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Tube pre-amp hiss/buzz!! Help please. Drum Machines & Samplers
Old 4th September 2011
  #1
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Tube pre-amp hiss/buzz!! Help please.

Been havin Tube preamp probs Lately.My main thing is gettin rid of all that dam hiss! I mean a lil bit is coe but after i Eq and compress it really stands out.Tried noise reduction plugs and didnt like the sound they gave me and i figure i shouldnt have to use those.Then i figured the tube knob was producing it but if i turn that down with the signal even hit the tube? Im tryna get as much tube sound as possible without all the hiss.Another stereo tube unit ive been using with my MPC 1000 for trackin has a buzz noise when the tube gain is up! does that mean i have to replace the tube??? Any help would be great and even better if someone uses tubes in there recording setup as well.

P.S. - Im using a summit audio for my vocals and a bellari dual tube with my MPC 1000.
Old 4th September 2011
  #2
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Always have spare tubes on hand. As I'm not set up for testing tubes, I use Kevin Deal at Upscale Audio, or the Manley folks. Jim McShane also has a great reputation among hifiers. (And if you want to know why you should pay someone else to test the tubes you buy, look at Upscale's page on tube testing.)

You can also get deals from people who don't test - after all, testing a tube never makes a tube better, and there are lots of great tubes out there. It's a matter of deciding whether to pay for the almost sure thing, or take a chance and maybe get a great deal. Note that there's lots of tube fraud going on - crummy cheap tubes and ancient pulls cleaned up, re-silk-screened and put in packaging that duplicates the new-old-stock boxes.

It's a lot like the old jewelry adage: if you don't know jewelry, know your jeweler.

WW
Old 5th September 2011
  #3
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Jimsi's Avatar
 

Hi, i have 3 tube preamps and never bought a NOS preamp tube. I check Ebay feedback from tube sellers and buy used tested. I've found a 20%-25% failure rate and all I bought from refunded for the bad tube which in most cases were microphonic, but i can say the vintage tubes I buy are less than $10 shipped (except telefunken) each and sound far better than new tubes...

i bought 3 Telefunkens which were flawless for $73 shipped, they are my favorite so always have a spare or two tubes, JJ Tesla new stock they say arnt bad...oh, i use them in tube amps and preamps...
Old 5th September 2011
  #4
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possibility

Just throwin this out there as a possibility but have you tried grounding your preamps or using some sort of power conditioner??
Old 5th September 2011
  #5
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You've probably already tried this, but usually with these noisy, cheap tube preamps there are 2 gain stages-- or rather, one "tube" knob and one "output" knob. Crank up the less noisy one. On my gnarly little PreSonus TubePre, the sweet spot is with the Drive cranked up to 3 o clock, and the Gain way back at 9 o clock. I can't bring myself to use the pad. I've also heard that switching out the tube lowers the noise floor significantly but its never bothered me all that much, maybe I just got a lucky one. A better, less noisy tube might make all the difference in your case though.

More importantly, +1 on using a **** preamp for your samples. Gives them life and character like no other.
Old 5th September 2011
  #6
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Analok's Avatar
NE 5532 IC upgrade??

If you're using a Bellari 220 I think there's an 8 pin IC on the main board that can be upgraded to an ultra low noise device - the NE 5532. That might help. Then again, tubes can present their own noises too, like pops & microphonics as well as hiss...even NOS JAN grades. Take what's been stated here by other members as guided advice - buy from reputable dealers & they'll work with you if you run into noise issues. Telefunkens DO reap high premiums for a reason - high quality!! Sylvanias typically get microphonic, GEs and RCAs are usually of high grade but vary upon their vintages/construction materials (I'll not go into details over "D" vs. "Square" vs. "Halo" getters - that's another chapter within another volume and generally for 'cork sniffers' anyway).

Last edited by Analok; 5th September 2011 at 04:13 AM.. Reason: spelling
Old 5th September 2011
  #7
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guveneur's Avatar
 

Like stated above, try switching outlets or to a clean source. Also, I know this may be dumb to say, but did you try switching out mic cables and the mic to make sure that isn't the source of your hiss?
Old 5th September 2011
  #8
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Hi
A Valve mic pre will always be at least a little more noisy (hiss) than a solid state unit it is down to the basic physics of the parts used. If it has a hum or buzz then it needs to see a doctor.
Practically all op amps made in the last 40 years will be quieter than a valve when used in any 'sensible' circuit so swapping to a NE5532 is unlikely to improve much on the hiss front.
The technique to minimise the hiss is usually to get as much gain as you can as 'soon' as you can (the first stage of the mic amp) and do not use pads unless you really have to, although if you are getting hiss and you need a pad you have something seriously wrong.
A mic cable CANNOT produce hiss but types with poor shielding MAY allow high frequency 'rubbish' from switch mode supplies or elsewhere to get in which may sound like 'hiss'.
It may be worth reviewing your actual technique as adding EQ and compression both have a tendency to accentuate any hiss or other noises. If you consider 'old fashioned' tape recording, the deal was to overemphasise HF during record so that on playback you can 'cut' the HF a little more so reducing hiss from the recording machine. Dolby did this 'dynamically' altering the frequency response related to it's level.
You should of course check the noise spec with the manufacturers published values. Put a 'termination' on the input and measure the resultant noise.
Matt S
Old 5th September 2011
  #9
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Analok's Avatar
Excellent info!!

All valuable data & a learning session for myself as well. Thanks, Matt!!
Old 5th September 2011
  #10
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Thx for the responses people.Imma dig deeper and figure this ish out.
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