Amp problems were actually cabinet problems.

I have had this 50 watt, modded Traynor head for years now. It’s awesome.  However, I notice for my really loud bands (Cartographer and Select Sex), it just doesn’t have the balls to really get over the insanely loud drummers of those bands.

I tried a number of changes. I messed with coupling cap values to tame the low-end and not use up power for frequencies that couldn’t really be heard live. I tried adding a cap to make a high shelf circuit like on many mid to high gain amps. The mods made the amp crunch in a nicer manner, but it didn’t help with the “push” and the volume.  I checked the bias. I hooked the amp up to a scope to check wattage before clipping. It was giving me 49 watts of clean power, and the bias was spot on for me.

I couldn’t figure it out. I had an amp performing well, I had a good guitar, and I had an awesome cabinet. I’ve discussed my cabinet on this blog before. It’s a Lee Jackson cabinet. It’s very well made with nice wood. It has heavy metal associations, but I though the cab sounded great when I got it. You can see the quality construction in this photo.

Cabinet Repair, etc

I’d replaced the speakers, but I was questioning one of my choices. I had picked up a couple Eminence Governor speakers a while back, but I had not put them in.  Finally, a couple of weekends ago, I had some time.  I went down to the practice space and rewired my cabinet. I cross-loaded the two Mesa/ Celestion C90 speakers with the two Governor speakers.  While doing this I noticed something very wrong.  About 3/4th of the screws that hold the speaker baffle to the rest of the cabinet had come loose.  They weren’t just a little loose.  Many had backed out at least three or four full turns.  Some had come out even more.  This is like finding the lug nuts loose on your car wheels, but you know, without having your life in peril.

I tightened up the baffle screws, and put in the Governors with the existing C90 speakers in an X pattern. I sealed it up, but I didn’t have time to play the when I finished. At the next band practice it seemed to cut a bit more than usual and I didn’t have to turn up the amp as much. I played my first show with it last night, and it was really great. The guitar wasn’t getting lost in the cymbal wash, and there was plenty of volume on tap.

This is a problem that has bitten me in the ass again and again.  When I’m having some technical issue, I’ll assume something is okay because it was okay in the past and it has shown no obvious signs of degradation and failure. Because I tend to be an amp circuit guy, I went looking at the amp’s electronics as soon as something seemed amiss. I looked in my comfort zone. If I had taken the ten minutes to unscrew the back of my cab at the first sign of a problem I would have found it long ago and not have spent so much time looking for issues where there were none to be found.

Finally, this is a good reminder that guitar setups are systems.  Even though we buy all of our gear as separate pieces, we run them all together, and they way they behave when run en masss is not necessarily indicative of how they will run when isolated.

Thanks for reading, friends.

Tech Log 2011-03-09

Replaced a switch and battery clip on a 1986 RAT for Jeremy H.

Diagnosed Jason P’s Traynor. Looks like it’s just the wacky standby switch. Now, where do I get one of those?

Tuned up Jon G’s Fuzzy Bunny.

Experimented with the new fuzz circuit.

Worked on Trey P’s Bunnydrive; almost finished!

Pinched the hell out of my finger in a mic stand.

Who needs more iron? I do!

I got this Traynor head from my friend Jeremy of the bands Charmless and Truxton. It had been tweaked and un-tweaked, and just generally seemed a bit rough and needing love. I bought it with one idea in mind; use it as a platform for my ultimate high-gain amp.

Earlier in this log you can see my previous mods. I removed the presence control, I turned that knob into a master volume, I cascaded the gain stages, and I left two gain knobs, allowing me to control the gain level leaving both the first and second gain stages. Essentially, I took a JCM800 circuit, hot-rodded it a bit, and corrected all the stuff I didn’t like about it. The result is a crunchy amp with more gain and a much wider range of tones.

During all this work, I noticed that the output transformer was a bit small. Okay, it was more than a bit small; it was smaller than the stock output transformer on my Pro Reverb, which can handle roughly 35 watts. I thought maybe this was the reason the head seemed not very loud, and to squish out earlier than expected on the master volume knob. Many people would like this aspect, since it was a little quieter when saturating. I play in a band with Chris Bolig on drums, who is, whithout a doubt, the loudest drummer I have ever seen, let alone had as a band-mate.

