Tech Tips/Tricks/FAQ- READ THIS FIRST!

This forum is for talking about all kinds of Peavey guitar amplifiers.
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Tech Tips/Tricks/FAQ- READ THIS FIRST!

Post by Roger Crimm » Tue Nov 04, 2008 1:13 pm

I will post some of the more frequently asked guitar amplifier tech questions in this thread. If anyone has any suggestions for topics, post them or PM them to me.

You can see other general FAQs at this link:

http://www.peavey.com/support/faq/
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Guitar Speaker Comparison Chart

Post by Roger Crimm » Tue Nov 04, 2008 1:18 pm

Here is a general overview of some Peavey Guitar speakers.


Guitar Speaker Comparison Chart.pdf
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JSX FAQ

Post by Roger Crimm » Tue Nov 04, 2008 1:24 pm

I have heard that some JSX amps had problems with noise. How can I tell if my amp had the noise gate enhancement?

If you have a JSX it almost certainly has the enhancement done to the noise gate. There were only a VERY few amps out of the first production run that left the factory before the enhancement was added. The rest were put on hold and were not shipped until they had been modified. There is no way to know exactly how many amps were shipped without the modification, but it would have to be less than 40-50 units. Most of those went to endorsing artists and a few dealers who had ordered them six months before at the Winter NAMM show, and have since been modified as well. Your amp already has the enhancement.

So why then is my JSX noisy?

Because it is a high gain amplifier. There are lots of reasons why guitar amps make noise, and high gain types make more than most. If you like your channel gain cranked up, you will have some noise to deal with. You should use humbucking pickups and a well-shielded guitar if you want to use high gain settings. Your vintage, non-shielded, single-coil pickup guitar is going to exhibit a severe buzz in this situation. Noisy tubes can also commonly cause problems in high gain amplifiers. They have to be good quality and carefully chosen for this type of amplifier, especially the preamp tubes.

The change made to the noise gate has nothing to do with the amount of noise the amp makes on it’s own. The change was a capacitor added to the gate circuit so that it can reduce a little more of the high frequency hiss.

The noise gate doesn’t seem to do much unless it is turned up all the way. Why is this?

Because, it is supposed to be turned up all the way. The only reason to ever turn it down would be to prevent it from cutting off notes as they begin to decay. This will usually only happen at lower gain settings or when the amp is used with very low-output guitars. Otherwise, you should leave it at “10”.
The noise gate is not really a “gate’ per se’. Noise “reduction” may be a more accurate description. The circuit does a good job, but does not have the ability to completely eliminate noise at high gain settings. This is intentional, and not a flaw in the amp or the design.

Ok, so I got the last one, which has not been modified. What do I do?

This enhancement is a simple modification (the addition of one capacitor), but should be performed by an Authorized Peavey Service Center.

Contact us here at the factory if you need assistance @ 1-877-732-8391, toll free.


My JSX sounds kind of weak compared to other 120 watt amps. Why is this?

The most common reason for it is because the effects loop level controls are turned down. This will drastically reduce the power amp input sensitivity and volume output of the JSX or Triple XXX amps. Setting both controls to halfway, or any other diametrically opposed position (ie; opposite clock settings) will achieve “unity gain” through the system. This is optimal for signal levels, but may not be optimal for noise immunity from outboard effects. In this case you should experiment with different settings based on the particular effects device(s) you are using.
Setting either or both controls low or off will reduce the power amp input sensitivity and thus, volume.
Setting them at higher settings will actually boost output when the loop is engaged. This actually makes for a handy lead boost if you don’t use the effects loop for anything else.

Another common reason for this complaint is “scooping” the midrange. The Crunch and Ultra channels on this amp are active eq, not passive like most of us are used to. You can turn the midrange down most of the way on your typical passive eq, and it sounds pretty good for high gain metal-type tones.
The active eq on the JSX is capable of a huge amount of boost or cut, much more than any passive eq. Your guitar is mostly a midrange instrument, and your ears are tuned to mids as well. Cutting the mids completely will reduce clarity, and result in a weak and muddy sound, so don’t just automatically zero out the midrange. Make small adjustments at first.

Properly set up, the JSX is every bit as loud as any other 120 watt amplifier.
We have recently begun shipping all EL34 models with matched sets of JJ EL34 power tubes, which actually result in 5-10 Watts of extra power, in most cases…all tubes vary to some degree.

How do I use the Bias Test jacks on the back?

These jacks are used read the Bias Voltage, which can be tweaked using the Bias Adjust control located next to the power tubes. It is recommended that this adjustment be done by a technician, but if you are handy with a Volt Meter you can check the voltage yourself.

Your meter should be set to read DC Volts.

For 6L6 tubes, the factory setting is ~55VDC at the test jack.

For EL34 tubes, the factory setting is ~42.5VDC at the test jack.

