Archive for December, 2015

I wanted to give my deepest gratitude to all of the people who have visited this blog in 2015.  My statistics for visits and engagement aren’t massive (and I don’t expect that), but they exceeded my goal by more than 200% and my total page views were more than a 4000% increase over 2014.

In particular, the members of the Mesa community at The Boogie Board have provided inspiration, feedback, questions, critique, and support that helped shape the way information was presented in regard to the articles about the Dual Rectifier.  Thank you, very much.

As well, a handful of people from the Music Electronics Forum visited to check my work and I am incredibly grateful for the time and feedback from those who helped.

I hope everyone has an awesome 2016.  Cheers.

Searching For Good Fretwork

Posted: December 27, 2015 in DIY, Guitar
Tags: , , , , , , , , ,

Yesterday, I wrote about searching for inexpensive guitars with good fretwork to upgrade into higher performing instruments.  I didn’t really go into detail about what good fretwork is.  The reason was that there are literally thousands of articles, posts, and instructions about fretwork that can be found by using Google.  There are a few basic things to look for, though.  So, I pulled up the El Cheapo, Microsoft Paint to illustrate the basics.  For greater detail, Google is your friend.

Different companies do different things with the fret ends and there are other considerations, like binding.  However there are some warning signs to look for when inspecting an instrument. (more…)

I have never had a lot of money.  My only major investment toward playing music has been my Dual Rectifier.  Guitars costing over $800 have been out of my budget and I figure the same thing holds true for many other people.  Fortunately, mid-priced, mass produced guitars are made with higher quality than just about ever before.

When it comes to upgrading inexpensive guitars, the most important thing is to make sure the neck is well made and the frets are properly installed.  Any hardware or electronics can be easily replaced, but the cost of a major fret job or replacement defeats the purpose of upgrading an otherwise good guitar to be great.

For many years now, I’ve preferred Gibson-style guitars, or at least humbucker equipped guitars, at a more affordable price.  Epiphone G Series, LTD, Schecter C Series, and the like are along the lines of what I could afford and like.  I’m going to speak mainly about these types of guitars, since that’s where my most recent experience is.

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June 2016- I realize the flow of this article could use some work.  I have plans to reorganize it at another time.  

We’ve looked at the input and Clean, the Mode voicing and Gain control, V2 and V3EQ and modes and Presence.  I am going to bring it all together and take a less detailed, wider, view of the system as a whole.  I’m concentrating on Channels 2 and 3, since they are the primary identity; the “Recto” sound.

Additionally, I’m going to cover a little bit about the power amp, even though I have not concentrated on it in my writing this year.  I think the intention of Mesa when designing it is misunderstood.

I’m going to be making certain assumptions based on the overall design and historical precedents in guitar amplifiers and Mesa designs.  I could be wrong, but I am presenting it the way I best understand it, based on how everything interacts, and considering the differences between this amp and others much like it.  Mesa tends to tune their amps by ear, so some of the effects from changes may be unintentional or accidental.  That doesn’t negate the actual effects from being valid points innovation on the design.

For filter analysis, I’m using the Okawa website.

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We’ve looked at the input and Clean, the voicing and Gain control, and V2.  Now, it is time to examine V3, the coupled cathode follower.  I urge you to read about cathode followers if you do not understand how they work and wish to learn more.

The biggest things for a novice to know are:

  • A cathode follower is usually used to lower impedance to drive a tone stack or an effects loop.
  •  The cathode of the second tube follows the voltage on its grid closely (hence “cathode follower”).
  • The first tube provides amplification of the signal and stability to the cathode follower.
  • When coupled (wired together), the two tubes act like one (mostly). (more…)

So far, we’ve looked at the input stage and Clean mode, and the voicing and Gain controls for Channels 2 and 3.  When we left off, the signal had been filtered, dropped down, filtered again, and was exiting the Gain pot by way of a 475 k grid resistor into Stage 2 (V2a).

Grid Resistor

V2aDRAside from controlling incoming current, the grid resistor serves to adjust the highest frequency allowed to enter the amplification stage by creating a filter due to the tube’s internal capacitance (around 1.6 pf).  Additionally, this stage has a 20 pf capacitor in parallel to the tube.  This increases the total capacitance to 21.6 pf. (more…)