aztechmusic http://aztechmusic.com how to repair guitar amps, synths and other music gear Tue, 12 Aug 2008 02:13:40 +0000 http://wordpress.org/?v=2.5 en How to use a Volt Ohm Meter Part 1 http://aztechmusic.com/33/how-to-use-a-volt-ohm-meter-part-1/ http://aztechmusic.com/33/how-to-use-a-volt-ohm-meter-part-1/#comments Mon, 30 Jun 2008 22:30:06 +0000 Gary http://aztechmusic.com/?p=33 Here is a good video on how to use a volt ohm meter. He explains in one example how to test for continuity. (circuit has little or no resistance between two points)

This is very important when troubleshooting a circuit. One example is you might find ” a short” which means the same thing as no resistance. And you may find it where you shouldn’t find it. You will know this either by experience or by looking at a wiring diagram/schematic.

Let’s say you know by looking at a circuit board that a capacitor is between the input jack and the first part of a circuit. Since a capacitor blocks DC but passes AC and you hear your meter’s speaker or see zero ohms by placing you leads on each side of the capacitor. This could be a clue why your amp is not working correctly.

Watch this video, he will touch on the different parts of the meter and what it does.

At the end of the video he suggests getting a Fluke meter. I would definitely second this. Even know a cheapo from the hardware store will work in a tight situation.

Think of your repair gear like having good music equipment. Sure, you can show up at the recording date with a cheap guitar with bad keys and get it done. But you know if you have a quality guitar with good tuners, you will be able to concentrate on your recording, not your equipment.

Fluke 117 Multi meter
US $81.00 (3 Bids)
End Date: Tuesday Oct-07-2008 6:42:07 PDT
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FLUKE 117 TRUE-RMS MULTI-METER w/ VOLT ALERT TECHNOLOGY
US $100.00 (25 Bids)
End Date: Tuesday Oct-07-2008 8:45:55 PDT
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]]> http://aztechmusic.com/33/how-to-use-a-volt-ohm-meter-part-1/feed/ Fender Amp Power Supply Problem http://aztechmusic.com/32/fender-amp-power-supply-problem/ http://aztechmusic.com/32/fender-amp-power-supply-problem/#comments Wed, 18 Jun 2008 18:59:26 +0000 Gary http://aztechmusic.com/?p=32 This video found on YouTube is a perfect example of a filter cap problem. On solid state units like this one, through vibration and assembly techniques, components can work themselves lose from the circuit board. The owner greg1485 from this video literally has his finger on the problem.

In a perfect situation with a trained tech this would be a quick repair but for someone with no experience or just starting out it would take awhile or it’s time to take it to a shop. What you’re hearing is when he applies pressure to the long barrel cylinder looking things, is non-rectified (AC) getting into the audio circuits via the power supply feeds.

This is the main job of the power supply capacitors, to smooth the AC being rectified by power diodes that are looking at the secondary of the power transformer.




If I remember correctly on this unit the entire circuit board would need to come out of the chasis. This is done by all knobs and nuts and lock washers on the front. Screws holding the board from the top and screws on the bottom holding the power transistors heat sink in place. Pull the board up and resolder the caps to the board. (may have some wires to disconnect also, so you would make a note where everything is connected)

Replace the mica thermal film on the power transistors. Clean and replace the heat sink compound, carefully reinstall the board. Triple check your work was done properly. (a quick check with your volt/ohm meter from the output transistor to ground should tell you everything is ok. For instance you should have a resistance reading from the metal of the transistor touching the mica film, to the chasis. How much can vary, the important thing is not to see zero ohms)

Bring up unit on a variac slowly to check your work one more time. Inject signal and watch for perfect sine wave on the scope, then test out the amp with a guitar. You can always do a power check to make sure the amp is ready to go.

And wa-la you have a happy customer!

DVD REPAIR TUBE GUITAR AMPS fix troubleshooting Fender
US $68.98 (1 Bid)
End Date: Monday Oct-06-2008 23:16:35 PDT
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]]> http://aztechmusic.com/32/fender-amp-power-supply-problem/feed/ BOSS FDR-1 Fender Deluxe Reverb Pedal http://aztechmusic.com/31/boss-fdr-1-fender-deluxe-reverb-pedal/ http://aztechmusic.com/31/boss-fdr-1-fender-deluxe-reverb-pedal/#comments Tue, 10 Jun 2008 20:37:06 +0000 Gary http://aztechmusic.com/?p=31 This Legend Series Pedal is incredible in the sense that if your amp doesn’t have reverb or vibrato, it does now!

