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Thread: Castle Flanger Schematic

  1. #1
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    Castle Flanger Schematic

    I have a Castle rackmount Flanger in for repair. Passes signal but there is a problem with the sweep. Some kind of glitch that causes the delayed signal to distort at the end of the waveform.

    I've searched the web for info on this unit and can't find anything other than this was made sometime in the 80's and that Castle is long gone.

    Does anyone here have any info or a schematic for this thing? If not, I'll have to try and reverse engineer it.

  2. #2
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    I've seen this in other Flangers. The BBD was the problem. It was distorting the delayed signal and was more apparent as the signal fades out.

    Sometimes just a tweak of the BBD bias and offset pots will get rid of the distortion as well.

    Let us know what you find out.

    CJ

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    Um, this is going to sound dumb, but do you by any chance mean the Castle Phaser? I am unaware that Castle had ever produced anything other than a couple of excellent phasers. Not that I have a schematic for it, but properly identifying the actual technology might be a good start to figuring out what to look for.

    I know there are pictures of the phaser board at modezero.com, so perhaps staring at those might give some folks here a bit of a start on what to recommend.

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    Quote Originally Posted by Mark Hammer View Post
    Um, this is going to sound dumb, but do you by any chance mean the Castle Phaser? I am unaware that Castle had ever produced anything other than a couple of excellent phasers. Not that I have a schematic for it, but properly identifying the actual technology might be a good start to figuring out what to look for.
    No, this is a Flanger. Single rack space, same off white color as the phasers and same logos/graphics. Yeah, I've seen the phaser photos and reviews on line, but like I said nothing on the Flanger.

    I haven't spent too much time on this one yet, but it has some fairly sophisticated features. I've been researching the chips in the circuit, and have just found spec sheets on the SSM chips. The rest of the chips are fairly typical stuff, op-amps, compander, c-mos switch, etc.

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    Hmmm. Interesting. They made a great phaser. I'd be curious to know what sorts of features were incorporated in a flanger by those same folks.

    Just out of curiosity, what SSM chips were included? I'm guessing they might be 2040 chips?

  6. #6
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    Quote Originally Posted by Mark Hammer View Post
    Hmmm. Interesting. They made a great phaser. I'd be curious to know what sorts of features were incorporated in a flanger by those same folks.

    Just out of curiosity, what SSM chips were included? I'm guessing they might be 2040 chips?
    Mark: I haven't had much time to spend on the research of this, but I think you are right about the SSM2040 chips. I will open it up later and let you know what's inside.

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    The castle products were made when the SSM2040s were actually available and reasonably priced (heck, I bought 5 of them from a guy in Dallas for $10 at that time!). Wouldn't surprise me if they were used for filter sections.

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    Mark: I was wrong about the SSM2040 chips, it uses 2-SSM2044's. Here is a list of all the IC's in the unit.

    1-LM337
    1-LM317
    2-R5106
    1-SSM2031
    2-SSM2044
    1-NE572
    3-LM324
    1-CA3080
    1-4027
    1-4066
    5-TL072

    I have posted photos of the front, back and circuit board in my folder at ampix.

  9. #9
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    Wow! That is a really interesting complement of chips, and what seems to be as advanced a flanger design as one is likely to ever see in the analog domain. Is this a stereo design or does it have dual oscillators or something like that? Having one NE572 suggests a mono output, but having a pair of 256-stage BBDs and a pair of SSM2044 4-pole lowpass filters suggests the possibility of two semi-independent delay paths. There is also the possibility that the device does "through-zero" flanging with one R5106 set for fixed delay.

    Having an SSM2031 onboard also suggests that Castle was using a tracking filter to optimize the bandwidth/noise tradeoff. In other words, the LFO drives the SSM2031 and the SSM2044 chips at the same time. As the clock frequency goes up, so does the cutoff point of the lowpass filters. The old MXR analog delay did a similar kind of trick, except it accomplished it by dividing down the clock pulse to produce a switched-resistance variable filter, using CMOS switches. Here, I assume the circuit uses voltage-to-current convertors to feed the SSM2044s and vary their cutoff frequency.

    The more I hear about this unit, the more it intrigues me.

  10. #10
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    Quote Originally Posted by Mark Hammer View Post
    ...having a pair of 256-stage BBDs and a pair of SSM2044 4-pole lowpass filters suggests the possibility of two semi-independent delay paths.
    Yes, there is a front panel switch that selects delay I or II or I & II.

    As far as I can tell so far, mono signal path, a jack to allow outboard voltage control of sweep speed (?).

