tube pre amp questions

**mr audio guy** · 10-16-2006, 03:55 AM

Ive been recording using an amek 9098i pre and an ssl pre and never had problems. I just got a job at a new studio and all there pre's are tubes. I am using an Avalon right now. here is where i am confused, and i am not quite sure how to word this:
First i should let you know that am recording vocals. I understand that when recording directly into protools you should get the signal as hot as possible w/o it clipping. however, the pre amp distorts at a really low level. when the VU meter hits zero on the amp, the level on protools is just too low. if i bump it up past zero it starts distorting. It seems to distort the mids (400-700 hrtz) the most. the only way to gte proper level in protools is too slam the needle all the way to the left (which sounds terrible obviously.)
The way i have been working around it is to turn the input up so it hits just below zero on the pre and then turn up the output, but this still doesnt sounds right. i have a great avalon mic pre but i cant get it to sound as good as i know it can and its driving me nuts. i also tried going into the avalong and then into a compressor just to use the output gain (no compression) but it added too much noise. I have had similar problems with a pendulum mic pre also. im not sure if its b/c the are both tubes and need to be used differntly or what

Anyone that can help is the ****.

**mr audio guy** · 10-16-2006, 03:58 AM

one more question while im at it.

I got a 1/4 in cable and a TT cable and i need to cut em open and make a tt to 1/4 inch cable. The 1/4 in has red and white and the sheild, the tt has red, black, blue, white and sheild. what wires do i solder together?

**jmail** · 10-16-2006, 09:12 AM

What kind of mic? If you set the level to what would be consider "normal" positions on the dials, is the meter level *way* low? Like, perhaps the phantom power needs to be turned on for a condensor mic? Or, perhaps, the voltage is set incorrectly for the mic (if you have that option)?

**mr audio guy** · 10-16-2006, 12:22 PM

the mic is a sony 9000. no phantom power from the pre amp but it has its own power supply. but i also used a Blue kiwi and i turned on phantom power but still had the problem.
the signal only got to about half way up the volume meter on protoo;s before it distorts. even if i set it so it hits zero on the pre amp, i gotta turn the out put all the way up. it is actually impossible to make the signal clip.

**jmail** · 10-16-2006, 01:03 PM

What kind of interface are you using? M-Audio? Digi-Design? Does it have a +4/-10 setting for balanced & unbalanced? Some interfaces have high-headroom built into their +4 settings, so they don't overload. You could always try the -10 setting if you're on the +4...

**mr audio guy** · 10-16-2006, 11:50 PM

im using pro tools HD with 2 192 interfaces

**af-87PRS** · 10-17-2006, 06:06 AM

you've got some real nice equipment there and it's a shame it isn't functioning properly for you, it almost sounds like the ohms settings are mismatched. I use a tube mic in my studio, and if the ohms don't match the mic-pre it causes me alot of distorion and recording problems.

**mr audio guy** · 10-17-2006, 10:42 PM

how can i make sure the ohms are matched on the mic and pre?

i also just used a blue kiwi and am having the same prob, although it doesnt seem to be quite as bad

**af-87PRS** · 10-18-2006, 04:51 AM

You would have to check in the tech sheet, find out the impedence of your microphone, most large diaphram condensers are 150-200ohms (I think) and then check to see if your mic-pre can be set to match, you may already know this stuff??? seems ya would with that expensive of gear, hope this helps a little.

**mr audio guy** · 10-18-2006, 01:09 PM

im gonna check the ohms and see if i can get them to match. i feel kinda dumb cuz i just realized i havnt even switched mic cables to see if thats the prob. im about to do that. hopefully it is something simple like that cable. thanks for your help. i appriciate everyones input

**af-passerby3141** · 10-18-2006, 02:06 PM

Sounds like an ohm issue to me as well. I would add, that I have seen ohm ratings on condenser mics as low a 50, and as high 1k. I'm no expert, but if I remember correctly it's best to have the input impedance on the pre set higher than the output impedance on the mic.

**af-87PRS** · 10-19-2006, 04:59 AM

that's also a very good thought about the cabling...mr audio guy, welcome to the audio forums (little late), I hope you solve this problem, and please keep us all informed as to the outcome, its always interesting. passerby is right about the ohms and differences, being a tube pre it seems it would have a lower ohms setting and right on ...my tube mic is 150, I set my pre to 200 and it works pretty good. What model Avalon are you using? I've always wanted to try one of those babies out.

**mr audio guy** · 10-19-2006, 02:58 PM

The avalon is vt 737 sp.
I havnt checked the cables yet b/c i havnt been back to work. but if that doesnt work and i need to check the ohms.... well how to i do that. if i take the pre off the rack is there something on the back i can adjust? and if i use a bunch of different mics with different ohms than i will have to be able to change the ohm setting on the pre whenever i switch mics, right?

**af-passerby3141** · 10-19-2006, 05:51 PM

I just did a quick search on the Avalon you mentioned, which I hate to do because I want one but could never justify the expense.

But in the spirit of team play, I'm over it!

I noticed it has balanced line ins, and the mic and line inputs are on the back. Since you mentioned it was in a rack, I assume you are plugging your mic into some kind of patch-bay. Make sure you are plugging into the correct input! If you plug a mic into a line input, it could also be the cause for your troubles.

**mr audio guy** · 10-19-2006, 06:57 PM

the guy has his studio wired kinda weird. the mic plugs into the mic panel then goes straight to the mic pre, no patch bay. the output of the avalon is on the patch bay, so i just go from the output into protools line1. im about to take the pre out of the rack and double check all the connections, the ohms and all that. this problem is gonna get fixed soon.