PreSonus mods

[Bino_5150]

I recently purchased a Presonus bluetube dp... Now, I know there was places like black lion that offered tweaks and mods for this pre... It was supposed to be a night and day difference as far as the sound goes. Black lion no longer does this, however...

Gear modding is a very common thing, and I can't be the only one here ripping the cases off of my equipment in search of better sound...

So, does anyone know of anywhere that does, or any instructions for, modding this preamp?

Also, has anyone had any luck changing the tube? I know that it was mentioned that there was another tube that could be swapped out for the stock one, and it was supposed to be a hellova upgrade.

btw, once the pre arrives, my signal chain will look like this:

AKGC3000B mic> BlueTube DP pre> Behringer MX2004 mixer> BBE Maxcom> DAW (Adobe Audition) via Echo Mia MIDI 24/96

[Bino_5150]

man, anybody? Does anyone here have modded gear? I figured someone would have some information...

[Bino_5150]

Nobody has swapped the tube out or anything? Nobody had there unit modded by Black Lion? C'mon now... someone has to know something...

[terry]

Try this http://sound-on-sound2.infopop.net/2/OpenTopic?a=tpc&s=215094572&f=884099644&m=456101062&p=1&x_print=Y

[Bino_5150]

Hey thanks man, I appreciate the post. There is some good info in that thread.

I purchased a Tung Sol 12AX7 tube to replace the tube that came in it.

I am also going to purchase a Groove Tubes 12AX7M and see which one I like better.

Does anyone know the details of exactly what Black Lion actually did to these pre's?

I remember them recommending that you change the tube for better sound, but that wasn't what their mod was...

From what I've gathered, the BTDP isn't a bad pre by any standard. The only complaints that I've heard really are that the gain is "weak", and the tube is crap, and it's "cheap" along with some other minor things; No one really complains too much about the sound quality besides the tube.

This is what the link up there said:
1)Change the tube... this one's not for the faint of heart, but the stock 12AX7 in it is horrendous.
2)Replace the driver OPAMP
3)Change the drive potentiometers to halve the amount of drive.
4)Change some of the resistors driving the tube to get a slightly higher plate voltage

Where's the PreSonus guy at? Does anyone have anything to say about this? Those instructions are vague to say the least...

For those interested, I will document my experiment so others will know just how good this box can be...

[terry]

Bino_5150

Not really sure if any presonus rep. is going to support a mod to there product. You know the whole liability thing. Id be very interested in how it sounds when you get done modding it. My current project involves making a electric violin using guitar pickups and as well a bridge pickup to. I know a few forums that have a mod sections in them. Here you go might want to post the same question.

http://studio-central.com/phpbb/index.php?sid=5b3545ba72ce2fccb844f2c36d825442

http://www.presonus.com/forums/forumdisplay.php?f=12

thats about it. Id just google for forums that do mods

[Bino_5150]

well, as far as the PreSonus reps not wanting to support mods, there is a whole page in the manual like this:

"We expect some owners of the BLUETUBE DP will try different tubes to investigate the various performance possibilities they might provide." It then goes on to tell you how to swap the tube, so yeah, they know we are modding their gear. I mean, we paid for it, what complaint could they have?

After plugging it in for the first time, I see why they put that in there, too...

I plugged it in, and let the tube warm up for a little over an hour before I ever messed with it.

In solid state mode, it is crystal clear and very dynamic, with literally no noise at all. I would call that a top notch pre, I don't care what the critics say. I found gain very easily without having to crank it too hard, and it really didn't color the vocals much at all; nothing noticeable, which is a very good thing. It has a very natural sound, spacious and bright, and compliments my mic well. I have used much more expensive pre's that did not sound anywhere near this good... I began to realize that yeah, this is a very good preamp.

And then I turned the tube on...

I must admit, I see why people complain now, and I was not impressed at all. That isn't what I had in mind for a mic pre... guitar maybe, but definatley not on a good mic in a high end recording setup.

The tube was a bit noisier than I would have liked, and it sounds horrible, even on low drive. At 15-20% drive and nowhere even close to clipping, I get distortion. The louder I get, the more distorted it becomes, to the point that when my vocals are at a decent level, the effect is not acceptable.

There is no "tube harmonics", no "Sweet, soft, silky, phat, warmth". It sounds like sandpaper and bug zappers.

Even on a quite signal, the tube sounds very harsh and aggressive, with this very high pitched, rough-grainy texture that I really can't stand, and the super clear mic of mine now sounds muddy, like a radio shack karaoke mic.

From the time you turn the tube on, on the very first click of the dial, you begin to hear the hum, and the noise becomes very clear on the VU meters from the mixer to the DAW .

Maybe the tube has to be broke in? Or is it really as bad as they say?

Judging from the performance in solid state mode, which I am more than satisfied with, I am guessing that the tube is the weak spot in this pre. Most people that I have talked to that have experience warned me of this, and told me once I change the tube, I'll be fine. We'll have to wait and see... the tube should be here in a couple of days.

has anyone else here experienced these results?

For now anyway, I will continue to use it with the tube off, as it performs well that way.

I'll keep posting for those interested.

For the record, let me say this in defense of the BTDP: I purchased a very good $200 pre, and if I can get the sound I want out of it by swapping in a $14 tube, then I am totally satisfied, and got my moneys worth and then some...

My thing is this: tubes are cheap, even the best ones. If PreSonus knows everyone complains about this, why not use a better tube to start with?

