Archive for March, 2014

Colorless writings, part 9 – The Switcheroo

Monday, March 31st, 2014

Back on the subject of bypass switching are we?

Partially yes. But i think i’d like to say thing or two more about switches in general. Actually. I was sitting on my desk that i use as work bench and killing myself with a build. That’s when the title of today’s Colorless Writings came to me.

As i personally hand-wire everything in my builds, i only use switches with solder lugs. In the time i’ve built and repaired pedals, i must have soldered on way more than 600 switches altogether by today. At first, these mechanical components seem solid. But if you take a closer look of how those are made, you might convince yourself that the first impression isn’t as accurate as you thought.The pins/lugs are held in with plastic housing. Now, those may seem sturdy enough, but when you’re soldering your wires to those lugs and apply just a little too much heat and pressure, you can see and feel the lug moving. Once the lug moves a fraction of a millimetre, the structural integrity is compromised. In a sense, those components are probably the most fragile thing in any build. I don’t want to think how many semiconductors i’ve soldered on in all this time, but never burned any transistors by accident (yet). But have i burned switches? Many. And if we count the ones that have landed back on my desk with them becoming faulty after six months of use, there are a few more. Someone on the mighty interwebs said that firm, decisive and quick is the way to go with all the switches. I couldn’t agree more.

How do the switches work?

The most common toggle and stomp switches we use for pedals are SPST, SPDT, DPDT and 3PDT (of course there are others as well…). Next you might ask what do these initialisms mean. Well:

  • SPST – Single Pole Single Throw
  • SPDT – Single Pole Double Throw
  • DPDT – Dual Pole Double Throw
  • 3PDT – Triple Pole Double Throw

As you might have guessed, the SP/DP/3P part means how many vertical poles the switch has. The second part tells us the effective “throws”, or positions. This may be a bit misleading, since there are different ways the toggle connects the lugs. First, the SPST has only two lugs. The other position has these two lugs connected and the other has them apart. Simple, right? But then we get to the SPDT which has three lugs. There are two different toggle types of this switch. On-On and On-Off-On. Meaning that there’s actually three effective throws on the On-Off-On switch. One position connects the middle lug to the upper lug, other connects the middle lug to the lower lug. Middle position connects nothing to nothing. The DPDT has six lugs and those work exactly like the lugs on the SPDT, except that there are two vertical poles that both respond to the same flick of that switch. Same thing with 3PDT. The nine lugs represent three different poles that all connect or disconnect the same way as SPDT. There are just three of those vertical poles connecting and disconnecting at the same time. 4PDT has four poles, but those too act in the same way. Different poles can be used to connect and disconnect different things on a circuit – for a single flick. I’ve drawn a memory guide for myself a long time ago. It also includes the pot lug numbering convention that i’ve adopted for my use.

Other types of switches you might find on a pedal are tactile or momentary switches, rotary switches and possibly On-On-On types.

The tactile and or momentary switches are very common and usually used in electronic bypass switching circuitry. These come usually in two different configurations. Namely NO and NC. These mean that there is always only one “pole” that is either connected or unconnected when the button isn’t pressed. NO is short for Normally Open (not connected) and NC is short for Normally Closed (connected). Now, when you push a button that is NO, the connection is made for the time you are pushing the button. Once you release your hold, the connection is gone. Momentary switches come in all the variation of different numbers of poles with usual On-On configuration. I haven’t seen this kind of switches on pedals, since the circuitry behind the 3PDT momentary switch is usually complex – unless it is used for momentary feedback or mute control.

The rotary switches are fun. These come in many, many different configurations. For example, 2P6T and 4P12T. First part of the type “code” is for the number of poles. Usual number of poles are one, two and four. Second part tells us how many positions the pole can have. 6T is for six turns and 12T is for 12 turns. Common boutique use for these switches is to place different cap values or different clipping diode arrangements on the turns. For the cap value switching, the simplest example would be the good ‘ol Rangemaster with 1P6T switch. On that configuration, the input of the circuit should be placed on the middle pin. Then the board should have six different values for the input cap. Let’s say 4n7, 10n, 22n, 47n, 120n and 470n. All those caps need to have the other lead at the transistor’s base, while the other leads connect to the six lugs on the switch. This way the Rangemaster can be used from treble booster to bassy wide range booster and everything in the middle. There are, of course, numerous different pole and turn variations of these switches available.

