DIY passive Re-amp box? (+4dB->hi-Z)

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http://www.unitedmusicians.info
Contributor Since: Nov 11, 2007

I'm looking for a great DIY passive re-amp box. Hoping to keep it under $100, and want to use one of those combination XLR/1/4" inputs with a 1/4" hi-Z output (like on the ReAmp v2, www.reamp.com/). Know of any off the top of your head worth looking into?

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The Czar of BS
Member
Since: Dec 31, 2007


Jun 01, 2011 09:01 pm

Passive re-amp???????

How do you passively re-amp something?

Are you looking for a line amp? Something that takes an amplified signal and boost it out for a long run?

Sorry, your link isn't working, so I'm not 100% sure what you're looking for.

www.TheLondonProject.ca
Member
Since: Feb 07, 2005


Jun 01, 2011 10:08 pm

www.reamp.com/

www.reamp.com/home_images/home_reamp.jpg

www.reamp.com/faq_images/V2_inside.jpg

All I have time for. Back to the game. Go Canucks Go!

The Czar of BS
Member
Since: Dec 31, 2007


Jun 01, 2011 10:53 pm

Isn't that just a DI with a trimmer pot?

http://www.unitedmusicians.info
Contributor
Since: Nov 11, 2007


Jun 02, 2011 08:42 am

Well...the marketing doesn't lead me to believe so but eh...Monster sells directional bass guitar cables too so maybe Reamp is similar and I'm being made a fool of. Here's a link that should work:

www.reamp.com/faq.html

Administrator
Since: Apr 03, 2002


Jun 02, 2011 08:46 am

Directional bass guitar cables? Sounds like something our old friend "walters" would be selling.

www.TheLondonProject.ca
Member
Since: Feb 07, 2005


Jun 02, 2011 11:33 am

off topic

Hey dB, couldn't understand why the photos wouldn't show up and the links are broken??


Administrator
Since: Apr 03, 2002


Jun 02, 2011 11:39 am

That is kinda weird, not sure, they may be preventing bandwidth leaching in web root config files or something.

http://www.unitedmusicians.info
Contributor
Since: Nov 11, 2007


Jun 02, 2011 08:00 pm

Hey Rob, here's the problem I had:

1.) Record guitar via API 312 DI that has 470k load. I said that, but I don't know what it means.
2.) I connected an output on my recording interface (+4 dB line level) to a few different amps. It sounded like muddy mid range poo. No low end definition, all the high end was terrible, and the mids were a blurry mess
3.) I plugged the guitar directly into the amp, and it suddenly sounds amazing (H&K Triamp...love it)

I've been told that a re-amp device will match impedance to make the guitar tone arrive at the amp correctly, and remove that tone-suck factor. I used a Reamp v2 last weekend on the bass guitar with what I thought was good results, but I didn't fuss with it too much...I was after the DI bass tone and just sent some bass into the room to make the band happy. Definitely wasn't the dominant bass tone in the mix, so it could have sucked for all I know.

But I really do want to fix that problem so I can re-amp my edited guitar takes so's to make it sound like I'm a good player...bwahaha.

If it changes impedance, maybe it doesn't reamp so much as it preps the signal fro reamping...

The Czar of BS
Member
Since: Dec 31, 2007


Jun 02, 2011 09:01 pm

In reading their description on the Re-Amp. They seem to be using a really good transformer in them. Such as a Jensen. As opposed to some cheap run of the mill one.

How are you using your API?

It almost sounds as if the sync is off to have that much trouble with it. API had a good rep. And I'm surprised that the whole tone is thrown off by it. Maybe check the Mic/line switch? I'm not sure as to why it's giving you so much trouble.

As for the ohm load, 500 to 10k is typical for a mic pre. As to why it's so high for the analog side is strange? I can't find the the specs for the digital side of it. So, maybe that is the digital input resistance? I have to look that up some more.

http://www.unitedmusicians.info
Contributor
Since: Nov 11, 2007


Jun 02, 2011 09:09 pm

Well the guitar is coming in through the API, and the API is connected via SPDIF to my Digi 002 (modded to remove power supply noise, if that's a concern), and then out one of the line outs from the Digi 002 connecting to the input of the H&K via 1/4" unbalanced.