[terry]

Bino_5150

I stand corrected. In fact if you go over to the presonus forum and pm westley (I think i got the spelling right) and ask him about it I'm sure he will help as much as possible. But just the same I guess its cool they would put something like that in their manual. Personally I don't own one. But I like to know how it turns out after you upgrade it since ill be looking for something like that for my violin.

[Bino_5150]

I would highly recommend it for the violin in solid state mode. It will give you a nice clear sound, very crisp and clean.

I'll let you know about the tube as soon as I get it swapped out. I'm trying to find that "round warmth" I read about in the manual lol!

If you ever decide to go heavy metal violin, crank the stock tube up!

[terry]

Bino_5150

good suggestion!

[Bino_5150]

for what its worth, I am experiencing a noise floor between -87 and -84dBu at my DAW on input monitoring. I really have no complaints about that.

I'm liking it... now, off to do some more research on upgrades...

Let me know how the violin thing turns out!

[terry]

Bino_5150

Ill post some photos when it done.

[Bino_5150]

so um... where exactly is the PreSonus guy? Doesn't come here much or what?

Hopefully the new tube will be a bit smoother and quieter, as this crunchy sound is not cool at all...

[terry]

Bino_5150

Dude You got to go over to their forum and pm him. Here is the link. look for Westly.

http://www.presonus.com/forums/index.php

[Bino_5150]

well, heres an update...

I thought I got my tube to calm down and act half-way decent... figured maybe it had to break in or something... now I think its just broke.

I do believe that the tube is not functioning, or at least the tube drive isn't. There is no change in sound now, even when I crank the drive full blast. Maybe my unit was just defective or something?

My new tube came in the mail today, so hopefully either tonight or tomorrow I will install it and see what difference that makes.

I must admit that I am a bit excited to see what this new tube will do.

As far as other actual mods for this pre, I'm not having much luck at all... if anyone has any info, please share.

[passerby3141]

While I don't knock you for looking into it, I think it's generally better to spend more money up front than modding stuff. The exception being, pickups and tubes, IMHO. But, I had a Blue Tube for a while, I swapped the tube out constantly, one day it just shorted out on me. I fully blame myself, and I offer my anecdote as a cautionary tale.

[dcwave]

Most of the tube stuff marketed at the project studio market tends to just have a $1 chinese tube in one stage of a design that is mostly cheap opamp circuitry, and typically run at around 50 plate volts, a "starved plate". This design offers no dynamics, no headroom, no bandwidth. The best you can hope for is a decent guitar/bass DI box or use it as a FX type pre. In traditional designs most of the time the voltage on the plates of a 12ax7a is at least 150 volts, and often 300 volts or higher. Generally speaking, higher voltages, within the tube's operating range, mean higher dynamic range and better sound - clean even.

A different tube will change the sound however; You would think that since the tube is operating at near failure voltages it really wouldn't matter much but it does. I have an old Art MP I modded a long time ago with a Groove Tube and a different op amp and it gave it a bit more headroom and smoothed out the sound. It gets used as a DI for overdriving bass guitar a bit, but its still hard to get sitting in the mix because its just "blurry".

Oh and if you do get it sounding half-way decent, bypass the Berry mixer and send it direct to the mia - no sense in adding more cheap circuitry into the signal.

[Bino_5150]

well, actually, I was pretty impressed with the solid state performance. I like the presence that it gives. I haven't quite figured it out, but there is just something about the combination of my AKG and this pre that has a very distinct sound that I LOVE. My other mics dont, and other pres dont set off my AGK... just something about this combo I guess. They should X the tube and just do a good solid state amp out of this unit...

I came to grips that my mic will never cooperate with a tube and this pre, but its silk in solid state mode, so thats what it is...

The new tube did make a difference. I don't know if I just had a defective stock tube, or if they really put that trash in their electronics... I wouldn't expect that from presonus, but hey, wouldnt be the first time...

I also use it for instruments, phono, keyboard, whatever... and the tube only comes on as an effect on certain keyboard patches.

My mixer has been swapped out for a Xenyx; I'm quite pleased with the results. If you hear my final product, you can see why I find no need to spend a 4 digit number on a mixer.

[tha]-[acksaw]

i just got the Blue Tube a few days ago and have been playing with it since. Its so funny to read all of this cause I have been telling myself for three days that I'm just not setting this thing up right cause the tube stage sounds like ****. Great Solid State just as you said. I was just wondering what Tube you swaped it out for and where you got it... and I guess anything else you found out along the way cause I seem to need to do the same thing. Also is there any way of listening to any of the vocals you recorded with the Pre and Mic you have. I'm a sound nut and would love to hear anything. Thanks for posting this thread. Sure made me feel lots better about myself after finding I'm not the only one having problems.

[Bino_5150]

I replaced the tube with a Tung-Sol tube. I think the tube is not the weak point, but as it was stated, the hardware driving the tube is not up to par with the task. The tube was a major difference, but I still do not feel it is worthy of vocal use. It works ok on instruments, but thats about it. Maybe it's the characteristics of my mic also, but the tube makes vocals sound very muddy, with the bottom end quick to distort, and the top end sounds like theres a towel over the speaker. And the tube is NOISY. The clarity of my micis reduced to about a $13 Radio Shack mic. It dulls all of the life out of my recordings. The new tube is a bit smoother, where as the old tube crunched like chewing on gravel.

There was a couple of companies that modified this pre, and it was supposed to be amazing night-and-day results, however, I guess the circuit they were using was not stable, and they are no longer offering the mod, or any information on it.

I will post up some of the vocals we just recorded if I get a chance later this evening.