The one type that’s quite rarely used in a pedal is the DPDT On-On-On switch. There are exceptions. You may have come across one of these switches in your time. Most Les Pauls, SGs, 335s and basically any of the guitars with two humbuckers have this type of switch for the pickup selector. The up and down settings work exactly like in On-On switch, but the middle position is different. While down position connects middle lugs to the upper lugs and up position connects the middle lugs to lower lugs, the middle position has fthe first pole’s middle lug connected to upper lug and the second pole’s middle lug is connected to lower lug. This gives out even more switching options than the previous types.

Yamaha MBD-20M Multiband Distortion

Saturday, March 29th, 2014

Yamaha-MBD20MII

What is it?
Yamaha MBD-20M Multiband Distortion. Made in japan around mid 80’s.

Got this unit from a guitar guru J. Lindén some months ago. He was selling the unit for a very decent price and i almost did let it go. We were at some gig back then and he said to me that “you’re stupid if you don’t take it”. So i did. Reason i wasn’t too interested on the unit at first was the non-uniform size of the pedal. I do dig those Yamaha 10MII-series pedals quite a lot, but this one has a lot wider footprint than the other pedals in the series. But am i glad i got it? Yes.

Yamaha-MBD20MII-guts1

As most of the 80’s japanese pedals, there is nothing negative i can say about the design or the board. As usual with the Yamaha pedals, the quality of soldering and box design is very nice to say at least. I couldn’t find a schematic for the circuit, but There is some information about the box on Effectsfreak.com. Apparently, the design has two separate distortions on board. One distorting the lower frequencies and the other for highs. There are two Panasonic AN6555 low noise dual op-amps to give out the gain.

Yamaha-MBD20MII-guts2

The circuit is spread on two separate boards. One for main switching and the other for the controls and a bit more.. The controls are your average distortion box controls, “Out Level”, “Distortion” and “Tone”. With addition of “Balance” which mixes the low and high distortion bands together. There are obious reasons for why the world needs a distortion with blended bands. First of all the low and high frequecies clip differently. So pushing all of the audible 20Hz – 20KHz frequencies through the harmonic clipping diodes witll result in some parts of the range clipping better the others. This is highly affected by the types of diodes used.

Yamaha-MBD20MII-guts3

Even thought the idea of multiband clipping/distortion isn’t offering a huge wow factor, it is still quite ingenious. And of all the pedals i’ve dealt with – this is rather unique method of controlling how the distortion affects the guitar’s signal. Should it be unique? I think not. It is a very good idea and it probably should be used more on the boutique world.

How does it sound?
At first the feeling on the sound is quite baffling. Only thing i count as a plus is the definition and clarity. But more i play with the box the more it gives out. Level, Dist and Tone controls are your standard bread, offering nothing too interesting. Just sufficient output level and and good range on the Tone. The distortion control goes from high gain distortion to higher gain distortion and i wouldn’t call the minimum setting an overdrive anytime soon.

Then we come to the Balance control. From muddy low band distortion to clear, open wide band distortion to cutting high mids/high distortion. Versatility is enough for many purposes from sort of emulating JCM800 driven over limits for rhythm parts and the screeching high gain lead sounds that are able to cut temepered glass.

It does sound good.

Ibanez DDL Delay

Wednesday, March 26th, 2014

DDL

What is it?
Ibanez DDL Digital Delay from Master series, made in japan in mid 80’s.

One of these units that usually are way too pricey for me. But if someone is really selling his/hers and is willing to give it away for good price, i’m once again there to snatch it. I even got a very nice present in the same parcel with this, but more about that later. Anyway. Thanks to Ari!.

I believe this unit was Ibanez/Maxon’s attempt to kill Boss DD2/DD3. The functionality matches, and the competition for king of digital delays was heating up in 1985. DDL has two different delay time ranges on a switch, plus “hold” mode. Which is similar to one found in Boss DD3 (which was in fact a rebranded DD2, but that is a subject for another pedal post).

