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Topic: Seven Session 400 questions. |
Travis Bernhardt
From:
Vancouver, British Columbia, Canada
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Posted 19 Apr 2004 10:01 am |
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I just bought a Session 400 amplifier. Its serial number starts "8A" so I gather it's a 1978 model (yes, no?). The speaker has a cobweb image on the back, so I guess it's a "Black Widow." Questions:
1. The power switch can be flipped left or right to turn on the amp, what's the difference?
2. Even with nothing plugged in, there's a hissing noise. When playing, the signal/noise ratio is fine and you can't hear the hissing, but if it's fixable, how does one fix it?
3. The knobs are a little scratchy, how does one fix this?
4. When the amp turns on there's a sort of deep thuddy popping noise--normal?
5. What the heck is the "Shift" knob doing?
6. What is the "Sensitivity" knob doing?
7. The EQ knobs--where's perfectly flat?
Umm, and that's all I've got for now. I have to say, compared to my little 15w tube amp with a ten inch speaker... well, now I know what I've been missing. I love the sound, and the power is amazing. The low notes practically leap out of the amp, where before they kind of whimpered out quietly. What a difference.
-Travis |
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Larry Bell
From:
Englewood, Florida
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Posted 19 Apr 2004 11:14 am
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1. The power switch can be flipped left or right to turn on the amp, what's the difference?
It reverses the polarity. Sometimes it will cure a ground loop. Sometimes not.
2. Even with nothing plugged in, there's a hissing noise. When playing, the signal/noise ratio is fine and you can't hear the hissing, but if it's fixable, how does one fix it?
All amps I've ever had do that at gig volume.
Replacing the filter caps might help.
3. The knobs are a little scratchy, how does one fix this?
Clean them yourself or send it back to Peavey. They'll turn it around in a week or so.
4. When the amp turns on there's a sort of deep thuddy popping noise--normal?
Nope. That could be a capacitor too.
5. What the heck is the "Shift" knob doing?
It's a sweepable midrange. It works in concert with the MID control to boost or cut frequencies centered wherever you set the SHIFT control.
6. What is the "Sensitivity" knob doing?
Master Volume or PostGain
7. The EQ knobs--where's perfectly flat?
I start with everything at 12 o'clock and usually end up fattening up the bottom end, tweaking the mids to the room, and adding just a tad (3 or so) of HIGH and PRESENCE.
It's a great amp. Some of the noises you mention could be cured by having Peavey go over it. Give Mike Brown a call and he'll fix you up.
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Larry Bell - email: larry@larrybell.org - gigs - Home Page
2003 Fessenden S/D-12 8x8, 1969 Emmons S-12 6x6, 1971 Dobro, Standel and Peavey Amps
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Mike Brown
From:
Meridian, Mississippi USA
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Posted 19 Apr 2004 11:21 am
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Hello Travis,
Thanks for the seven questions about the Session 400. Without the complete serial number, I can't tell you if it is a 1977 or 1987 model. I am assuming that it is a 1977 since the power switch moves left to right.
Answers;
1)The ON/OFF is a polarity switch as well.
2) The capacitors in the tone circuit could possibly need replacing. You might want to check the power supply caps for leakage while you are at it. Note; "Hissing" is more evident when the HIGH or PRESENCE controls are increased.
3) I highly recommend that you lube the pots with DeOxit or Peavey Funk Out lubricant/cleaner.
4)Since the model in question is a solid state model, the slight pop could be normal. Unlike tube amps, the Session powers up instantaneously. Could be normal but I recommend that a qualified technician check and repair your amp accordingly.
5 through 7) Check here; http://www.peavey.com/support/searchmanuals/results.cfm
The original operating guide is pretty good with the explanation of the operation of the control panel, so I'll let it speak for itself. Here's the link; http://www.peavey.com/support/searchmanuals/results.cfm
If you have further questions, feel free to call me here at Peavey and I'll be glad to assist you. I can be reached toll free at 1-877-732-8391. Thanks.
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Brad Sarno
From:
St. Louis, MO USA
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Posted 19 Apr 2004 11:34 am
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Great questions! I'll take a stab at it.
1 - The power switch goes two ways. In the case that you have lifted the ground or are in an evironment where there is no third prong ground, the switch controls which terminal references ground. Basically in that situation, check to see which one has less buzz and doesn't shock you when touching other devices. Basically, always use a grounded outlet and don't worry about it.
2 - The hiss could be from the age of the amp's cap's. After 26 years, the electrolytic caps could use replacing. The Session 400 is the quietest amp I've ever heard. Mine is all recapped and you can't even tell it's on unless you stick your head right in the speaker, and even then it's barely audible. I don't know how they did it, but it's amazingly quiet.
3 - Scratchy pots. Pull out the chassis. Get yourself a can of the Caig Calilube. It's made for potentiometers. Spray a tiny amount up inside each pot. There's an opening near the terminals that will let the spray get inside the pot. Turn each knob back and forth a few times to spread it around and clean off any oxidation. The pots should be good for years after that. Peavey uses real good pots in there so they rarely go bad other than getting scratchy.
4 - That's the famous Peavey "Pop". Get used to it. To eliminate it would require a bunch of extra electronics and timing crud. It's a sign of a healthy Peavey.
5 - The Shift knob works in tandem with the Midrange knob. The Shift knob chooses your midrange frequency. The Midrange knob chooses how much you cut that chosen frequency. Noon and Noon is a good starting point. It put's a nice medium dip at around 800Hz where many players like it.
6 - Sensitivity is basically a fancy word for master volume. It's the sensitivity of the power amp section. Since the Session was named for being a recording "session" amp. That ability to turn down the power amp section helps to get the amp super-quiet in the low-volume recording situation.
7 - This seems funny, but that midrange control is not like the modern types where you can boost and cut frequencies. It is a cut-only midrange control. To get the Session 400 "flat" you should set it like this:
presence - noon
treble - noon
midrange - fully clockwise
shift - fully clockwise
bass - noon
You'll notice that this is a very midrangey sound, but that's why most all steel amps have a midrange dip pre-voiced into the sound. If you put the midrange knobs a noon, that actually gives you a decent sized midrange dip that probably sounds much more musical than flat. You'll probably also want to crank the bass to about 7-10.
Brad Sarno
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John Fabian
From:
Mesquite, Texas USA * R.I.P.
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Travis Bernhardt
From:
Vancouver, British Columbia, Canada
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Posted 19 Apr 2004 4:17 pm
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Whoa... I'm almost embarassed by the speed and completeness of the answers. Thanks! I'll get to work...
-Travis |
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Terry Sneed
From:
Arkansas,
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Posted 20 Apr 2004 8:00 am
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Travis, I think you have the same amp I have.  my power switch goes both ways also. my session has always had a slight pop when the power switch is turned on, I think that must be normal. My knobs need cleaning also, just a little scratchy.
It's one heck of an amp though. the only thing I've done to it, is replace the BW speaker, and mine must be about a 77 model to. great soundin amp!
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TW Sneed
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