# Looking to have a Hartman Flanger repaired - Fixed by bduguay!



## CMCRAWFORD (Mar 17, 2014)

Just purchased a Hartman Flanger from a from a seller in the US and it seemed to arrive in one piece based on the packaging but it is not working. I am in touch with the seller but because of the cost of shipping back to the US, plus the fact I was hit with a $52 customs charge to receive it, we are looking at the possibility of having it repaired locally. At the very least, have someone take a look to see if they could find a root cause of the issue.

The pedal will allow a dry by pass signal but as soon as you engage the pedal the sound cuts out and there is no sign of the effect at all. This was tested with a 9V pedal power supply and a 9v battery. I also tried 12v which is fine according to the info sheet that came with the pedal. 

Here is a video I took for the seller and shortly after taking this video the light will not turn on when the pedal is engaged anymore. 

http://vid1350.photobucket.com/albums/p778/Chrismcrawford/Hartman Flanger_zpszhxl3fqe.mp4

I am located in Whitby, Ontario. Not sure if there are any techs local (or not local) who could repair this or should I just cut my loses and return it to the seller?

Thanks in advance!

Chris


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## mhammer (Nov 30, 2007)

We are driving through Whitby up Thickson Rd. to Highway 12 to Orillia on the 12th, and driving back through on the 15th. It's a trip to the in-laws, and having something interesting to do while I'm there would be nice.

If you can wait that long, and feel like you can trust me, I can bring some tools up with me, pick it up, take a peek at it, and return it to you on the trip back. If I was on my own, I'd offer to stay and repair it, but my wife and son would like to get going.

Best case scenario, I fix it. Worst case scenario, I'm able to tell you it's not this or that, and likely X, so that you can minimize bench-time at a real repair shop.
We can correspond off-line. If you could send a pic of the insides, and let me know if there are any particular screwdriver requirements, that'd be good. I gather I am correct in assuming it attempts to be a faithful recreation of an early Electric Mistress, at least in terms of controls?

Do you have a meter of some kind? Perhaps you could do some preliminary tests. For instance, do we know that there is continuity in the stompswitch? It can often happen that people overheat stompswitches when installing them, liquefying the damping grease inside, which turns into an insulator on the contacts when it cools. (see: 



 )

Do all connections between the jacks and PCB seem to be okay? Has anything lifted up on the board? And so on.


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## CMCRAWFORD (Mar 17, 2014)

Thanks very much for the response. I have heard back from Brian/BDuguay and have had work done by him in the past but lost his contact info. It is off to him tomorrow to see if it is repairable. If not, the seller is totally stepping up and offering a full refund if not and will cover any repair costs.


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## mhammer (Nov 30, 2007)

If I'm notmistaken, Brian was using a Deluxe Electrc Mistress for a while during his band days, so he probably has a good handle on what to look for.


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## bduguay (Jul 15, 2009)

Problem found and solved....mostly.
There was a 10ohm resistor in the power section that was burnt to a crisp. I swapped it out and the pedal is working but the replacement is very hot to the touch. Nothing else seems funky though.
Thoughts Mark?
B.


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## bduguay (Jul 15, 2009)

It seems this resistor is meant to drop 9vdc down to 7vdc for the 4046 chip.


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## sulphur (Jun 2, 2011)

Would looking at another one help, or even some gut shots?

I could ship it out to you, or get some shots if it would do any good.
I have one here that worked the last time that I used it.


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## bduguay (Jul 15, 2009)

That's a mighty kind offer but I think if you were to pop yours open, power it up and check to see if yours gets hot to, that would help out tremendously without having to ship it.
Thanks!
B.


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## sulphur (Jun 2, 2011)

@bduguay Was that resistor in the R2 position on the board?


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## mhammer (Nov 30, 2007)

bduguay said:


> Problem found and solved....mostly.
> There was a 10ohm resistor in the power section that was burnt to a crisp. I swapped it out and the pedal is working but the replacement is very hot to the touch. Nothing else seems funky though.
> Thoughts Mark?
> B.


Should I assume you are referring to the Hartman flanger? Looking at gutshots, and the schematic for the DEM, the Hartman appears to be essentially an adaptation of a Reticon-based flanger to a Matsushita/Panasonic platform, with the addition of a 4049-based buffer to give some addition current oomph to the clock signal so it can overcome the inherent input capacitance of the MN3007 and accept much higher clock frequencies.

