Musitronics - Mutron Phasor II

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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Fuzzer
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Post by Fuzzer »

audiohub wrote:That's it exactly. The noise level doesn't change, but if the signal level is larger going in, then that fixed amount of noise the phaser chain generates becomes a less significant part of the whole signal.
All right, that's where I was heading with it, thanks for expanding the explanation :thumbsup
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reb
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Post by reb »

Well I'm going to replace the diodes in mine and report back. It shouldn't be this noisy. I have a Mutron II which is pretty quiet.

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chicago_mike
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Post by chicago_mike »

How does this ohaser sound compared to others...

notably the maestro.

Inquiring minds want to know. :)
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damnyankee
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Post by damnyankee »

audiohub wrote:These pedals often get a bad rap for being noisy, when in fact they are often just driven with too low of a signal.
If you use this as a stompbox with a guitar level signal, and then into a higher gain setup, you'll be amplifying the phaser chain
noise along with your guitar signal. These units are really made to accept a line level signal, and will work much better in an
effects loop or preamp/poweramp insert type of situation if that's possible with your setup. They can accept several volts of input
signal without distortion, and the noise level will drop accordingly.
Mine isn't too noisy, but I place mine in the effects loop AFTER EQ/distortion or overdrive, compression, EQ #2. Sometimes I'll put it infront of my chorus, sometimes not. But DEFINITELY BEFORE my echoplex or lexicon reverb (whichever delay I'm in the mood for which is last in the chain).

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Post by zzzapfizz »

How are the LDR arrangement done in this pedal? Is it that black cylinder looking like a cap?
Are there any reference to L/D resistance on the schematics?

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foxfire
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Post by foxfire »

i just got myself a Mutron Phasor II and i am so underwhelmed that i'm starting to think that maybe Santa Claus isn't really real...there is so little effect. it's almost as though the low half of the sweep is not there at all. my morley pfv is way stronger than this mutron. i only just got it last night so i haven't had too much time to look inside yet. i was wondering if anybody any voltages o this thing over the years?

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Post by grantb »

I've got one I need to repair. The sweep is intermittent. When it does sweep, it makes giant spacey swooshes. This one needs a recap for sure... hopefully that's all.

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Post by n8b5150 »

grantb wrote:I've got one I need to repair. The sweep is intermittent. When it does sweep, it makes giant spacey swooshes. This one needs a recap for sure... hopefully that's all.
I've repaired two of these that had LFO IC's with cold solder joints. In both cases, I had to remove the IC, clean the legs and solder pads and resolder the ic's.

In my Phasor II, the IC's are TL082's and the resistor listed as 330 coming off of the 1k trim pot is 220. Other than that, everything else is the same. Mine is working great and is not noisy at all. I haven't had the courage yet to desolder the ldr can to reverse engineer it.

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grantb
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Post by grantb »

n8b5150 wrote:
grantb wrote:I've got one I need to repair. The sweep is intermittent. When it does sweep, it makes giant spacey swooshes. This one needs a recap for sure... hopefully that's all.
I've repaired two of these that had LFO IC's with cold solder joints. In both cases, I had to remove the IC, clean the legs and solder pads and resolder the ic's.
...
Ah, thank you very much! Your post made me go back and check for bad joints again. Mine was on the same chip. This board had a lot of polluted looking joints before I fixed them, but I missed that one. Maybe the shield plate exerting mechanical stress on the pins of that chip is what makes it fail first. It's a very well designed unit IMO, too bad about the soldering.

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delayed
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Post by delayed »

Does anyone know what can replace the transistors in the phasor II?
2sc1852 = ?
2sc828 = ?
2sa666 = ?

I am looking to replace them but Mouser does not show stock on these.

Thanks,

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Post by mictester »

delayed wrote:Does anyone know what can replace the transistors in the phasor II?
2sc1852 = ?
2sc828 = ?
2sa666 = ?
2SC1852 --> BC337

2SC828 --> BC183L

2SA666 --> BC327

These are not 100% equivalents, but they'll work perfectly.
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Post by delayed »

Thank you for the information!

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Post by arayita »

delayed wrote:Does anyone know what can replace the transistors in the phasor II?
2sc1852 = ?
2sc828 = ?
2sa666 = ?

I am looking to replace them but Mouser does not show stock on these.

Thanks,
2SC1852=2N4401

I'm 100% sure because I've seen original schems from Musitronics

Greetings

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borislavgajic
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Post by borislavgajic »

this is led/ldr arangement of BiPhaser......but it is similar to Phaser II.........

cheers

Boris
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arayita
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Post by arayita »

Hi there

I've finished my Phasor II clone-prototype successfully
After a few of corrections to my layout (and an error with the schem posted here some time ago) I'm playing that amazing phaser...

My english is so bad to explain how good it sounds, I'm so f*ucking happy with my clone. It were a lot of months studing and reading about Mutron technology (and almost everthing was in english :? )

At this moment it's w/out a box (just PCB and external controls for testing). I'll post my finished work later...

Well, I leave a pair of guts (sorry, they're from my cell phone) and a lo-quality sample (from my cell phone too)

Cheers from Chile

Diego
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Post by sinner »

Thank you, but the archives are corrupted :(

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borislavgajic
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Post by borislavgajic »

Great ....thanks ..... :thumbsup


can you tell us more about error on schem?
what do you mean?

cheers

Boris

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Post by arayita »

Hi

hummm, I'll post guts and sound samples when I finish my work... I'm not shure about post my complete work (PCB/Layout) I'm not interested in people selling clones w/ MY work :? What about that in this forum? At least in my country some people used to do this... :( Probably I'll post my schematic with corrections...

About error on schematic...

I don't remember very weell because I haven't my docs with me right now... but it was on LFO circuit... An IC between Rate and Depth controls was wrong connected, and wrong noted (pin 5 as - input)... But fortunatelly it's easilly to fix

Cheers

sinner: what do you mean with "corrupted"?? Don't you can download anything?

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Post by skumberg »

From the trace pictures it looks like the schematic error is just like arayita said. Looking at the schematic the 0,47uf connecting to pin 7 and 5 on IC6B, should be connected between pin 7 and 6. Pin 5 goes to ground just like pin 2 on IC6A.

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Post by arayita »

Right skumberg! :wink: This was the problem. When I connected the IC with wrong schem it sounded with an old radio noise :shock: I was very disappointed :(

I'll upload corrected schematics today

cheers

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