Uses COSM technology to model the amp sound of a Fender DELUXE REVERB®.

Features reverb and vibrato effects like those on an actual
DELUXE REVERB®amp.

Boss FDR-1 Fender Deluxe Reverb Pedal at Musicians Friend

user ratings from music web sites
Not only that it is a great effects pedal, check out the the spring reverb sound. The vibrato is good, especially in a recording situation. I believe the player’s name is Phil Gates. Great demo:




Nominal Input Level:………………….. -20 dBu
Input Impedance:………………………… 1 M ohm
Nominal Output Level:……………….. -20 dBu
Output Impedance: …………………….. 2.2 k
Recommended Load Impedance:… 10 k or greater
Controls:……………………………………… Pedal switch, GAIN knob, LEVEL knob, TREBLE knob,
BASS knob, REVERB knob, VIBRATO knob
Indicators:………………………………………CHECK indicator (for effect on/off status and battery check)
Connectors:…………………………………. INPUT jack, OUTPUT jack, AC adaptor jack (DC 9 V)
Power Supply:…………………………….. DC 9 V: Dry battery 6F22 (9 V) type (carbon)/
Dry battery 6LR61 (9 V) type (alkaline)
AC Adaptor (PSA-series: optional)
Current Draw: …………………………….. 40 mA (DC 9 V)
* Expected battery life under continuous use:
Carbon: 2.7 hours, Alkaline: 9 hours
These figures will vary depending on the actual conditions of use.
Dimensions:………………………………… 73 (W) x 129 (D) x 59 (H) mm /
2-7/8 (W) x 5-1/8 (D) x 2-3/8 (H) inches

Boss FDR-1 Fender Deluxe Reverb Pedal at Musicians Friend

Boss FDR-1 Fender Deluxe Reverb Pedal

These are a few that are found on eBay.

BOSS FDR-1 FENDER '65 Deluxe Reverb-Amp Guitar Pedal
US $57.10 (15 Bids)
End Date: Tuesday Oct-07-2008 18:43:16 PDT
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BOSS FDR-1 FDR1 FENDER 1965 VINTAGE DELUXE REVERB AMP
US $127.95
End Date: Tuesday Oct-07-2008 23:12:41 PDT
Buy It Now for only: US $127.95
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Product Info Specs were found at Fender.com and Rolandus.com

]]> http://aztechmusic.com/31/boss-fdr-1-fender-deluxe-reverb-pedal/feed/ Boss/Roland/Fender: FBM-1 Effects Amp Pedal http://aztechmusic.com/30/bossrolandfender-fbm-1-effects-amp-pedal/ http://aztechmusic.com/30/bossrolandfender-fbm-1-effects-amp-pedal/#comments Wed, 04 Jun 2008 00:58:48 +0000 Gary http://aztechmusic.com/?p=30 Here is an incredible pedal by Boss. Usually when I see/hear a modeling pedal it’s close but no cigar.

Is this pedal as good as a cranked up 59 bassman? …of course not. But what you could do is run it parallel to the amp. For instance y-cord or go through a mixer where half your signal hits the amp, the other goes through the pedal and then hits the amp.

Live this might be kind of a hassle so you run it straight. Boss is getting close with this though. I could see/hear where this could make a so-so amp stand up and bark.

Check out this video:



Nice playing by Johnny DeMarco also.

Here is a collection of reviews:
Most agree that this pedal really helps clean amps to be more versatile.
Leave the amp eq flat and use the pedal eq.
Tube amps love this pedal, doesn’t do much for the small practice amps.
Great for Blues and Overdriven country.
Makes the bridge pickup of a strat have more bite.

Boss FBM-1 Fender Bassman Pedal Musicians Friend

Boss FBM-1 Fender Bassman Pedal

BOSS FBM-1 FENDER '59 BASSMAN PEDAL LEGEND SERIES FBM1
US $148.00
End Date: Tuesday Oct-07-2008 15:57:07 PDT
Buy It Now for only: US $148.00
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BOSS FBM-1 FBM1 FENDER TWEED BASSMAN AMP PEDAL
US $149.00
End Date: Tuesday Oct-07-2008 23:24:41 PDT
Buy It Now for only: US $149.00
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]]> http://aztechmusic.com/30/bossrolandfender-fbm-1-effects-amp-pedal/feed/ Soldering Audio Cable http://aztechmusic.com/29/soldering-audio-cable/ http://aztechmusic.com/29/soldering-audio-cable/#comments Sun, 11 May 2008 16:59:30 +0000 Gary http://aztechmusic.com/?p=29


Here is a good video I got off of YouTube where a gentleman is demonstrating how to tint the end of wires. He has a cool cable holder, looks like part of a guitar pickup spring load system that he modified.

