Posts Tagged ‘Loop’

EHX Memory Man with Hazarai XO

Wednesday, March 18th, 2015

EHX-XO-MMwHZ

What is it?
Electro Harmonix XO Stereo Memory Man with Hazarai. Made in new york in early 10’s.

Got this unit used with a defunct tag in a trade. I was sort of skeptical as most of the modern EHXs are just plain dead and there is very little that can be done. But i went for it anyway, out of curiosity. Pedal was and is in decent condition with a few marks of use. Since the old school lab supply on my desk can only put out 100mA i figured this wouldn’t the one to be tested on that supply. After checking the manual, i set up one of my old power supplies with 500mA output and tried the pedal out. Nothing. No sign of life. Oh well. These things can happen and some trades leave me on the win anyway, so getting one brick isn’t going make much of a difference. Still i wasn’t convinced. I took out my modern favourite power supply that can put out 1A if needed and tried again. Took the pedal about 20 seconds to perform its power on self tests, but this time everything seemed to be running smoothly.

EHX-XO-MMwHZ-guts1

I do recall running into similar issues with other all digital designs. If the circuit is fed with too low current, things can get weird. Seemed like the case with this one. My guess is that someone had used low current supply and this has caused the digital circuitry to act in an undesired manner. Others could still think that the unit is broken and i’m not disputing that. It’ll work just fine if it has a power supply that’s capable of satisfying its needs. The damage has been done and it’s not getting any younger. But it works.

As the photos show, there is very little us lumberjack-style effect enthusiast can do if the pedal is really dead. This is partially a sad thing as the people qualified to repair these things are scarce when compared to old through hole manufacturing methods. Meaning that there will number of units that will get trashed due to not being cheap or viable enough to repair when something goes wrong. One of the biggest culprits of modern times. Unsustainability.

EHX-XO-MMwHZ-guts2

In heart of it all lies an digital signal processor manufactured by Analog Devices. Yup. I’d call that an oxymoron. Although AD chips and processors are top notch and those tend to be used for many audio applications. This design is all digital and size of the chip tells us that it’ll beat your Commodore 64 in a heartbeat.

Next up i was to try the unit out, now that it was working. Five pots with a digital rotary switch and two stomps. Unit can be used as a standard delay, but that will leave a load of features out. We have our multi tap and reverse delays in addition to the expected ones. The looper function is in there too. I must admit i had to search for a user maual to get any real testing out of it. If you want an overview of the features, i suggest you do the same. It would take me quite a time to explain everything, so let’s just get on with it.

How does it sound?
Pristine. Designed in a manner that the unit could be usable with synths and organs as well as with guitars. Frequency responce doesn’t discriminate and the buffering at the beginning of the signal path doesn’t care wether you push it hard or with vintage guitar pickups. One could truly earn a cape of a wizard if one was to learn every feature and use them in a live set. Good clean tones and repeats are well controlled. This truly isn’t your average delay and i believe the designer has done his/her work by chasing the features that are not found on every single delay unit out there.

Sound good and works fine with suitable power supply. Some of the features still elope me, but that’s just me. You should try one out to see if you like it. For me, i’m a lumberjack.

Boss PSM-5 Power Supply & Master Switch

Thursday, August 14th, 2014

Boss-PSM5

What is it?
Boss PSM-5 Power Supplu & Master Switch. Made in japan, november 1982.

There has been a time place for everything. Daisy chaining, or dedicated power supplies were both practically unheard of until this new and exciting device hit the market. What surprises me more is that the pedal was actively sold from 1983 all the way until 1999. I thought the interest for the features offered would have been way gone by 1999. This unit has seen use and it has the orginal black label on its bottom. The label explains the main features as well.

Boss-PSM5-back

The nice looking old school style board houses the boss standard flip-flop switching and an effect loop (’cause that’s what the pedal actually does). These were originally shipped with a power supply and a splitter cable for up to seven effects. Since my specimen is from the year 1982, you can take a guess if either of those have survived. Quick search produced a schematic, which confirms that the design for the loop is simply four buffers, controlled by electronic switching – an effect loop if you will. Schamatic also shows that the power supply is only splitted for the out going 9VDC.

Boss-PSM5-guts1

One other thing noted in the schematic. The operational amplifiers should be NJM4558DD, or in other words the classic JRC4558D. Seeme like mine has been modded at some point in the pedal’s life. The ICs have been removed and replaced by sockets, which now have two LF353s, high grade audio chips in them. Rest of the semiconductors seen on the board are two BJTs for the flip-flop, another two BJTs for LED control and four JFETs to take care of the actual switching of the loop.

Boss-PSM5-guts2

These older Boss boards are mostly a pleasure to look at. Acid trip traces but annoying lack of symmetry. Plus an acre of free land to grow your tomatoes.

How does it sound?
It works as an effects loop, so it should not have a sound of its own. And furthermore, it doesn’t. I do understand why someone wanted to swap the opamps for “better” ones, but as they are acting only as an unity amplifiers (or we could say buffers), i strongly feel the improvement in sound is next to nothing. This being there’s not much i can say about how it sounds. It is a relic, which makes it rather interesting.

I do believe this had lots and lots of user value back in eighties and in the beginning of 90s. Using one now? Not a chance. There are tiny hardwired true bypass loopers and extremely high quality standalone buffers in existence, so at least for me, the choice would be very simple and clear.