Can I switch the channels Via MIDI?

No, the din connector on the JSX is not a MIDI connector, and the amp does not have MIDI capability. You will need some kind of MIDI controller with relay switching ability to accomplish this.
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Din Connector Switching For Relay Switch Devices

Post by Roger Crimm » Tue Nov 04, 2008 1:40 pm

The 7 pin DIN connector that looks like a midi connector is really just a seven conductor connector, with each pin doing a certain function when grounded. All we need is the pinout of the connector (what pin does what) to make relay switching work.
Relay switching devices typically use ¼” jacks. Some use mono jacks, and some incorporate two relays per jack using stereo jacks. Refer to the owner’s of your particular product for information concerning the jack configuration and wiring.

Here are the pin configurations of the DIN connectors on Peavey amplifiers.
On the 7 pin connector (looking from the solder side on the connector) the pins are numbered starting at top right (one o'clock position).

****************************************************************
5150 II/6505 Plus

Pin 1. +17VDC supply to pedal
Pin 2. not used
Pin 3 Ground this pin to detect the footswitch.
Pin 4 Ground
Pin 5 Activates the crunch function of the clean channel when grounded.
Pin 6 Turns the EFX loop on when grounded
Pin 7 Selects between the clean and lead channels( Lead when grounded).
******************************************************

Triple XXX/JSX/3120/Triple XXX II

Pin 1. +17VDC supply to pedal
Pin 2. not used
Pin 3. Ground this pin to detect footswitch
Pin 4. Ground/Common
Pin 5. Clean/Bypass
Pin 6. Ultra/Crunch
Pin 7. Effects
*******************************************************

Ultra Plus/Ultra 60/Ultra 120

Pin 1. Bypass/Clean LED on footswitch
Pin 2. Reverb Led
Pin 3. Ultra/Crunch LED on footswitch
Pin 4. Ground/Common
Pin 5. Clean/Bypass
Pin 6. Reverb
Pin 7. Ultra/Crunch
*******************************************************

XXL

Pin 1. Bypass/Clean
Pin 2. Reverb Led
Pin 3. Ground this pin to detect the footswitch
Pin 4. Ground/Common
Pin 5. Leds (not used)
Pin 6. Effects Loop
Pin 7. Ultra/Crunch
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Tube FAQ

Post by Roger Crimm » Fri Nov 07, 2008 3:28 pm

Tubes vary in quality and construction so much that it is impossible to predict exactly how long they will last.
Power amp tubes will have to be changed more often than preamp tubes.
My usual rule of thumb is, that if you play on a regular basis you will probably have to change your power amp tubes every year or two. If you are a professional or play every day, you will want to change them more often than that. Some pro's change them weekly or even daily, but I consider that a little extreme. If you only play the occasional weekend, you may get several years out of a good set of tubes.

The bottom line is, that you might get ten hours or ten years from a new set of tubes. The best barometer to go by is your amp. If your amp sounds weak or seems to be loosing it's punch and clarity, or if it just won't clean up as well as it should, it is probably time to change power amp tubes.
Preamp tubes can last for years, so I usually only change them if they get noisy or microphonic.


The tubes we use vary depending upon availability, sometimes they are Sovtek, sometimes Ruby or JJ. It all depends upon what we can get in quantity, at the quality and price we require.

Here is what we currently stock:

6L6- Ruby 6L6 GCM-STR
EL34- Ruby EL34BHT (available as matched quads)
EL84- JJ EL84
12AX7- JJ ECC83S/Sovtek 12AX7LPS/Electro-Harmonix 12AX7EH

6550- JJ KT88
6V6- Electro-Harmonix 6V6GT
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What Tube Does What?

Post by Roger Crimm » Fri Nov 07, 2008 3:43 pm

I get asked this one a lot, so here is the tube order on some models:

The 5150/6505 actually uses the same tubes for both channels, and just throttles back the gain for clean/crunch. If you look at the rear of the amp, the preamp tubes are on the right side.

Looking from right to left, the tubes are arranged as follows:
#1 Input gain/2nd gain stage-shared by rhythm and lead
#2 is shared by the rhythm and lead channel
#3 additional gain, mostly for the lead channel
#4- effects loop
#5 phase splitter


5150 II/6505+

If you look at the rear of the amp, the preamp tubes are again on the right side.
Looking from right to left, the tubes are arranged as follows:
#1 (far right) the rhythm channel
#2 is shared by the rhythm and lead channel (input stage)
#3 and 4- lead channel
#5 effects loop driver
#6 phase splitter


Triple XXX/JSX/3120

In terms of the circuit, the tubes are numbered V1 thru V4 starting at the end nearest the input jack. V4 is the phase splitter and is part of the power amp.