You can use anything, I use vice grip pliers a lot because they are handy. Just be sure not to tighten them down too much or you will nick the metal of the jacks. There is all kinds of commercial wire holders if you look around. I’m sure there are roadies that can hold the wires in their teeth as they solder. LOL




One other thing is I would put a fan on my work space to suck out the fumes. You don’t really want the fumes up in your face. If you are going to do a lot of soldering there are different commercial ways to deal with fumes.

Also as an added tip, always buy the best tools and soldering equipment you can afford when starting out. Repair equipment is no different than music gear, you can start out with the cheap stuff but as your chops grow you always go back and buy what you wished you had bought in the first place. Am I wrong?

soldering iron tip for weller microtouch station- New
US $35.00 (1 Bid)
End Date: Tuesday Oct-07-2008 9:32:37 PDT
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Weller WESD51 Soldering Station & PES51 Iron
US $50.99 (2 Bids)
End Date: Tuesday Oct-07-2008 12:01:27 PDT
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]]> http://aztechmusic.com/29/soldering-audio-cable/feed/ Tube Glove for Hot Tubes http://aztechmusic.com/28/tube-glove-for-hot-tubes/ http://aztechmusic.com/28/tube-glove-for-hot-tubes/#comments Mon, 28 Apr 2008 16:05:29 +0000 Gary http://aztechmusic.com/?p=28 This is a short video on a tube glove. I’ve used many things but there’s nothing that beats a tube glove. It’s always best to let tubes cool down before moving them around but there are times when this is not possible.



The tube glove for guitar amps enables you to get a firm grip on a hot tube and gently set it down or move it to a new socket. This one is made by electro-harmonix and is a must have if you are handling tubes.

]]> http://aztechmusic.com/28/tube-glove-for-hot-tubes/feed/ Audio Signal Generator Demo http://aztechmusic.com/26/audio-signal-generator-demo/ http://aztechmusic.com/26/audio-signal-generator-demo/#comments Fri, 18 Apr 2008 17:07:14 +0000 Gary http://aztechmusic.com/?p=26 This is a Loftech TS-1 signal generator. A little used, missing knob cover on the frequency knob. Very versatile unit and rugged. Holds it’s calibration pretty well. This is an older unit. There are newer ones and rack mount versions also.

In this video I’m running right into a speaker cabinet. Using a small power amp you can just about test any speaker combination. Great for testing crossover points, finding defective horns and speakers.

Great tool for testing frequency response on rack gear.




You see these units from time to time on the net at great prices. If you get the chance to buy one you won’t regret it. If you can’t find one, I would recommend getting a generator with a variable frequency knob instead of incremental switches.

One place you can’t skimp is your test equipment. Make sure whatever signal generator you get gives you a rock solid perfect sine wave on your scope.

Sale ! New Audio Signal Generator (15Hz-1.5MHz) - T101
US $135.99
End Date: Monday Oct-06-2008 23:28:01 PDT
Buy It Now for only: US $135.99
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Sale ! New Audio Signal Generator (15Hz-1.5MHz) - T101
US $135.99
End Date: Tuesday Oct-07-2008 11:34:39 PDT
Buy It Now for only: US $135.99
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]]> http://aztechmusic.com/26/audio-signal-generator-demo/feed/ BlackHeart Amp Little Giant for Guitar http://aztechmusic.com/22/blackheart-guitar-amp-little-giant/ http://aztechmusic.com/22/blackheart-guitar-amp-little-giant/#comments Thu, 10 Apr 2008 13:23:10 +0000 Gary http://aztechmusic.com/22/blackheart-guitar-amp-little-giant/ This one is very cool. I got this video by toyhouse off of youtube. To me this is what it’s all about. Shows him (I’m assuming it’s a him, there is a hairy arm in the movie) unpacking, how he mics, the recording gear. Great song, great recording and production.

FORGET THE VIDEO I JUST MENTIONED, CHECK OUT THIS KILLER VIDEO:

The amp is by Blackheart Engineering, a subdivision of LOUD Technologies. Which owns Mackie and Crate I believe. It’s supposed to be a hot rodded version of the Epihone Valve Junior.

Model: BH15-112

5 WATT, single-ended, Class A combo, powered by an EL84 and voiced through a 12AX7 preamp tube.
With switchable pentode/triode selector and 3-band EQ.