The board is full. And when i say full, i really mean it. Neat and tiny solder joints right next to each other. And plenty of them. The MC4101F is mounted on the bottom and is responsible for all the action.

DDL-guts1

Couldn’t help myself but take another shot of the chip itself. That’ll also let you cloesr to the real scale that those solder spots have. If i was amazed what the Maxon engineers did with DFL, the digital flanger from this same series, i’m even more impressed now.

DDL-guts2

The board shares some qualities with the DFL. The three trimmers are in the same spot as is the DA/AD converter chip, the MC4101F. Couldn’t find a schematic for this right of the bat, so i can’t be 100 percent sure. It does seem like the two share some parts of the design.

DDL-guts3

The controls on this design are very impressive. There’s user’s manual scans available at Ibanez pedal information heaven, the Tone Home. Quite interesting read. They have listed the maximum delay time wrong though. It is in fact 1800ms and not 900ms.

How does it sound?
True delay monster with massive, yet clean delay times. Where the Boss’ counterpart is unnatural and cold, this massive design happens to capture some of the beauty found from analog delays. Not as clinical as you’d expect from a 80’s digital delay. Some circuits may have been scorched by time, but this sound stays unaffected. It still sounds good and fresh, even if it has about 30 years of life behind it. Very usable with its two delay time ranges and the hold mode. No wonder you won’t find any of these for cheap.

Danelectro DJ-2 T-Bone Distortion

Sunday, March 23rd, 2014

DJ2-TBone

What is it?
Danelectro DJ-2 T-Bone Distortion from Dano mini series in tiny plastic enclosure. Made in china around 2007 (dating based on a guess).

As i got accustomed to praising the mini series boxes, i thought it was a nice deal to take this home from local music shop as a new unit. Price was pretty much the same as the shop had paid for the unit when they bought it in – a.k.a. cheap. I couldn’t find a schematic for the circuit, so one of my thoughts was to rip it immediately open and see if it was just a simple Dist+/250 adaptation with standard Dano electronic switching. Taking the bottom plate off showed me the in/out board. Minis can be split into two categories when it comes to build quality. First is neat and well soldered. This category usually applies to the units with through-hole components (not always). And the second. The ones that were build on the first day of work after drinking for two weeks on chinese new year. This unit. Sinks definitely to the latter category.

DJ2-TBone-guts1

But i continued with the same profound enthusiasm that i usually have for the unexplored units. Taking the in/out board out made me want to put the little bastard back together as fast as possible. So there’s a 14 pin SOP quad opamp on two-sided, horribly made board that mixes SMD and through-hole components together. At this point i just reassembled the thing. I simply don’t want to know more about it.

DJ2-TBone-guts2

So. For those who have been following my puny blog, even though i may have sounded like it in the past – not all mini series effects are worth the trouble, money or anything else. This unit proves the point. It is probably the suckiest unit in the whole series. The sound and feel of DJ-1 Pastrami mini overdrive did let me have faith on this one too. Faith misplaced so far that a shovel won’t be enough to unground it.

How does it sound?
Like an unwanted, disfigured son of MXR Distortion III and Morley Just Distortion. Yes. Both of the mentioned are really bad sounding designs, so you can only imagine what this sounds like. Bad mid-honk, broken sounding clippers and thin overall feel. As a positive side, the  output level is sufficient for a distortion unit. But no. I have nothing good to say about this. Nor will i even think about tracing and fixing the design flaws on this one. Reason – it will most likely not be worth it. Anyone with an internet connection should be able to find hundreds of schematics that can be tweaked to perfection. At the moment, this doesn’t even wake up the explorer and tweaker in me.

So i put the plastic bag back on and stuff the thing back inside the cardboard box. Let’s see if it sounds better after getting ten or more years of cupboard treatment. I’m certain that the treatment has worked on many designs before. So there is a tiny, remote chance that it could work here too.

Danelectro DSR-1 Spring King

Thursday, March 20th, 2014

DSR1-SpringKing

What is it?
Danelectro DSR-1 Spring King spring reverb. Made in china around 1998.

