Hello everybody, I hope you''ve found some time to try all the mods on your Epiphone Valve Jr. amp we discussed last month and that you finally found the
Hello everybody, I hope you''ve found some time to try all the mods on
your Epiphone Valve Jr. amp we discussed last month and that you
finally found the tone you like.
To close out our Epiphone adventures, this month I will show
you how to add some really useful features to this amp to make it much
more versatile and flexible. Again, all these mods are shown for the
second generation of this amp, which was sold from approximately March
2006 to today as the combo or the "head only" version, but there is
good news - all the mods will also work for the first generation of
this amp without any additional work. So pull out your soldering irons,
heat them up, unplug the amp, and discharge the capacitors.
Before we start, I''m sure you know what''s coming next:
Do not attempt to perform these mods if you are not familiar with
working inside tube amps or other high voltage electronics. There are
lethal voltages inside the amp, even when unplugged (if the filter
capacitors have not been discharged) and these voltages can cause
serious injury or kill you. If you are unsure, take it to an amp tech.
If you decide to perform these mods, you assume all responsibility for
anything that happens! Whether the amp explodes, you get zapped, or the
amp suddenly increases in value because everyone falls in love with it,
it''s all because of you. The glory, the pain, whatever, they''re all
yours. If you can''t live with that, don''t mess with the stuff here.
I apologize for telling you this over and
over again, but I want to see all of you here next month in a good
health, so please take care of what you are doing inside the amp.
If you are missing the circuit drawing of our Epiphone amp, here it is again. Print it out and put it on your workbench to follow along.
To begin, we will perform a very easy to do modification and add a standby switch to our amp. A standby switch can extend tube life dramatically. When you turn on your amp, make sure that the switch is always in the standby position, wait a minute and switch to the play position. Likewise, when you shut down your amp, always switch over to the standby position first. Such a switch is also a good help when you take a break without shutting down your amp - make sure that you engage the standby mode before you have a Coke, as you don''t need a full throttled tube during this time!
All you need is a Carling SPST switch. Drill a hole for the switch on the right side of the amp''s on/off switch and install the new switch; there will be plenty of space for it. All you have to do now is simply connect the switch between the T2 wire and the T2 terminal, that''s it!
Next we will add gain control, also a very easy and effective mod for your amp. The basic idea of this mod is to replace the R7 "gain resistor" with a pot, which is of course a variable resistor.
All you need for this is a quality CTS 1M audio pot. Remove R7 from the PCB and connect the pot as shown on the drawing below; it''s a good idea to use shielded cable for this operation. Place the new pot on the right side from the volume pot, just between the on/off switch and the volume pot. Do not place it on the left side from the input jack - you will see why later on.
Now it''s time for an effective tone control for your Epiphone amp. For this, you''ll need a CTS 1M audio pot with integrated switch, a 470pF silver mica cap, a 0.0047uF cap (Sprague Orange Drop cap for a more Fenderish tone or Mallory caps for a Marshall-like tone) and a piece of shielded wire.
The switch gives you the possibility to completely remove the tone control from the circuit, a nice additional feature. The tone control is very similar to the very early classic single tone controls from Fender and Gibson amps. It''s independent from the volume and it''s responsive, capable of cutting or boosting the high mids and the treble.
Please note that for this mod it is necessary to have the stock 1M resistor at R6 - don''t remove it when you want to have the tone control! If you removed it as a mod, put it back in, otherwise the tone control will have no function. So let''s start and connect everything as shown in the drawing below (looking at the back of the pot):
Now the tone control gets added across the R6 resistor. Solder the black wire coming from the 470pF cap to the end of R6 closest to the edge of the circuit board. Now solder the red wire from the switch/center pot lug to the end of R6 farthest from the edge of the circuit board. Solder the shield wire from the pot case (and the 0.0047uF cap) to the ground-jumper wire marked JP2 and you are done.
To install the tone control, it''s important to place it on the left side of the input jack, far away from the noisy large capacitor cans and transformers. That''s why I recommend placing the gain control on the other (right) side of the volume pot. You can also mount the tone control on the back of the chassis elsewhere. However, to prevent any noise problems, placement of the control and routing of the shielded wire is important.
As you know, our amp has only 5 watts and so it''s very easy to drive it into saturation for a raw and musical overdriven tube tone, ideal for recording purposes. So all we need now is an additional recording-out (aka "line-out") jack.
From the basics, this is a simple 1:1 copy from the speaker out jack, attenuated to line level. For this, you need to install an additional jack on the back of the enclosure - use an insulated nylon jack for this option! All you have to do is connect the new jack in parallel to any speaker output jack as shown in the drawing below. If you have done the Fender mods from the first column, use the resistor values shown in green; for the Marshall and gain mods from column number two as well as a stock Epi amp, use the values shown in black.
The values depicted will result in a well balanced, line level output and are a good point to start from. Changing them will affect the sound, so feel free to experiment from there. 1/2 watt for the resistors is more than enough for this application, but using higher wattage resistors is OK as well. Also note that metal film resistors will give you a different tone than carbon comp resistors, so feel free to experiment with that.