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    It's Fixed...

    Ok, I put this on the bench and went through all of the voltages, everything seemed within reason. Started scoping waveforms at different points looking for problems, again everything seemed reasonable. Controls changed freq. of osc. etc.

    While scoping the low freq. osc. chip, I had forgotten that the LM324 has power on pins 4 and 11. I found a perfect sine wave on pin 11 and dismissed it as ok until I looked up the pin out. Turned out to be a bad cap in the negative power supply.

    This thing does have two separate delay lines, one set for a longer delay, one for a shorter delay. The front panel switch allows for short only, long only and both delays at the same time in parallel. The controls allow for full adjustment to get really nice chorus and flange effects, as well as slapback echo. All with decent frequency response (until you set for longer delay times).

    Mark, before I button this thing up, is there anything you'd like to know about? If you have any questions, I'd be glad to try and answer them for you about this one.

  12. #12
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    Thanks for that kind offer.

    1) Are they BOTH R5106 chips or is one different than the other? Seems to me that a 256-stage BBD is not exactly God's gift to slapback or chorussing, even though it helps achieve the short delays needed for flanging.

    2) Any possibility of some pix? I have not found anything on-line and I imagine many folks would be every bit as interested as myself to see this puppy, and have some sense of its feature set. m If you could do any board shots, that would be heavenly.

    3) Failing pix, could you describe the control features?

  13. #13
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    Quote Originally Posted by Mark Hammer View Post
    1) Are they BOTH R5106 chips or is one different than the other? Seems to me that a 256-stage BBD is not exactly God's gift to slapback or chorussing, even though it helps achieve the short delays needed for flanging.
    They are both the same, but they are set for different delay times.

    Quote Originally Posted by Mark Hammer View Post
    2) Any possibility of some pix? I have not found anything on-line and I imagine many folks would be every bit as interested as myself to see this puppy, and have some sense of its feature set. m If you could do any board shots, that would be heavenly.
    I had mentioned before, that I had posted some photos in my folder (52 Bill) at Ampix. There is a front panel, back panel and a circuit board shot. Take a look and let me know if there is something else you want to see.

    Oh, and by the way in an earlier post I made a mistake on the chip set list, there are 4-TL072 and 1-TL071, not 5-TL072s.

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    Just looked at them. Thanks a million for that. Thanks for directing my attention to the Ampix gallery too. Hadn't looked there before. Shame on me!

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    Quote Originally Posted by Mark Hammer View Post
    Um, this is going to sound dumb, but do you by any chance mean the Castle Phaser? I am unaware that Castle had ever produced anything other than a couple of excellent phasers. Not that I have a schematic for it, but properly identifying the actual technology might be a good start to figuring out what to look for.

    I know there are pictures of the phaser board at modezero.com, so perhaps staring at those might give some folks here a bit of a start on what to recommend.
    I have a Castle Echo Chorus unit, also a rack job.

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    hello gentlemen: I have both the dual phaser rack mount and dual chorus flanger by castle, and yes they are both some of the finest sounding instruments of their kind. I lucked out and found them in a pawn shop in New Mexico while on tour with a band. My Phaser has been "dead" for almost 4 years.. won't turn on, will not light up-- and what has prevented me from getting it repaired is that no one seems to have any schematics and so (I guess, as I am not a repair person) they can have no clue as to how to proceed. Do you have any advice for me?? cuz I want that thing back in action. I bought a Mutron BiPhase, to help me ease my sorrow, and for as amazing as that one is, its not as unique and musical as the Castle! thank you..

  17. #17
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    I would suggest taking it to any repair shop that has a history of repairing older equipment. There are a number of guys here that have service shops that would be able to help you.

    When something will not power up, there are a few specific things to look for that any qualified repair person should be able to find, even without a schematic. The power supply on these units are basic analog designs with linear voltage regulators. Any tech should be able to fix this with no problem.

    Once the power supply is working, if there are any issues with obsolete chips or other parts you may have to do some creative thinking to get around this, but there is always hope.

  18. #18
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    Thank you for that very clear view, Bill. I thought that a decent repairman would be able to sleuth it out. I think the places here (Berlin) that I've taken it to have been just swamped with work, and they didnt want to do any kind of creative thinking, without the schematics to hand! Im inspired to try again!