I was hoping a new transformer would give the amp a bit more volume and force. By force I mean that kind of hard to define “whump” that ones feels when say a low palm muted chord is played on an amp with high headroom. Plus, the traynor only had an 8 ohm out. Having 4, 8, and 16 ohm taps would be a great improvement for me. I noticed that Triode Electronics has a very reasonably prices 50 watt Marshall replacement transformer. I was already ordering a tranny to fix my pal Scott’s Alamo amp. What the hell, I grabbed the Marshall tranny.

Traynor Transformer Replacement

Today I finally found a big block of unused time. I decided to swap the transformers, and record the before and after.

Here is the mic setup.
Traynor Transformer Replacement

And here was how I set the knobs.
Traynor Transformer Replacement

And here is how it sounds.
Old Transformer MP3

The first thing I had to do was to pull the chassis. On a Traynor, this is INCREDIBLY easy. Remove four big machined screws, and the top of the amp comes off, exposing the guts. Then there are two more machine screws on each side. With the second set of four removed, the chassis comes out effortlessly. It is so much easier than pretty much every other amp.

So within about 10 or 15 minutes I had the chassis out and the old transformer removed. For a comparison, here is the old transformer next to the new one.
Traynor Transformer Replacement

Since the new transformer is significantly bigger, I had to drill holes in the chassis. I would normally shy away from this, but the chassis already had a number of extra holes. This just made me feel better about it. The amp is way past ever doing an immaculate restoration job. Plus, it’s one of the least desirable years of the YBA-1.

Here is the new transformer being mocked up.
Traynor Transformer Replacement

And here are the new holes I drilled, as shown by my pointing tools.
Traynor Transformer Replacement

The hardest part followed. I had to fit all the new wires into the amp through the one access hole, and then under the circuit board. Plus, the transformer was heavy and it had to be held in place without yet being mounted to do this. I devised a system of setting the chassis vertically and propping the new transformer close to its final position while gently weaving the wires through the inside of the amp. I was a bit too occupied to take photos. I got everything in, bolted the chassis, routed everything, trimmed the wires, and soldered everything in.

Then I had to drill the final hole. There were two speaker outs on the amps already. I had three taps for the impedance options. Rather than putting in a switch, I just added a third speaker jack. Here is the end result.

Traynor Transformer Replacement

And here are the jacks from the inside.
Traynor Transformer Replacement

So it was all wired up, labeled. The only thing to do now was to put the tubes back in and make sure it worked. I set all the knobs back to where they were, and recorded the same audio bit.
New Transformer MP3

The result: there was a slight difference, but not a ton. However, this was only at that specific volume and gain setting. One thing that does not translate is that if you’re in the room, there is a definite feeling of pushing a bit more air that wasn’t there before. Also, when cranking it up, the power saturation starts later, and the amp is just a touch louder. The low frequencies are a bit more defined, meaning they have more transient response and don’t squish out as much.

For me, I call this a success.

Tech details: Signal chain.

Electrical Guitar Company # 368 – bridge pickup.
Amp.
4-12 with Mesa Black Shadow miked.
57 about 4 inches from the grill.
Metric Halo Mobile IO
Recorded at 44.1/24 then converted to a 192kbps MP3 in Logic

Larger photos here.
http://www.flickr.com/photos/benadrian/sets/72157623098820271/

Electrical Guitar Company & Cartographer Amps

Long time, no speak, friends of my nerdery. January was a very, very busy month. I all but stopped making pedals due to band, recording, and of course day job commitments. the heavy lifting has passed. Now, let me play catch up on some of the stuff that did happen.

On February 5th, after about six months of waiting, my Electrical Guitar Company “Custom 500” arrived.

Yes that is an aluminum neck and fretboard. In fact the neck goes all the way through the body and the bridge bolts directly into the neck. Here is the guitar with the body removed.

You can see more and hi-res photos here.
http://www.flickr.com/photos/benadrian/sets/72157623243036439/

This is just an amazing instrument. Rather than type a whole new description, I’ll just copy what I wrote to the builder.

—–
The sound is amazing! On tour in late 2007 I played Rich’s all aluminum offset one, and then Colin from Fun Ender’s guitar. The feel wigged me out at first, but after about 10 minutes I just couldn’t put them down. I never played them plugged in, though.