The SAD1024 had a much lower input capacitance on the clock pins, so you could feed it clock pulses well in excess of 100khz without having them turned from square to trapezoidal or triangle. The MN3007 had much higher capacitance on those same pins. Normally, it would be quite comfortably driven by its companion MN3101 clock chip, but the datasheets indicate that you shouldn't aim for more than 100khz max freq. That limitation is what made the Boss BF-2, and so many similar designs, less inspiraing as flangers. They simply couldn't achieve delays much shorter than 1msec, because of the clock freq limit, because of the input capacitance, because of the absence of something to goose the current of the clock-chip output. The Reticon could handle 1mhz clocks without any outside help, which is why many of the most desirable flangers would use the Reticon chip.

However...I'm not seeing a 4046 chip on the board. Did you mean to write 4049, or are you referring to something entirely different?


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## CMCRAWFORD (Mar 17, 2014)

I think this is very cool you are all offering technical input on this issue. I have no idea what you are talking about but I really appreciate it all the same.


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## mhammer (Nov 30, 2007)

It's actually more comprehensible than you'd think...when the $50 words are removed.

The delay chip takes a succession of samples, right? It takes those samples in alternating fashion and passes them along. The faster they are taken and passed along, the shorter the delay time. The clock generator provides a tick and a tock. When it's tick the sample is being taken and stored. When it's tock, the sample is being passed on to the next stage. Two parallel paths inside the chip are busy taking samples and passing them along in alternating fashion such that when one is sampling, the other is passing, and vice versa. The two paths then get stitched together at the output so that there is a continuous seamless stream of samples. It's a little "stair-steppy", but some filtering fixes that and crerates theillusion that it's just like a continuous analog signal rather than a sampled one.

The clock "instructs" the chip to take the sample or pass it along. The immediacy of the chip's response to that "instruction" requires that the clock pulse occur immediately, rather than gradually. That is, the clock pulse hitting the delay chip has to be square, rising sharply and falling just as sharply. Since there is a threshold voltage that the clock pulse has to reach for the delay chip to do its thing, you do NOT want the clock pulse to rise gradually, in triangular form, since that means there will be short gaps between the taking of each sample. It's like the clock generator instructing the delay chipto take a sample.....nnnnnnnnnnnnnnnOW, and pass it along nnnnnnnnnnnnnnnnnOW! The audio quality will be terrible.

The pins where the clock pulses are fed on the delay chip act like treble cut, except REALLY high up. So, the same way your guitar tone control has no impact on bass frequencies, the "treble cut" on the clock input pins has no impact if the clock rate is under 100khz, but starts to "roll off the treble" and round off those nice square clock pulses when the clock rate exceeds that, with the resulting decline in audio quality.

HOWEVER....that is only true if the clock generator circuit is the MN3101 or MN3102 chip Matsushita/Panasonic designed to make delay circuits easy and small to build. It can provide enough "drive" for the pulse to remain unaffected and perfectly square, but craps out in that regard above 100khz. If one adds some drive and buffering, then the delay chip will happily be "clockable" at rates/speeds much higher than 100khz.

The now out-of-production Reticon SAD1024, that was used in the DEM and so many other pedals, was designed such that it introduced much less "treble cut" on those clock input pins. How much less? Roughly 1/7th, such that you could feed it 700khz without any outside assistance, and achieve REALLY short delays. The truly great flangers will sweep down to under 0.2msec. I know it may not seem like much to go down to a fifth of a millisecond from 1msec, but trust me, you *hear* it. Dramatic flange sweeps need a sweep range of at least 20:1, and more often at least 30:1. A 20:1 sweep that starts from 1msec, would go from 1-20msec, and delays beyond 15msec tend to yield chorus effects not the "notch infestation" that great flanging provides. So if one wants a big sweep ratio, but doesn't want to crossover into chorus territory, you HAVE to start low and that requires a very high clock frequency and a chip that can handle it. Sweeps from 0.2msec to 10msec have a 50:1 ratio, and stay well within flanging range. I mention this to emphasize why folks make a big deal of Reticon chips and pedals that use them.

HOWEVER....it is possible to clock Matsushita/Panasonic chips like the MN3007 really fast as well. I've heard one clocked well above 1mhz, and the flange effect sounded like it descended from the stratosphere. Companies like A/DA learned that if you provided the extra drive to the clock signal, it reached the clock pins on the delay chip unscathed. That's one of the reasons why the old A/DA Flanger soundedso magnificant; it was able to successfully clock REALLY high, and achieve ultra-short delays.

In a way, it is a bit like the effect of an onboard preamp or buffer on a guitar when the signal has to travel long distances. In the absence of buffering, the capacitance of the cable shaves off high end. But, buffer the signal and add some drive, and it can travel great distances unscathed. The 4049 chip on the Hartman is used to provide that buffering and extra drive so that the MN3007 can be made to sweep down to uber-short delay times.