People all over the net have had the same experience that I've had, and they claim one of these re-amps fixes the problem. I wish I'd spent more time with it to be able to tell you for sure whether it even helped or not. I borrowed it and it's since been returned to the owner.

The Czar of BS
Member
Since: Dec 31, 2007


Jun 02, 2011 10:13 pm

Hummm. Odd that a DI box would clean that up being that your digital through most of your chain. Unless........... There is an issue with the API's unbalanced input. And by running it through a balancing transformer, and brings it into the XLR at that point. It's a possibility.

Hold 'Em Czar
Member
Since: Dec 30, 2004


Jun 03, 2011 02:39 am

i jus gotta say....y'all just blew my mind.....man i gotta get back in this stuff....it calls to me!

THANKS!

http://www.unitedmusicians.info
Contributor
Since: Nov 11, 2007


Jun 03, 2011 01:53 pm

From the Reamp FAQ:

[quote]
Question - Some people say I can use a passive direct box in reverse for reamping. Is this true?

Answer - – No. This would not work because of the large level differences between a microphone level signal and a line level signal. On the direct box the instrument input is designed for instrument level signals (-20dbm) and the microphone out is designed to give a microphone level signal (-60dbm typical) using a direct box in reverse would put a +4dbm signal into a –60dbm output and would cause extreme signal distortion before you even plugged into the amp.
[/quote]

Does that make sense Rob, or are you still not sold?

WYD...my mind is blown too!!! haha I don't get it...just want a good reamp...Flying Spaghetti Monster forbid I actually practice playing instruments.

The Czar of BS
Member
Since: Dec 31, 2007


Jun 03, 2011 10:27 pm

The statement that you have posted here makes total sense, And is absolutely true. Transformers are wired between the primary and secondary sides to a fixed ratio. And since we are dealing with low voltage signals with varying frequencies, it will only give a true signal in one direction.

I now understand what they are trying to achieve with their box. The primary side of the transformer has less turnings then the secondary side. Raising the voltage, but lowering the current. And keeping phase correction with a few caps and resistors. Not ideal, but not wrong either.

Building a DIY box for yourself for under a $100 probably can not be done. As the transformer that is needed is a specialty item. And will not be cheap. And unless you use the some one that Reamp uses, your going to have to preform a ton of measurements to find out how your transformer is effecting the signal. And then building the filters to correct the signal back.

I'm still very surprised that your API is in need of a higher signal. And if this is the case.......... Have you tried running out of the Pre amp out of your amp? It's after the pre, and is a line level signal. Granted that it doesn't make much sense to come out of one preamp to another. But, correct me if I'm wrong. But, I think you're mostly using the API as your digital converter right?

http://www.unitedmusicians.info
Contributor
Since: Nov 11, 2007


Jun 04, 2011 10:49 am

Cool! If it makes sense to you, then I'm convinced it makes sense, hah. Too bad on the lack of DIYable solutions. I've seen a couple online, but none were received with a tidal wave of praise as I'd expect them to be if they were really great.

The API a2d has two 312 preamps that feed the AD section, and the AD section only processes the two 312 pre-amps. Since there's no output on the a2d, I wouldn't be able to record a guitar track, edit it in my DAW, and then send it back out to my guitar amp using the API alone. I use my Digi 002 outputs as the out that feeds my amp because it's my only option. But the DA conversion on those is supposed to be pretty dang good, after the BLaudio sig series mod. I emailed BLaudio when I experienced this problem the first time and they told me to get a re-amp box to fix the problem, as the problem was with impedance. Very confident in their mods, they are.

I think I'll go ahead and pick up the Radial prormp when I can afford to. The reamp v2 design was sold to Radial engineering and my assumption is that the prormp is basically the same thing. Too bad the PROrmp doesn't have that cool XLR/1/4" trs combo input...

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