V1 is the input tube and is shared by all channels.
V2 is only used in the ultra/crunch channel
V3A is the active EQ section for the ultra/crunch only
V3B is the preamp output tube.

Clean signal path is:
V1A - EQ/Pre - V1B - (loop) V3B - Master - power amp

Ultra/Crunch signal path is:
V1A - Pre - V1B - V2 - V3A (active eq)- (loop) V3B - Master - power amp.


6505+ 112 Combo

The tubes are arranged as follows:

V1a Input gain-shared by Rhythm and Lead
V1b and V2a- Rhythm Channel
V2b, V3, V4- Lead channel
V5a- Effects Return Stage
V5b- Phase Inverter

(V1 is the tube nearest the input jack)


6505MH

V1A - main input Gain
V1B - Rhythm channel / crunch
V2 - Lead Channel gain
V3 - Lead channel gain
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Classics- 30/Delta Blues/50

Post by Roger Crimm » Fri Nov 07, 2008 3:53 pm

The Classic 30 and Delta Blues are designed to use one or two 16 ohm speakers. There is a switching system in the external speaker jack, which uses separate taps on the output transformer.
When an external speaker is connected, both speakers are now in parallel, which is an 8 ohm total load, and the amp's transformer is selected to 8 ohms.

If you want to use an 8 ohm speaker with your Classic 30/DB, you should disconnect the internal speaker wires. You would connect the 8 ohm speaker to the extension speaker jack. This jack is an 8 ohm tap on the Output Transformer. You can only use one speaker, but this is safe as long as you follow these instructions.

Be sure to tape off the internal speaker wires so that they don't short on anything.

Otherwise, I recommend only using 16 ohm speakers or enclosures with these amplifiers.


Classic 50 Combos:

The internal speakers on these amplifiers should be connected to the 16 ohm jack.

The other (8 ohm) jack is intended for use with an extension speaker enclosure. The extension should also be 16 ohms.
There is a switching system in this jack, which uses separate taps on the output transformer. When an external speaker is connected, both 16 ohm speaker systems are now in parallel and the amp's transformer is selected to 8 ohms.
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Don't miss PVTV!

Post by Roger Crimm » Fri Nov 21, 2008 8:44 am

PVTV on YouTube is a great resource for tech tips, product demos, and artist interviews. There are frequent updates, so if you haven't checked lately you may be missing out.

Link:

https://www.youtube.com/PeaveyElectronics
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My Amp Is Broken....Help!

Post by Roger Crimm » Thu Feb 26, 2009 4:37 pm

Sorry, but we can't fix it on the forum, and you should not attempt to fix it at home.

From the Important Safety Instructions found in the back of every Peavey owners manual:

"The user should not attempt to service this equipment. Refer all servicing to qualified service personnel”.

Don't mess around with it! If you do, you risk damage to the amp, not to mention a safety hazard to yourself.
I am not trying to make the amp techs rich, nor do I get a kickback for posting this. I just want our customers to be safe and happy with their products.

My advice is to refer all servicing to qualified personnel. There are dangerous voltages present inside any electronic device, even if the unit is unplugged and the power is off. Do not attempt to service an amplifier yourself!
All Peavey dealers are Authorized Service Centers. We also have many independent Authorized Peavey Service centers. We are also offer factory service. With this level of service available, you should have no problem having your Peavey product serviced.


In other words, if you have to ask why your amp doesn't work, it is best to have a qualified repair tech take care of the problem.

If you need assistance finding a service center or dealer, you can use the Dealer/Service Center Locator here:

http://www.peavey.com/support/dealerlocator/

Select “Peavey Service Center” on the drop down menu.

You can also return it to the factory for service. The address is:

Peavey Service Center
412 Hwy 11-80 East
Meridian, MS 39301
Attn: Repair

* Please be sure to specify ATTN: REPAIR on any packages or labels. Include a note with a description of the problem. If you wish to get an estimate before any work is done, please indicate this in your note. No RA is required.


http://www.peavey.com/support/technotes/repair/faq.cfm

If we can be of further assistance, you can call Peavey Customer Service (toll free in the US) @ 1-877-732-8391.

Outside of the US and Canada, please contact your local Peavey Distributor for assistance.
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Footswitch Wiring Guide

Post by Roger Crimm » Tue Aug 25, 2009 4:04 pm

Here is a PDF of the wiring guide for many of the older Peavey Amplifiers.


These are all obsolete (no longer stocked), but you can usually find them "after-market" if you don't want to try and "roll your own"...
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Wiring Guide '95.pdf
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Transformer PC Editor

Post by Roger Crimm » Fri Nov 04, 2016 2:16 pm

Editor for the old Transformer 112 and 212 amplifiers.

Other tech support on those models by the design engineer, John Fera:

http://virtuososo.com/Tform/

.
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tformer.zip
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