The sweet spot in terms of resistor values varies from amp to amp and depends on the mods you have done. Anything in the neighborhood of the above resistor values should work, at least somewhat, but you can always start with a pair of pots (perhaps with a minimum resistance in series) to set the sweet spot. Once you find the sweet spot, you can wire in resistors of as close values as you can find. And don''t forget to keep the speaker plugged in!
Another very popular way of adding a lineout option is the so-called "Herzog network" as shown below.
You can use this lineout for recording purposes or to connect it to the input of another guitar amp, PA, etc. There are lots of possibilities, so feel free to experiment.
|8-ohm Speaker Output Jack|
To close I will show you how to install an additional 8-ohm speaker output jack. When you own the "head only" version of the amp, you are a lucky camper, as you will find 4, 8 and 16-ohm speaker out jacks on the back of your amp to connect any cab you want to. Combo owners will only find a single 4-ohm output to drive the internal 8" speaker.
When you have a look inside the amp, you will notice that the speaker out jack is soldered to a very large individual PCB with a lot of free space - this is the place to solder in the new nylon jack, the same type as the 4-ohm speaker out jack. It doesn''t matter if you install the new jack on the right or the left side of the stock 4-ohm speaker out jack.
Drilling the additional hole for the new jack is a bit tricky. I used a cardboard pattern for best results. Please note that it''s not possible to add a 16-ohm speaker out to the combo version with the stock output transformer! If you want or need a 16-ohm speaker out, you will have to replace the OT. So let''s connect the new 8-ohm speaker out - have a look at the pics below.
On my combo, the red OT wire is the 8-ohm and it''s also labeled as such. This goes to the new jack socket "tip". The "sleeve" has the additional ground connection, this is the black cable shown on the pics.
Folks, we are finished! I''m sure you learned a lot while trying all these mods and I hope that I''ve inspired you to try some more DIY amp work, or to build your own "18-watt wonder" from scratch. Using the tone mods from the last two columns and the stuff from this month, you should have a killer amp that will suit all your needs for a long time.
Next month, we will start to talk about the primary tone of your axes and how to enhance it, so your soldering irons will have the chance to cool down a bit. Happy soldering and we''ll see you all next month!
Dirk Wacker has been addicted to all kinds of guitars since the
age of 5 and is fascinated by anything that has something to do with
old Fender guitars and amps. He hates short scales and Telecaster neck
pickups, but loves twang. In his spare time he plays country,
rockabilly, surf and Nashville styles in several bands, works as a
studio musician and writes for several guitar mags. He is also a
hardcore DIY guy for guitars, amps and stompboxes and also runs an
extensive webpage (singlecoil.com) about these things.
Kick off the holiday season by shopping for the guitar player in your life at Guitar Center! Now through December 24th 2022, save on exclusive instruments, accessories, apparel, and more with hundreds of items at their lowest prices of the year.
We’ve compiled this year’s best deals in the 2022 Holiday Gift Guide presented by Guitar Center.
DiMarzio, Inc. announces the Relentless P (DP299), the Relentless J Bridge (DP301), Relentless J Neck (DP300), and the Relentless J Pair (DP302) for 4 string basses.
DiMarzio, Inc. announces the release of the Relentless P (DP299), the Relentless J Bridge (DP301), Relentless J Neck (DP300), and the Relentless J Pair (DP302) for 4 string basses. The new Relentless P and Relentless J series pickups feature the Relentless cover designed in collaboration with Billy Sheehan.
As with the Relentless pickups, we removed all the hard edges from the standard P Bass and standard J Basspickups, and added an arch to the top of the pickups to bring the sensing coils and pole pieces closer to the strings. These improvements increase the dynamic range and make active circuitry unnecessary.
The Relentless P and Relentless J pickups incorporate Neodymium magnets and produce 70 percent more output than traditional passive pickups, and they’re dead quiet due to the incorporation of metal covers and foil-shielded cables. To dial in (or fine-tune) the individual string output, the Relentless P and Relentless J include eight adjustable pole pieces. These pickups also have a broad magnetic field so you can even bend notes without volume dropout.
DiMarzio’s extra shielding makes the Relentless P and Relentless J better for both recording and stage performances. We’ve mounted them onto robust .09375” thick circuit board base plates to eliminate the annoying protruding mounting screws — ultimately creating a more comfortable and consistent foundation to rest your fingers on.
The new Relentless P steps beyond the traditional P-Bass sound and can only be described as massive. It has more of everything: more volume, beefier lows, a growling midrange, and crispy highs with better individual string definition.
The Relentless J incorporates a new invention, (patent pending) parallelogram-shaped coils, offering an expanded mid-range punch, snappy highs, precise lows, and a new dimension to the sound of the Relentless series pickups.
Relentless P and Relentless J pickups will breathe new life into any bass, increase playability, and work well for any style of music from Motown to metal.
DiMarzio’s Relentless P, Relentless J Bridge, Relentless J Neck, and Relentless J pair are made in the U.S.A. and may now be ordered for immediate delivery.
Suggested List Price for the Relentless P is $169.00 (MAP $119.99).
Suggested List Price for the Relentless J Bridge and Relentless J neck is $155.00 (MAP $109.99).