On Saturday I got to plug it in. A few friends who were practicing down the hall came by to check it out. The range of tones available is very diverse. The RW/RP of the pickups is a great bonus. Mainly, though, what everyone noticed what the immediacy of the response. I never got that before when playing the guitars unplugged. The think I’m telling my friends is that it has the attack of a Tele, but the level drops off less for the
sustain. It’s like a Fender response with more sustain, or a Gibson response without the weak, mushy attack . It’s just a totally unique ADSR curve (synth term)

The other thing I told my friends is that it kind of sounds like an angrier, more responsive version of my Ric 360.

The pickups, holy shit! they sound great, yeah, but I had my amp running at full tilt, standing right in front of it, and there was no squeal at all. I couldn’t get microphonic feedback at all. So great!

So yeah, I’m blown away. Fit, finish, sound; I played it all weekend in every little open moment.
—–

So yes, new favorite guitar by far.

I also finally settled on my Cartographer amp setup. I finished the Traynor. I left the tone caps the way they were, but I redid the phase inverter circuit to classic Marshall values. Instead of a 2-12, I managed to grab an inexpensive but good 4-12 from my friend Jeremy. the other amp is half of my old bass amp from Replicator. It looks very intimidating.

That’s the full catchup. Look for more building and repairing soon.

Traynor Head… Canadian Weirdness.

Recently I acquired a mid-to-late 70s Traynor YBA-1 Bass Master head. I’d never seen one like this before. This is the schematic that it pasted to the inside of the head.

http://www.lynx.net/~jc/761014_YBA1_4.gif

Crazy thing was, the schematic didn’t even match the inside of the amp.

Not only was it modified, when I got it. It also seemed to have the midrange and presence control of a YBA3.

What? I’m not your dad, look it up.

Okay, like this. http://www.lynx.net/~jc/721005_YBA3.gif

Well, it sounded kinda blah. Not bad… better than most modern amps… but it was still a bit meh, and it was a perfect candidate for a few simple tweaks. Or in my case, a rude-ass rock machine.

The early Traynors were basically copies of Tweed Bassman amps with a few of the changes that Marshall made when THEY copied the tweed Bassman. The Marshall 2203/2204 circuit (most popularly known as the JCM 800 or JMP MkII) is roughly that same amp with the bright and normal channels cascaded for more gain. I decided to mod it to be a version of the JCM 800 with a few of the JCM 800 from the tone-lizard.com website. I’d already done a few like this to my 6 watt JCM 800 “tiny teabag.”

Here is the “original” circuit

Here is the preamp after my first step of rerouting.

After that I continued wiring the amp. I kinda forgot to take any more pictures. In that second picture I had just finishe cascading the first two gain stage. The cathode on gain stage one is a 2.2k resistor and .68uf cap. The second gain stage has a 10k resistor. These values are both pretty close to JCM 800.

The one thing I did change was the series resistance in between gain stages. The JCM 800 has 470k resistor jumpers by a 470 pf cap in line before the 1M gain knob. I used a 100k resistor with a 500k pot, no cap. It keeps it not so horribly bright.

From there it went pretty easily. Instead of the 470k/470k voltage divider, I used a 500k pot. I’m hoping the lower overall value will take the high frequency down a bit more. Following that I restored the tone stack to the bassman/plexi setup, but using the existing component values from the Traynor, which were a .1uf bass cap, and a 1000pf treble cap. The Bassman values are .022uf and 500pf. I think I’ll keep the .1uf, but I’ll try a 500pf instead of the 1000pf.

Siince I removed the weird mid/presence, and the presence wasn’t part of the negative feedback loop, I just left the presence out. The old presence knob became the master volume.

So far, the amp rips. It just wants to cut off the heads of mythical beasts. Look our minotaurs! Next up is to check the phase inverter values. They seemed a bit low. Plus I wanted to play with the values of the feedback resistor, see if I liked it better with some other value. Oh, and I need a 2-12 cabinet.

Thanks Pete Traynor! Thanks Canada! Thanks friends of the experimental fist!

The First-World Suffering of Infinite Possibilities

I’m lucky. I could list a massive number of ways in which I’m lucky, but this is a journal of my gear and audio projects, so I’m going to wade into the shallow end and apply this only to the pre-defined subject.

So, to start again. I’m lucky. I have a large amount of nice gear. Over the course of 20 years of playing guitar and 10 years of fiddling with amps, I’ve gathered a nice collection of stuff I’ve always wanted. I have the original Blackface Fender, restored on my own. I have numerous guitars that make my friends drool. I have plenty of effects. I have a couple extra, useful, awesome tiny amps. I have a solid bass, a rad bass preamp I built myself, and two amazing bass cabs. I have a sparkle-covered drum kit. I can get amazing sounds and ugly sounds, and cover most all of the bases.

