recording a little "raw" pickup signal between work and tonight's first tournament game. And I found that my Les Paul with DiMarzio pickups (36th Anniversary in the neck & Super Distortion in the bridge) can easily overdrive the balanced input in to my 1010LT. I believe that I have the jumper set for microphone level (as opposed to line) inputs.

Do I need to change this jumper so that it's expecting line level input?

Of course I can turn the volume knob down on the guitar and sort-of accomplish the same thing. Except I think I want to be able to operate the guitar controls through their full range without clipping - so I can play back in to an amp with the same wave form that came out of the guitar.

So here's this interesting part. For some reason, the AC wave was not symetrical around 0. Wave peaks were definitely higher (larger magnitude) on the negative side of the signal?

This was most noticeable when the out put from the guitar was "stronger". That is when the volume was turned up (and peaks would clip - on the negative side).

But seems to happen all the time.

Here's a pic...
[in this picture the volume is turned down, so no clipping is occuring]
[IMG826]http://i1178.photobucket.com/albums/x37 ... ession.jpg[/img]


What's going on here? Must have something to do with the conversion to a balanced (differential) signal - but I don't know why

If anyone can explain this that would be great. I am assuming that the signal doesn't look like that coming out of the pickup, but I don't know that for sure either.

-Paul

[Reeltarded]

You are using a typical XLR cable from the DI to the interface?

Expect all kinds of things from a waveform made of clipping. You should see a baritone sax, or a trombone. lol that scares a new producer everytime. Unequal waveforms are natural.

[Paul-in-KC]

You are using a typical XLR cable from the DI to the interface?

Yes - "Regular" mic/XLR cable.

Expect all kinds of things from a waveform made of clipping. You should see a baritone sax, or a trombone. lol that scares a new producer everytime. Unequal waveforms are natural.

What do you mean when you say a waveform made of clipping?

Sounds like asymmetrical sound waves are the norm from natural sources.?.?

In the little bit of digital recording that I have done in the past (which isn't all that much). I don't recall seeing this sort of obvious asymmetry.


ANYWAY - thinking about this a bit more. I need to get the input gain/signal level down below the point of saturating (because I don't want to distort what is coming out of the pickups - we want the amp to do that when we feed it the raw signal).

I see this is conceptually simple, but getting all the details right in the recording rig is tedious (for anyone that doesn't know their recording gear inside and out - like me ).

I think if I change the jumpers on the Delta 1010LT to set the balanced inputs for line-level that will eliminate the mic preamp and probably give me what I want (as far as the signal path on the way in). Does this sound right?

Of course changing the jumbers is a pain in the back side, so another reason to switch interfaces (can you tell I want a new interface?).

-Paul

[Reeltarded]

aha mic amp bypass.. maybe.

Yes.

[Paul-in-KC]

Well - here's the progress report on reamping...

I did get a new audio interface. It's an M-Audio Fast Track Ultra 8R.

No doubt - I didn't have to have a new interface to get this to work, but it's a LOT nicer having all the "adjustments" outside the PC (and not as a jumper block on a card inside your computer).

So - in the "raw recording" phase, you want to record straight in to a wav file. No mic preamp.

DO adjust the input gain so that the maximum output from your guitar (hard open E chord with vol on 10) doesn't clip.

One nice feature of the Fast Track Ultra 8R is that you can select inputs 1 and 2 as instrument, line, or mic. This eliminates the need for a DI box on the original raw recording.

This is nice, but not a huge benefit, since you will need a DI when you want to output the raw -> in to your amp.

Once you have your raw guitar recorded - you will need to have this "track" in a "mix" or "multi-track" view in your recording software so that you can route this track to an output channel.

You want to route this to the output channel that you have plugged in to your amp.

If you have a high-Z output, you can go straight from there in to your amp. But in the more likely event that your output is low-Z balanced - you will need to route this into a DI box and then make your high-z connection from the DI box to the amp.

At this point, you should be able to "play" your wave file in to the amp.

Start with the volume slider down low and ease it up - just in case you have more signal there than you should. Bring the volume slider up to give you the amount of input signal that you want and you are good to go.

Now, just put a mic on another track and record.

NOTE: I really like the FT Ultra 8R, but the Pro Tools SE software that comes with is useless for reamping. I'm not absolutely certain (yet) - but it seems that SE doesn't have the ability to route output. I already had Adobe Audition - which works perfectly fine with the Ultra 8R ASIO driver - so that's what I used.

Now - to create a little collection of raw source and start creating some A/B comparisons of tubes (and more).

-Paul

[Reeltarded]

Yay! And away we go! We should get a set of test tracks so we have a baseline for everyone to test from.

[Paul-in-KC]

Yay! And away we go! We should get a set of test tracks so we have a baseline for everyone to test from.

I thought about that too. I think that's a great idea.

It would be nice to have a virtual collection of guitars to play through your creations - plus a variety of music styles.

One thing that would be hard to calibrate though - is the signal level (peak-to-peak). Not sure how we would calibrate that without the use of oscilloscopes (maybe most folks here have one???).

Of course, no calibration required for someone to play with the clips on their own gear (i.e. not trying to compare with other clips recorded through an amp).

You got some raw guitar waves ready to post?

I think we would want to identify the guitar, pickups, volume and tone control settings, maybe strings or string gauge.?.?.?

I suppose these should be posted in a thread under the "files" board?

BTW - I think the size limit is 5MB which means posting fairly short clips.

-Paul