Pedals using real spring tanks inside them seem to be quite rare. There are tons of different digital variations that try to emulate the original spring sound from many brands around. The biggest reason for the absence of springs inside any pedals must be the size. The length of the springs affect their sound and anything shorter than 20cm will most likely be too short of a reverb. So this time i wasn’t surprised that the circuit board itself was quite small inside the massive box. And it is with all SMD construction. Taking a closer look at the SMD ICs, there’s a PT2399 digital delay/echo chip in there. So, to compensate the shortish spring length, the design is a hybrid – utilizing a digital delay chip to get clear slap back effect in addition to analog spring sound. The three controls take care of the attenuating and slight boosting overall sound with the Volume control. The Tone seems to boost highs when maxed and the Reverb is a mixer control that blends the digital chip and the spring unit with the signal.

DSR1-SpringKing-guts1

If i wouldn’t have taken a look at the chips, i would have expected this to be all analog design. So the overall “meh” was a bit of a letdown. Nevertheless, it is a good and clever design. And it does have the springs in there, which do affect the reverbed sound. But no. It is not 100% analog spring reverb. The springs are Accutronics/Belton BS3AB2C1E, a “tank” with three springs.

DSR1-SpringKing-guts2

There’s also one more, very cool, but simple feature. The kick pad. While it’s not connected to anything, it’s simply a rubber pad glued on the top of the enclosure. Kicking it or stomping on it makes the box naturally shake. Which leads to the tank shaking and giving out the uncontrollable spring action – like heard on many surf records. Nice feature in addition to quite unique and, like i already said, clever design.

Modding the PT2399 part for fully controllable delay in addition to springs should be doable. But. I think i’ll keep the unit as it is.

How does it sound?
Good. Very good. At first i would not have noticed the digital delay that was present. So i was already patting myself on the back for an amazing deal of the analog spring reverb pedal. So the disappointment may be biasing me a bit. Without that fact i would have probably declared this unit the greatest sounding gift from the Danelectro catalog ever produced. But that aside, the sound is definitely wet enough and the controls are sufficient. Very nice, big box.

Nux OD-3 Overdrive

Monday, March 17th, 2014

Nux-OD3-1

What is it?
Nux OD-3 Overdrive. Super cheap thing, made in china 2013.

The next one of the Nux analog series box to arrive. As usual, i opened the box, tried it out and ripped it open to take a few (poor) photos. Short testing convinced me that this is nothing more than Yet Another Tube Screamer (TM).

Nux-OD3-2

Some flux residue. The box design is the same as in all the others in Nux’s analog series. The pot feel is as terrible as in others too. The pot tapers and values look familiar.

Nux-OD3-3

Taking a closer look at the heart of the circuit confirms it even further. JRC4558 and SOT packaged Si-diodes. I’ve seen that before now haven’t i…

Nux-OD3-4

Still, a reasonable build quality with solid design choices. True bypassed basic pedal. I really just wish they would do something about the pots. I don’t think the better ones with sturdier feel ans more solid build quality would have cost that many cents more per piece.

Nux-OD3-5

How does it sound?
Exactly like every tubescreamer and derivative around (mid-honk, lowish output etc.). Not much more to say. Exact circuit copy will sound like the original. No surprises there. Cheap and built with reasonable quality. Might be a nice option for anyone looking for a cheap TS with a true bypass.

Ibanez DL10 Delay

Friday, March 14th, 2014

DL10

What is it?
Ibanez DL10 Digital Delay from Power series. Made in japan between 1986-1989.

The Ibanez delays are usually highly praised and for a reason. Solid construction and nice design. When i think of it, many other types have design flaws. This of course isn’t limited to just Ibanez. Still. usable delays are more common than, for example, usable distortions. The design here seems to be pretty much the same as found on DL5, or, we could once again argue that DL5 is just a remake of this unit. Opening the standard 10-serie box shows a couple of components mounted on the solder side of the board. This always makes me a little suspicious. This time, i think the components are there by the manufacturing process. I reached this conclusion by having obtained a second DL10 in defunct state. Or it would be highly unlikely that two separate units (one bought from canada and the other from a local guitarist) have the exactly same mod performed on them.