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    Quote Originally Posted by gordonraphael View Post
    hello gentlemen: I have both the dual phaser rack mount and dual chorus flanger by castle, and yes they are both some of the finest sounding instruments of their kind. I lucked out and found them in a pawn shop in New Mexico while on tour with a band. My Phaser has been "dead" for almost 4 years.. won't turn on, will not light up-- and what has prevented me from getting it repaired is that no one seems to have any schematics and so (I guess, as I am not a repair person) they can have no clue as to how to proceed. Do you have any advice for me?? cuz I want that thing back in action. I bought a Mutron BiPhase, to help me ease my sorrow, and for as amazing as that one is, its not as unique and musical as the Castle! thank you..
    Hi. It IS possible that I have schematics for the unit I have and less possible that I have the Phaser schematics.
    Please, every so often, remind me to look...as these may be stashed away somewhere a bit difficult to get to...and, on occasion, will get up the courage to hunt and search them out!
    All the best,
    zalmo

  20. #20
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    This picture of the floor unit board provides some insights into the circuit. First, it uses OTAs (the CA3080 chips) for the eight phase shift stages, similarly to what the much simpler EHX Small Stone phaser does. Second, where the CA3094 chip in the Small Stone includes both an OTA and a buffer, the Castle design uses one half of a TL072 dual op-amp as buffer, to compensate for what the CA3080 lacks. Finally, you can see an NE570 chip, which is used for companding, to both manage the limited headroom of the 3080s, and to keep the signal output quiet.

    The site where I got this notes that later issues used the long-since out-of-production SSM2040 instead of the 3080s. I have no idea if the dual-rack version was concurrent with, or subsequent to, the version shown here.

    The 2040 was four OTAs on a chip, and was regularly used for 4-pole synth filters in many popular synths of the early 80's (e.g., the Prophet 5 used five of them). I will note that Roland came up with its own comparable proprietary chip in the early 80's - the IR3109 - which they also regularly used for both synth filters as well as phasers. Both the Boss PH-2 and RPH-10 used a pair of them. Though I imagine you might find some in the Akihibara in Tokyo, they are otherwise unobtainable, and in any event are not pin-for-pin compatible with the SSM2040. The late, and deeply missed, Jurgen Haible came up with an all discrete replacement for the 2040.

    But I digress. This thread is about the flanger, and not all things Castle.

    castle-iii-cx.jpg

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    gordonraphael, just like the flanger that I repaired, my guess would be that your problem is repairable. I enjoy the challenge of figuring out why things stop working.

    I for one hope that the schematics for Castle products do eventually turn up. Even though many of the chips have gone into oblivion, I'd still like to see what the designers did to make them tick.

    And Mark, I doubt that any one minds the fact that you have added your insight here. Unless you start one there will probably never be another Castle thread on this forum.

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    It's great to have more info on the Castle stuff here! I had no idea they made anything other than phasers (the Phaser III).
    Does anyone know how long they were in business?

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    Quote Originally Posted by buck1107 View Post
    It's great to have more info on the Castle stuff here! I had no idea they made anything other than phasers (the Phaser III).
    Does anyone know how long they were in business?
    Welcome to the place. I don't know, but I guess I remember seeing the ads for the phasers for at least 2-3 years. Maybe Mark Hammer has some better information in his files.

    Do you own any of their products?

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    Quote Originally Posted by 52 Bill View Post
    Welcome to the place. I don't know, but I guess I remember seeing the ads for the phasers for at least 2-3 years. Maybe Mark Hammer has some better information in his files.

    Do you own any of their products?
    Thanks for your post.
    No, I don't currently own any, but it's been a nearly life-long quest, beginning with receiving their then-new catalog back in June 1981.

    Any information would be welcomed.

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    Smile

    Quote Originally Posted by gordonraphael View Post
    hello gentlemen: I have both the dual phaser rack mount and dual chorus flanger by castle, and yes they are both some of the finest sounding instruments of their kind. I lucked out and found them in a pawn shop in New Mexico while on tour with a band. My Phaser has been "dead" for almost 4 years.. won't turn on, will not light up-- and what has prevented me from getting it repaired is that no one seems to have any schematics and so (I guess, as I am not a repair person) they can have no clue as to how to proceed. Do you have any advice for me?? cuz I want that thing back in action. I bought a Mutron BiPhase, to help me ease my sorrow, and for as amazing as that one is, its not as unique and musical as the Castle! thank you..
    Hi! It's great to hear from a Castle fan. I might be able to help you with this, if you're still looking to get your Dual Phaser III repaired.

  26. #26
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    There was also a Chorus Echo unit which about a dozen were made....which I happen to have one, owned by Mickey Lee Lane, Top 40 Rocker.
    I plugged it in and it still works.
    Who knows the last time this unit got to eat some electricity?

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