There, does that make sense?


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## CMCRAWFORD (Mar 17, 2014)

It does, thank you!


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## bduguay (Jul 15, 2009)

sulphur said:


> @bduguay Was that resistor in the R2 position on the board?


This board is not labelled but I can tell you it's the first resistor directly to the right of the 220uf electrolytic cap. It should be marked with a brown, black, black, gold, brown bands.
B.


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## bduguay (Jul 15, 2009)

mhammer said:


> Should I assume you are referring to the Hartman flanger? Looking at gutshots, and the schematic for the DEM, the Hartman appears to be essentially an adaptation of a Reticon-based flanger to a Matsushita/Panasonic platform, with the addition of a 4049-based buffer to give some addition current oomph to the clock signal so it can overcome the inherent input capacitance of the MN3007 and accept much higher clock frequencies.
> 
> The SAD1024 had a much lower input capacitance on the clock pins, so you could feed it clock pulses well in excess of 100khz without having them turned from square to trapezoidal or triangle. The MN3007 had much higher capacitance on those same pins. Normally, it would be quite comfortably driven by its companion MN3101 clock chip, but the datasheets indicate that you shouldn't aim for more than 100khz max freq. That limitation is what made the Boss BF-2, and so many similar designs, less inspiraing as flangers. They simply couldn't achieve delays much shorter than 1msec, because of the clock freq limit, because of the input capacitance, because of the absence of something to goose the current of the clock-chip output. The Reticon could handle 1mhz clocks without any outside help, which is why many of the most desirable flangers would use the Reticon chip.
> 
> However...I'm not seeing a 4046 chip on the board. Did you mean to write 4049, or are you referring to something entirely different?


Yup, I meant 4049.


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## mhammer (Nov 30, 2007)

What if you subbed a higher-wattage 100R for the stock 1/4W? You might burn out the 4049 but 4049 chips are cheap.


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## bduguay (Jul 15, 2009)

I was thinking about doing just that.
B.


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## Louis (Apr 26, 2008)

After reading this Thread ,

I find there is some pretty nice folks here !!


Great place to be !!


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## mhammer (Nov 30, 2007)

bduguay said:


> I was thinking about doing just that.
> B.


I don't know nearly enough about them, but I understand that 4049s can vary sometimes, in terms of noise and current draw; one of the things that leads people to socket them in overdrives and try different ones. So, assuming the existing 4049 isn't fried (is it socketed?) it may draw enough current to overheat a 1/4W resistor. Would a 1/2W be enough or is 1W what you need to avoid fuse-like action? I don't know. The other route would be to see if a higher value resistance would drop current sufficiently to stay alive.

Maybe it's time to contact Hartman.


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## bduguay (Jul 15, 2009)

Unfortunately, it seems he has closed shop. I measured the temperature on the resistor at highest of 60C. Any idea of what they'll take? I've never looked up that spec before...
B.


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## mhammer (Nov 30, 2007)

I think this may be the point at which the query should be directed to the stompbox forum, where the _*real*_ EEs can respond, because at this point I'm at the perimeter of my expertise.


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## sulphur (Jun 2, 2011)

I had asked because mine is a PCB unit and that component looks charred.

Probably not an isolated case.


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## mhammer (Nov 30, 2007)

Charlie "Moosapotamus" Barth has a schematic for an MN3007 version of the A/DA Flanger here: ADAflanger-MN3007 It also uses a CD4049 for a clock-line buffer/driver to overcome the input capacitance on the MN3007. But I'm not seeing any sort of current-limiting resistor between V+ and the 4049 power pin, so I don't know what's up with that. The John Hollis Ultraflange also uses a 4049 for the same purpose without any current limiting on the power line.


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## bduguay (Jul 15, 2009)

There's a 13v Zener diode at play here too. I swapped it out and now everything is running cool as a cucumber.
B.


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## CMCRAWFORD (Mar 17, 2014)

Thanks again to Brian for a job well done. Finally had a chance to plug it in and it sounds amazing. Can't recommend Brian enough, this is the second pedal he has fixed up for me.


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## bduguay (Jul 15, 2009)

It's killer for sure eh?
Thanks for the props!
B.


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## JC103 (Oct 6, 2007)

@CMCRAWFORD do you still have the Hartman? How's it working out for you?


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## CMCRAWFORD (Mar 17, 2014)

It moved on like so many of my pedals. If you have room for it is an amazing pedal.


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