So why can’t I just make music for a while? Why do I always go back to wanting to build something different, or re-defining my guitar setup, or trying out some new device? For instance, yesterday I went for about a two mile walk, and for most of the time I was thinking about my Cartographer amp. I realized that I was pushing towards the aesthetic and sound of Shellac’s amps. I thought I was being silly. I kept telling myself (as if I was a separate person), “You have the skill to make anything you want, to create something for yourself that works elegantly and awesomely for its purpose. What do you do? What do you make?”

I waffled between the amp I was planning in the last post, or re-working my existing gear to work for me, and then just making music. I wondered, “Do I need more stuff? Do I have a compulsion?” Like I’ve said, I admire bands who pick their palette and then stick to it. I really don’t want to acquire stuff for the sake of having stuff. In fact, I often have the urge to purge my gear.

Well, if I have to answer myself, I give the answer “Gear is Fun.” For instance, I don’t actually use one of my Fuzzy Bunny pedals in any of my bands, but I think it’s a neat pedal, and I enjoy building them and selling them to my friends. Just like when some bands form and dream about their costumes or playing the big hall in town, I dream about what gear I’ll be using, and what sounds I can make with my pre-defined gear. The problem though is that I usually have the means to make it happen, so I start the project and my time and resources get stretched more and more thin. I’ve not played guitar with another person since the last Cartographer show, and the next GvsG practice is not ’til mid December, yet I’ve spent a large amount of time contemplating my guitar gear.

I don’t know where I’m going with this. I just feel silly. I feel silly for being confused by what I want to use, and I feel silly for caring so much, and I feel silly for not being as grateful as I am for what I do own. A big part of making the pedals is knowing that people think it’s cool to own something that I built. There is an element of ego to it, as well as an element of wanting to be the guy who helps his friends get what they want. I just have this picture of my head of being on stage with my weirdo amp which I conceived and built, playing insane music, and generally seeming awesome or confusing.

So how do I get there? What is the first step? What really matters, and what is just bullshit?

The Cartographer – Proof of concept.

A short bit ago I cobbled together a guitar amp setup for Cartographer which resembled the ideas I had in my head.
Cartographer Test Amp

The 1-15 and rack gear is the same setup I used for bass in Replicator, but I’m only using one cabinet instead of two, and I’m only using one channel of the power amp instead of both in bridged mono. The blue bass preamp is a circuit I built based on a Fender Blackface guitar channel.

The top amp is a 6 watt kit called the Hi-Octane from AX84. It’s based on the JCM 800 preamp, but has a 6 watt, single EL84 power section. I got the kit, poorly assembled into this crappy practice amp case, oscillating and broke, for dirt cheap. I re-did it from the ground up, and it’s a little shred machine. Not that I NEED a shred machine, but it did get a surprising amount of use on the new GvsG record.

So I’m running into the Hi-Octane and the running the speaker out into a dummy load/speaker soak that I built a while back for my Champ. Out of the speaker soak I’m running into the other channel of the solid state power amp, and then into the 2-12 w/ tweeter bass cab I borrowed.

As an aside, I have no problem with solid state. Yes, I’m mainly a tube guy, and yes, I think for more subtle and complex music, tube amps generally sound better on guitar. However for non-subtle, assaulting, harsh, annoying weirdo music, which is what Cartographer plays, I think solid state can work just fine.

So in short, the results of the test were a big, “Hell Yes!” I’m 90% there. I did have a couple big issues.

1. I wanted a little more gain out of the bass side. Sure, I could put a gain/level boost pedal in front of just that side, but if I’m building a rig from the ground up, I may as well just give myself the option of more gain.

2. The distortion/guitar side just didn’t have the same kind of attack that my Bunnydrive into my Fender Pro Reverb has. I might be able to attain more dynamics by hitting the power amp less hard. I gave up because the borrowed 2-12 cab sounded weird. The internal crossover rolled off the highs for the 2-12 speakers. I liked having the tweeter on just a touch, but then I could still tell the speakers were too muddy.

So this was enough to keep going, and to encourage me to try the solid state simulacrum preamp of my potential full tube amp which I spoke about in the previous entry.