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hammer MXR Digital Delay (Blue Rackmount) 5/6/101 2:17 pm
Although very limited in delay time by today's standards (320msec stock), this unit had a number of interesting features. Among them is an LFO which can modulate up to 1000hz, yielding some ring-modulator type sounds. The delay time can be swept with a footpedal, which can be any old thing containing a 50k pot wired up as a variable resistance to ground (you can see this in the lower left hand corner of the schematic on page 15). The unit also uses a switching scheme in which selecting a delay range also selects an optimal cutoff frequency to keep clock noise out. You can see this on the front panel (20khz, 10khz, etc.). Delay time can be extended by means of additional memory cards. These days, such memory cards - *IF* you can find them - cost about the same as a full fledged delay stompbox with more delay time. Fully stocked (4 memory cards), you can squeeze 1280msec out of the unit. In a perfect world, you could easily replace all the memory cards with probably one or two considerably lower power high density RAM chips. Trouble is, there are no numbers on these chips and I have been unable to identify their architecture. Five big ceramic chips per card, 320msec capacity per card; YOU figure it out cuz I certainly can't.

 
hammer PAiA Hyperflange 4/2/101 3:57 am
This was a terrific design, that PAiA offered in kit form for damn near a decade, until some of the core chips got so hard to find that they couldn't support it. I've included a scan of my PC board from PAiA with the 2-part article (from the now extinct Modern Recording). If you can score a Curtis CEM3340 oscillator chip and a Reticon SAD-1024, then you have just about everything you need to roll your own. Be forewarned that 3340's go for $40-50US on the open market these days. The article provides some very nice technical info about modulation and flangers in general.

 
hammer BOSS BF-1 Flanger 4/1/101 6:16 am
This is the service manual for the BOSS BF-1 Flanger pedal. Many thanks to Matt Parker from down under for sending this to me. Unlike the BF-2, this model uses the Reticon SAD-1024, allowing it to clock higher, achieve a shorter minimum delay, and a more pronounced swoop/sweep. Interesting side-note: the pedal itself indicates 9vdc on the adapter jack (it requires and adaptor and can't work from batteries), but the service manual indicates a preference for 12vdc. It sounds better with 12vdc. Wonder how many of these are sitting around second hand because owners never heard it at its best?

 
hammer PAiA Phlanger 4/1/101 5:52 am
This article from wayyyyyy back in the 70's describes one of the coolest phlangers of its era. The PAiA Phlanger, unlike its contemporaries, was voltage controllable, permitting use of things like external expression pedals, envelope followers, etc. The article contains a PC-mask but be forewarned that the scaling isn't accurate, you'll have to tweak the size to use it for PnP or something similar. Many thanks to Peter Snow for the article.

 
hammer Anderton Delay Projects 4/1/101 5:32 am
This file contains the "Pedal Flanger" project that appeared in Guitar Player in 1980, and the "Chorus-Delay" project from the same era. Both use Reticon BBD chips, and neither has a PCB pattern. My apologies for the quality of the photocopies that the scans were made from. The schematics, however, are quite legible.

 
hammer E&MM String Damper 3/31/101 4:27 pm
This is a DIY project describing an LM13600-based attack/decay unit, suitable for guitar or bass. Thanks to Mike Irwin for hanging onto this for 16 years.

 
hammer E&MM Harmony Generator 3/31/101 4:16 pm
This is an older project article describing a mono effect which will produce 3rds, fifths and unison over several octaves. Thanks to RG Keen for this one.


 
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