DL10-guts1

Hand drawn acid trip traces always make me smile. This time there’s another vow-factor due to crowded digital board and the hand drawn traces. Heart of the delay circuitry is Mitsubishi M50195P, which is one of the standard echo family chips Ibanez has used on most of their delay circuits. Including Master series Flanger and a lot of others.

DL10-guts2

Good delay pedal needs to be  simple to use and still offer more controls than just one tone. The Power series delays are all pretty good items. This one is more of a simple standard, while the others offer more and more special features. Let’s face it. Maxon designers have had their spoons flying pretty high in the 80’s. After all, there are seven different delay designs in a series which was manufactured from 1986 to 1989.

How does it sound?
Like a very nice delay with reasonably good control range. This stretches from tight slap back to neverending feedback with nice long delay time. This unit is common and lots of people are still using it for a good reason. Usable. Not much more to add.

Ibanez MS10 Metal Charger

Wednesday, March 12th, 2014

MS10

What is it?
Ibanez MS10 Metal Charger from Power series. Made in japan between 1986-89.

Apparently, these units were a big seller. Which is once again something that i find intriguing. How does a very average distortion design with obvious fault in it become a big seller? I really do not know the answer to that question. Do you?

The fault i’m talking about is the low output level, which doesn’t rise above unity even with both, Level and Gain controls maxed. Gladly, this fault can be addressed with relative ease, as i’ve done with my unit. I do feel quite sad about that, as most people tend to think this is a collectible unit and so it’s ok to keep asking near astronomical prices for very common Power series box – with a built-in fault. No question about it. If i come across another unit in decent condition, and more importantly, for a reasonable price, i’ll grab it.

MS10-guts

One of the dullest board designs in the series. The circuit design is quite complex with couple of separate clipping stages. As you can see from the photo above, i’ve removed one of the hard clipping stages to get the overall level up. Also swapping/upping one of the caps from the tone section is a thing i recommend. That way you can get more bass in addition to standard Ibanez mid-hump.

For some reason i’m missing the component side photo of this unit. I wouldn’t be bothered. The SML from Master series uses the same board.

How does it sound?
To me. Not much like anything. The more bass and omitted one clipping section do make it a lot better, but still it is nothing more than mild distortion driver. With the mods the overall tone is a lot more overdrivish than anything that i’d associate with a “metal” distortion. Stock unit works the best with a high gainer tube head – when pushed into the drive channel. Modded one works well as a standalone overdrive too. Not the worst distortion pedal there is, but definitely not among the best either.

Despite everything. I’d recommend the mods.

Electro Harmonix Ego Microphone Booster

Sunday, March 9th, 2014

Guess i haven’t been this deep into producing vintage pedal porn before…

EHX-Ego

What is it?
Electro Harmonix Ego Microphone Booster. Made in US around 1969, according to pot labels.

Got this unit as a defunct gift from J. Stolpe of Väinö Grön (and numerous other bands/musical outfits). Story is the he found this unit from his father’s belongings and kept it. As we got into talks about my favourite subject in the world, he just decided to give it to me. The signal was passing on “bypass” mode and when the battery was connected and the boost engaged it acted as a dirty buffer. After looking into the design, it became clear that the design is 1:1 with all the original LPB-1s and 2s. All it takes to create a one transistor boost is an input cap, two resistors from supply to base and base to ground (these two form a bias voltage for the transistor), gain setting resistor from emitter to ground and a resistor from supply to the collector. Oh. And a output cap. Boost control is your standard 100K pot (output cap to lug 3, lug 1 to ground and lug 2 is your output). By the way, Beavisaudio has a perfect one paged article/image about how the single transistor booster works. If you’re not familiar with the subject, check it out here.

EHX-Ego-guts

The fault in this unit was with the resistor from transistor emitter to ground. It was completely burned out and cut in two. Looked like someone had already tried to fix it with not so great results. I was afraid that the 36999 branded transistor was dead due to the heat. Those transistors are  apparently Fairchild made clones of 2N5088, that they manufactured for EHX in late 60s. I have no way of verifying this information, but it was on the internet, so it *must* be true.