SPECS:

* » 15 Watts, Push-Pull, Class A
* » Outputs: 1 x 16 ohm jack, 2 x 8 ohm jacks, 2 x 4 ohm jacks
* » Solid State Rectifier with tap for future mods
* » Drive, Level, Treble, Mid, Bass and Presence controls
* » Pentode (15 Watts)/Triode (7 Watts) Switch
* » DC Power to filaments for super quiet operation
* » 15 ply (18mm) thick-void free plywood construction
* » 12″ Blackheart Model 1216A Speaker by Eminence with American Voicing, optimized for open back cabinet

I’ll post more info in a little bit on this amp.

Excellent Reviews at Musician’s Friend.

Blackheart amp



————————————————————————–

Sometimes a good used one is on eBay.

THE LITTLE SUCKER- ATTENUATOR - BLACKHEART LITTLE GIANT
US $49.99
End Date: Thursday Oct-09-2008 23:22:16 PDT
Buy It Now for only: US $49.99
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Blackheart Amp "Little Giant"
US $113.50 (2 Bids)
End Date: Sunday Oct-12-2008 18:59:38 PDT
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If a Peavey Rockmaster Preamp comes available on eBay it will post here.

]]> http://aztechmusic.com/22/blackheart-guitar-amp-little-giant/feed/ Tube Amp - Bent Tube Pins http://aztechmusic.com/21/tube-amp-bent-tube-pins/ http://aztechmusic.com/21/tube-amp-bent-tube-pins/#comments Thu, 27 Mar 2008 16:01:39 +0000 Gary http://aztechmusic.com/21/tube-amp-bent-tube-pins/

This video shows how I straighten bent tube pins. Try to be careful when you insert your tube into a tube socket. If you look at the socket, you will notice an blank space (no hole). Align your tube accordingly.

Never force, but sometimes takes a little pressure to get the tube inserted. You always want a tight secure fit.
When a tube socket goes bad or wears out, it will need replacing. Usually this happens on older amps.

On the larger output tubes and rectifier tubes to maintain a tight grip on the tubes, sometimes all that is needed is to tighten the socket hole metal by placing a small screwdriver between the socket and the metal and bending. THIS IS DONE AFTER THE POWER SUPPLY HAS BEEN DRAINED OF ALL CURRENT. IF YOU DON’T KNOW HOW TO DO THIS, THEN DO NOT ATTEMPT THIS PROCEDURE.

You want to keep a snug fit by the socket on the tubes at all times. Noise is sometimes generated it one pin does not have a tight fit with the socket. You can eyeball the socket clamps to make sure all look similar.
Sometimes noise can be generated by a loose wire attached to the socket.

old tube amp/ germanium transistor parts
US $20.00 (0 Bid)
End Date: Thursday Oct-09-2008 7:32:05 PDT
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REALISTIC Stereo Tube Amp Model SAE 24D Parts or Repair
US $12.00 (3 Bids)
End Date: Thursday Oct-09-2008 19:06:55 PDT
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]]> http://aztechmusic.com/21/tube-amp-bent-tube-pins/feed/ Fender Hot Rod Deluxe Amp Repair Video Part 2 http://aztechmusic.com/20/fender-hot-rod-deluxe-amp-repair-video-part-2/ http://aztechmusic.com/20/fender-hot-rod-deluxe-amp-repair-video-part-2/#comments Fri, 21 Mar 2008 21:00:37 +0000 Gary http://aztechmusic.com/20/fender-hot-rod-deluxe-amp-repair-video-part-2/

In this amp repair video, I’m showing how to clean the pots. Just a little spray into each (small opening in the pot casing) and then work the knob.

I WOULD RECOMMEND TURNING OFF THE AMP AND UNPLUGGING FROM THE WALL FIRST.

Clean the jacks also and make sure they are nice and tight to the feel. By that I mean plug in and out the guitar chord to make sure there is a tight grip. If not, I recommend changing the plug which will require solder/unsolder chops on these units. Notice the soldering video, I will cover unsoldering in another video.

Fender Hot Rod Deluxe Tube amp Amplifier 180 w
US $549.00
End Date: Tuesday Oct-07-2008 15:09:05 PDT
Buy It Now for only: US $549.00
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FENDER AMP COVER ~ HOT ROD DELUXE
US $18.95
End Date: Tuesday Oct-07-2008 21:12:09 PDT
Buy It Now for only: US $18.95
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]]> http://aztechmusic.com/20/fender-hot-rod-deluxe-amp-repair-video-part-2/feed/