Profex II hiss problem

John McClung · Post by **John McClung** » 2 Jul 2004 2:43 pm

Is this common, or is there a cure?:

I revamped my signal chain following Brad Sarno's generous expert advice, steel > Matchbox>vol pdl>tube screamer>compressor>Profex II>Webb amp.
Works fine, except with Profex after the vol pedal, I get unacceptable loud electronic hiss. Can turn down the sensitivity knob on my Webb amp, but of course that lowers the volume to an unacceptable point.

I would like the delays/reverbs after the vol pedal to allow natural decay, but so far my only idea is to use the Profex before the vol pdl as a pre-amp only, and put a separate delay gizmo after the vol pedal (long as it doesn't add terrible noise).

Thanks for your help; I know effects chains have been discussed, but my quick search didn't turn up answers; sorry if this is redundant and already taken care of in the Forum archives!

------------------
Mullen D-12/MSA D-12/Sho-Bud Pro 1 S-12/Melobar/Webb/Profex II

John Daugherty · Post by **John Daugherty** » 2 Jul 2004 4:00 pm

John, I had the same problem. Mike Brown talked with me about the problem. He said It was caused by "double preamping". Since the profex is a preamp and I was feeding it into the guitar input on my Nasville 400 I was amplifying the profex noise with the guitar preamp.
His solution was connect the output of the profex to the pwr-amp-in on my amp. I did not care for this sound at all.
Sad to say, although the profex is a wonderful piece of equipment, I was not satisfied with the hiss (white noise) that it generated.
After getting some input on this subject right here on the forum, I bought another effects unit which is virtually noise free.
I cannot say that all profexIIs have this problem. I know mine did.

Tom Mortensen · Post by **Tom Mortensen** » 2 Jul 2004 5:09 pm

I seldom use my Profex II with an amplifier but when I do I turn the output knob on the back of the Profex way down. Maybe to 9 or 10 o'clock perhaps less.
Whatever point that it seems like I'm not double pre-amping.

Ken Fox · Post by **Ken Fox** » 2 Jul 2004 5:16 pm

Too many preamp stages ahead of the Profex, you are amplify a lot of noise. It is a preamp and you are sending it a preamped signal! Here is something to try:

Steel guitar output > Profex 2 input (no need for a Match Box, the Profex has the basic same opamp at its input and will provide a nice match to the pickup)

Each patch would need to be written with the "effects loop" (FX)inserted at the front of the chain. Set the "send level" at 100, the "direct level" at 0, the "return level" at 100 and the "Summed output" at off. Patch other units like this:

Profex 2 "effects out" jack > TubeScreamer > Compressor > Volume pedal > Profex 2 "effects input" jack.

John McClung · Post by **John McClung** » 5 Jul 2004 2:05 pm

Thanks for all the great tips, gentlemen, I'll try turning down the output first (easiest!). Not sure if I'll get enough signal to the amp, I can't turn my input up past 9:00 o'clock without splatty distortion. If not, next I'll try your tip, Ken, sounds complicated, but if it works I'll figger it out, I reckon.

Thanks so much for sharing your knowledge!

Hope you all had a happy Independence Day.

Dave Ristrim · Post by **Dave Ristrim** » 7 Jul 2004 6:46 am

I have used a ProFexII in my rack for years. Steel-Vol Ped-Mesa Pre-(Profex in effects loop)-pwr amp-spkrs. I had the Profex input down around 1.25, the output about 12 o'clock and fooled around with the settings in the patches. Whatever I did, it worked. I have cut records with it and have kept picky engineers happy. Of course, I am using something different now. Why??
Dave Ristrim

John McClung · Post by **John McClung** » 7 Jul 2004 1:45 pm

OK, Dave, I'll bite: why? and what?

Dave Ristrim · Post by **Dave Ristrim** » 8 Jul 2004 4:38 am

John, I am one of those let's-try-something-new guys. Lately I have been going back to the basics. I'll use an old Twin with stomp boxes, or just go direct with a Pod. My rack was 20 spaces in the early 90's, shrunk to 7 spaces, then grew to 9 recently. I am in the middle of working in a Webb amp, and also love the Vetta head. Let's just say I am in transition.
The ProFex II has been good to me. Lot's of internal tweaking and I came up with nice patches. The gain structure seemed a little wierd to me. The mix and final output of each stage of the patch is critical. I ended up starting from scratch many times, totally ignoring any Newman, or factory presets. I will try and dig the unit out and see what I did and post patches when I have time.
It seems that just about everything works for me, given enough tweak time. I think I suffer from option anxiety right now though. Not good.

Dave Ristrim

Jim Florence · Post by **Jim Florence** » 8 Jul 2004 11:48 am

Kind of strange that nobody said to patch the profex into the pre-EQ patch. I thought that was what Peavey recommended. That's where I put mine and it sounds fine.

Tony Orth · Post by **Tony Orth** » 9 Jul 2004 9:14 am

Just an observation. When running my ProfexII through my Evans amp, I do get quite a lot of hiss at stage volume. However, through my Nashville 400, I can hardly detect the hiss at stage volume. It doesn't seem to make a great deal of difference whether I use the pre EQ patch or the regular input on the Nashville 400.

Is it that the Peavey products just work better with each other. I don't know????
Can anyone answer this?

TOny

Charlie Hall · Post by **Charlie Hall** » 11 Apr 2013 7:14 am

Ken Fox wrote:Too many preamp stages ahead of the Profex, you are amplify a lot of noise. It is a preamp and you are sending it a preamped signal! Here is something to try:

Steel guitar output > Profex 2 input (no need for a Match Box, the Profex has the basic same opamp at its input and will provide a nice match to the pickup)

Each patch would need to be written with the "effects loop" (FX)inserted at the front of the chain. Set the "send level" at 100, the "direct level" at 0, the "return level" at 100 and the "Summed output" at off. Patch other units like this:

Profex 2 "effects out" jack > TubeScreamer > Compressor > Volume pedal > Profex 2 "effects input" ja

Hi Ken,,,,Would you PLEASE give me an idea that I could try ???? I too also get a hiss noise in my NASHVILLE 400 when I put my PRO-FEX 11 thru the front of the amp....I know that I can plug into the back of the amp. but I don't like the sound at all that way....Is there anything that I can do do have LESS hiss and still go thru the front of my amp... If I turn the out put down on the back of the PRO-FEX,,,,will that help????
Also,,,do you still sell the op amp. upgrade for the PRO-FEX ???? Would that help tone down the hiss and what is the cost of the upgrade ?????
Can a DUMMY like me install the upgrade ????

THANK YOU
Charlie Hall