Anyway. The burned resistor seemed like 330R in value, so i went through all my boxes and drawers for similar carbon composition resistor to match the original. Nope. I didn’t have any. So i just fixed it, no matter of the cost. As you can see in the photo above, there’s one resistor that doesn’t quite match the others. I used the standard 1/6W 1% metal film resistor in its place. Works. And even the original transistor works perfectly!

Then i thought to myself, “what makes this a microphone booster, as the circuit is 1:1 with Linear Power Booster?” The jacks. That must be it. The LPB has the other end as a plug – you know, to be used with a guitar. If there are two jacks, then it must be for the microphone. Damn i just love vintage stuff like this!

How does it sound?
Exactly like the linear power booster(s). Clean and loudish  to the ~90% of the knob sweep. And then badly distorting at the end. The circuit keeps the frequencies well in tact while the line driving capabilities are worth a mention. Not great thing, but very cool little tool to have. In fact, i’d recommend every guitarist to use one of the LPB-1s in their lifetime. It should at least open ones eyes to the idea behind loud “clean” boosters.

Boss RV-2 Digital Reverb

Friday, March 7th, 2014

Boss-RV2

What is it?
Boss RV-2 Digital Reverb. Made in japan, 1987.

Got the unit in a bag of crap i bought from one local guy. The unit was missing a bottom plate altogether and it was not in working condition. Checked the insides around for a while and there were just couple of loose wires coming from the jacks to the board. Soldered those back to their places and got it running. The missing bottom plate was another issue. Where was i to acquire a grey label Boss bottom plate? Nowhere. But i had an old japanese DD-3 with burned chip in a  spare parts box, so i scavenged the plate from that one. It is with blue label and from around 1988, so it’s not the closest possible match, but it’ll have to suffice.

This is likely to be the very first digital reverb in a compact pedal form ever. With all the features of professional rack mount units included, it’s bound to be quite complex design.

Boss-RV2-guts1

I may have written about filled boards before, but this one takes the grand price. The boards are made with tiniest SMD-components and the design still had no  chance of fitting in a standard Boss enclosure. Didn’t notice it at first. But yes. The box is slightly taller than the standard boxes. Apparently, the taller box is used only in PSM-5 and RV-2. PSM-5 needs the taller box because of the jacks at where the knobs normally are. This one however.. Needs all the possible space to house the boards. All the other designs fit in the standard one.

These pictures do not cover the detail of two stacked boards too well, but that’s how it’s made. With two massively crowded, two-sided boards bonded together. More as a detail, even the digital chips are Boss-branded. This must have been pretty expensive thing to manufacture…

Boss-RV2-guts2

Quick googling around didn’t give out a schematic, but i’d like to see one – just to see if i could understand anything of it.. All in all, this is the most complex design in such a small enclosure i’ve ever seen. The board design has more components on it than your 90’s PC motherboard. And it’s still nothing more than a reverb unit, mimicking a full fledged rack mount monster. The features easily trump most of the modern table top units. Six modes from plate to gate, to room, to hall and panned reverbs. All with adjustable time from 0.2 to 10 seconds. Then there’s the pre-EQ control for tuning the frequency range that we want to reverberate. And mix control, of course. Overall, very controllable.

Boss-RV2-guts3

It does surprise me that the current market value of these units is not higher. First of all, these were only made in japan for less than a year and a half, from 1987 to 1988. Second, the engineering is more than just respectable. Third…

How does it sound?
It doesn’t sound bad at all. Sure, it may not last too many rounds in the same cage with high-end brand rack mounted studio reverbs.. But then again. This is just a tiny pedal from Boss’ compact series and it’s meant to be used with a guitar. As a guitar effect? Just beautiful from small ambient plate to massive, wettter-than-ever surf reverberation. Good controls, good overall feel and sound. Where some (or be exact, most) Boss compact pedals leave me with no feelings at all, this one is not one of them. It’s versatile and usable pedal. And on top of that it is an important piece of stompbox history. So.. If you have a grey label bottom plate laying around without a pedal, drop me a line…