Suggested List Price for the Relentless J Pair is $296.00 (MAP 209.99).
For more information, please visit our website at dimarzio.com.
Mystery Stocking is coming soon! Sign up for PG Perks below so you don't miss it.
Sign up for PG Perks on the form below to make sure you don't miss the launch announcement!
About Mystery Stocking
Each year, Premier Guitar likes to put out these mystery boxes as a part of bringing some fun to the holiday season. Remember, this is supposed to be a fun holiday treat! If the contents of this box will ruin your holiday, deplete the last of your bank account, or end your ability to see the good in humanity, it may not be for you.
- This year's Mystery Stocking will cost $44.95. ($39.95 + $5 Flat shipping)
- Each box will be guaranteed to contain $40 or more in value.
- US only. (Sorry World.)
- Make sure your shipping address is correct.
- Have your credit card ready to go before you refresh the page. Paypal is not available. Autofill may not fill in your information.
- There will be NO REFUNDS given.
- There has been a huge demand for these in the past. We really did sell out in less than 4 minutes last year. When they are gone, they are gone.
- One per household, one per person.
Q: What's in the Mystery Stocking?
A: It wouldn't be much of a surprise if we told you, now would it?
Q: Will I definitely get my money worth?
Q: Can I return it if I don't like it?
A: Nope. All sales final.
Q: What if I live outside the US?
A: Sorry, US only.
Q. How much is it?
A. $39.95 Plus $5 shipping
Q. When will it ship?
A. On or before December 10, 2022.
Q. What form of payment do you accept?
A. Credit cards only. Sorry, no Paypal for this.
Q. Can I ship to a different location than my billing address?
Q. I tried last year and didn't get one. Will I get one this year?
A. There is an overwhelming demand for Mystery Stocking. Be sure you have a fast internet connection and be ready when they go on sale. Last year we sold out in 3 min 33 seconds.
Q. I want to buy 5. How can I buy 5?
A. You can't. This year, we're limiting to one per household, so more people can get in on the fun!
For part two of our crash course in harmony for bassists, we’re talkin’ triads.
As bass players, our job is often to indicate and support what is happening rhythmically and harmonically in the music we’re playing. And to do that, it’s important for us to understand the basics of tonality and how it works. In fact, every bass player must have a strong knowledge of harmony to do their job correctly. This month, we’ll continue last month’s harmony crash course with some more ways to brush up on your ear skills, in italics below, so you can do your low-end job effectively.
The basic building block of harmony is the dyad, which gives us our basic intervals. But the basic building block of tonality is the triad, a grouping of three or more tones (root, 3rd, and 5th) that give us the four chord qualities—major, minor, diminished, and augmented—which you’re probably already familiar with.
Just as with intervals, we should train our ears to recognize chord qualities instantly. Start with two qualities (major and minor). Once you can identify those two correctly about 95 percent of the time, add another. Keep going until you can identify all four qualities consistently.
Another great exercise is to take a melody (either major or minor) and convert it to the opposite quality. Start out with something you know well, like “Twinkle, Twinkle, Little Star.” This may take a while at first, but the goal is to keep on doing these until you can convert most stuff on the fly instantly.
“This feeling of resolution, in some ways, is the whole point.”
Each chord quality has its own distinct sound, but major and minor are related, and both feel very grounded. Because of the 5th in each, our ears can easily hear which note in the chord is strongest (the root), which gives major and minor a sense of gravity. This feeling persists even if we change the order of the notes (invert the chord).
Have a friend or an app play inversions of major or minor triads. Find the root of each chord by singing it. Work towards being able to identify these triads in root position (root in the bass), first inversion (3rd in the bass), or second inversion (5th in the bass).
Pay attention to bass lines that land on a root, 3rd, or 5th on the first beat of the bar and then practice coming up with your own examples.
Diminished and augmented triads are much more ambiguous. Without a perfect fifth (diminished has a b5 and augmented has a #5), no tone in particular sounds strongest. Thus, both chords lack gravity. In fact, to most of us, every tone sounds equal, like being lost in the woods where every direction appears the same. Both seem to want to move towards something else more stable. When this occurs, it gives a sense of release, or resolution. This feeling of resolution, in some ways, is the whole point.
The top part of a dominant seventh or V7 chord is a diminished triad. For example, a C7 consists of the notes C–E–G–Bb. If you remove the C, we’re left with an E diminished triad. This is where the moving sound, or the desire to resolve, comes from. The important takeaway is that we’re making something very stable—a major chord—and making it less stable when we add the b7, because of the diminished sound, which in turn sets up the need to resolve.
Listening for V–I: On a guitar or keyboard play any major chord, then add a b7 (transforming I to V7) and try to hear where the progression “wants” to go next. Move to the new key (a fifth down) and repeat. After twelve V–I progressions you’ll arrive back at the original key.
The Dominant Gateway: On bass, try playing a walking bass pattern over the cycle of fifths, strategically using a b7 to move to the next key. This foreshadowing is a great voice-leading skill.
That's all for our crash course in harmony. If you take your time with these exercises, you should notice not only your ears improving, but your bass playing too!