Which preamp to use

  • Thread starter Thread starter Vega_
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Don't get me wrong, I think the sound of the pre amps on the saffire pro 40 far surpasses the interfaces I've owned in the past. But as the others have said, I'm interested in external pre's like the MPA II because of the this certain color that I go for. And I know the sound in my head, like everyone does. And I'm always trying to achieve it, especially with acoustic guitar.

I do like having the low cut filter on the pre amp going in. Because I am not the best EQ guy in the world. And if I record an acoustic guitar and there is too much bottom end, I know how to take it out in the DAW but I also know where it sounds perfect for the acoustic and the mic I'm using to mic it. And I just record in with it doing that.

The impedance knob the other factor. That thing makes a bigger difference than I realized the first year or so I had this pre amp. Most pre amps just default at what ohm they are set to. The plate voltage as I've said is another huge thing that works with acoustic guitar and vocals that I can't emulate very well in the DAW and the pre amp does it for me.
 
For a budget I found the ART pre's like the MPA to soung great.
The downsides are that they are not so reliable: pots are sometimes noisy, the VU's often jam and are not really accurate and the lights burn easily.

But its still worth the price.

Otherwise I would suggest that you save your money to buy high quality stuff like API or Neve because they never fail at anything.

Just keep in mind that different qualities of mic pre aren't changing that much your sound... It's more the reliability and the headroom that you'll get.
 
I didn't see anyone mentioning that the MPA II is a "starved plate" tube design - there isn't enough power going to the tubes as a preamplifier. To be blunt, that tube circuit is only to add noise from those poor starving tubes. Some guys use just it without the tube stage and are happy with it.

I would suggest purchasing a nicer pre like the RNP and then if you want to use that "tube dirt," use a effect when you mix. There are plenty of free ones out there to download. You could even try going through a distortion pedal in the mix.

Disclaimer - Yes, I do own the MPA II - which I used once and then took it apart to see how it works and then farmed it for parts to build a G9 tube pre. And I do own a RNP. The closest other pre I can compare it to that I own is my John Hardy. Yes, really, the RNP is quite nice for the price - more noise, but doesn't sound sterile at all.

You know, maybe something like a Pre73 might sound good too. I have not used that though, so I really shouldn't promote it.
 
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I would be a mistake IMO to simply dismiss "starved plate" operation* as always being a cheap, non-effective design "trick". The circuit technique does have a valid history.

The famous Mullard Three-Three 3watt amplifier used an EF86 with an anode voltage of just 20V. Then, Mullard produced a range of valves for car radios that ran on 12volts! (the PA section being a single ended Germanium power transistor).

One day I hope to find the time and energy to experiment with low voltage valve circuits. They are certainly attractive to manufacturers because they overcome the safety problems on a production line (as do rat powered devices).

So, just because a product is labelled "Starved Plate" does not mean it is automatically bad in the same way that "True Bypass" is good...'Cos it ain't!

*The correct term, at least as applied to the Mullard design is "Operating under starvation conditions".

Dave.
 
ecc83 said:
I would be a mistake IMO to simply dismiss "starved plate" operation* as always being a cheap, non-effective design "trick". The circuit technique does have a valid history.
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I wouldn't call it a "non-effective design trick" if you're trying to go for that effect, but that is not how low end tube pre's are marketed. They push them as "regular" tube pres, but it's a little deceptive since they are not educating the buyers. Saying that its "cheap" is correct though. It is less expensive to make the circuit with a small power transformer, etc... to keep the price point down.

My point is to get the best sound into your DAW, and once someone uses the tube circuit on that unit you can't go back. I'd rather go in without this tube effect and have the option to use it later if it's needed.

Do you mean that "true bypass" is always better? I would almost always agree with that, but as crazy as this sounds, at least at the time, I liked the sound of my Les Paul through my Vox wah better (even though it wasn't true bypass). Hopefully today I have better ears and can hear the negative aspects of going through the wah's circuit rather than just how it smoothed out my tone.

That's really interesting to know about the Mullard. I'd like to see a car/receiver company push a 12v valve radio as being high end audio now, just because it's tube!

In any case, right now I am "operating under starvation conditions" and should get something to eat or maybe just go to bed.
 
citizen77 said:
I wouldn't call it a "non-effective design trick" if you're trying to go for that effect, but that is not how low end tube pre's are marketed. They push them as "regular" tube pres, but it's a little deceptive since they are not educating the buyers. Saying that its "cheap" is correct though. It is less expensive to make the circuit with a small power transformer, etc... to keep the price point down.

My point is to get the best sound into your DAW, and once someone uses the tube circuit on that unit you can't go back. I'd rather go in without this tube effect and have the option to use it later if it's needed.

Do you mean that "true bypass" is always better? I would almost always agree with that, but as crazy as this sounds, at least at the time, I liked the sound of my Les Paul through my Vox wah better (even though it wasn't true bypass). Hopefully today I have better ears and can hear the negative aspects of going through the wah's circuit rather than just how it smoothed out my tone.

That's really interesting to know about the Mullard. I'd like to see a car/receiver company push a 12v valve radio as being high end audio now, just because it's tube!

In any case, right now I am "operating under starvation conditions" and should get something to eat or maybe just go to bed.
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No!! "True" bypass is a nonsense. I agree using a buffer with certain very old pedal designs changes the sound but that is because the pedals were technical "bad" designs in the first place.

And you don't have to use transformers to get a decent HT voltage. If you only need a couple of watts at 300V there is a pretty simple chip+L+MOSFET circuit that can be used and will run from 12V or so. Not DIRT cheap of course but used in pedals in the £100 bracket.

Dave.
 
ecc83 said:
And you don't have to use transformers to get a decent HT voltage. If you only need a couple of watts at 300V there is a pretty simple chip+L+MOSFET circuit that can be used and will run from 12V or so. Not DIRT cheap of course but used in pedals in the £100 bracket.
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Can you use a MOSFET as a power supply line enough to fully power a tube? I wonder if that would change the tone? (yeah, i know it isn't in the signal path, but i've heard that with 500 series you should really stick with the power supply intended with since using a different companies power supply can cause undesirable changes to the tone etc.... or some guys just use all in one rack gear because the power supply is always tuned to the unit - which is what i prefer)
 
https://www.google.co.uk/search?q=U...%2F12v_hv_switching_power_supply.html;931;693

That ^, is something like the circuit I am talking about (the actual one is of course not my property to divulge).

Not sure about "tuning" since a pre amp circuit will stay predominately in classA and thus PSU drain will be constant. In any case the circuit gives excellent regulation (makes a brilliant phantom power supply!) but of course any reasonable value of series R and decoupler cap can be used if it is deemed important.

The circuit has been used in many 10s of 1000s of pedals by now and has proved virtually failure free. Indeed the valve (ECC83 Ruski) gave vastly more trouble but even that was below 0.1%. In that form it mearly supplies about 2mA at 300V but I have a project (one day!) to beef it up to supply 1X ECC83,1X EF86 and 1X ECC82. Those in turn will drive a 60W class D power stage.

Dave.
 
Gost22 said:
hello wherein the schematic?
Click to expand...

Do you mean "where abouts in the schematic is X"? If so specify "x"
If you mean you don't understand the circuit then I can't help you, it is really by the way of being a starting point for development.

Dave.
 
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