Use of Phase 90

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Re: Use of Phase 90

Postby garbeaj » Wed May 25, 2011 10:37 am

Ted B wrote:
garbeaj wrote:
Good Guest wrote:Ed did say that his flanger was modded for keeping gain levels the same...

I know he said his MXR pedals were modded by Jose Arredondo for "treble boost", but most agree that is bullshit. ...


The Phase 90 references in question appear Jas Obrecht's 1978 interviews, where Ed makes the following comments:

"It (Phase 90) doesn't really phase; it just kind of gives you treble boost, which I like. Cuts through for solos."

"And I use an MXR Phase 90 phase shifter that gives me treble boost for solos, too."

Realize that what you're reading is a 21-22 year-old Ed explaining something a bit technical to a journalist in his own terms, and that being filtered and repeated in a manner that makes sense to Obrecht. In other words, Ed appears to be describing the purpose of the Phase 90 being to make his solos stand out a bit, not for the phasing effect itself (which is why the knob is set on full slow). Of course, we're talking about this years later, so evidently it worked.


The only reference I recall where he specifically points to Arredondo modding any effects concerns the Univox having a "different motor" that allows it to go slower. Whether that means different motor, or, a mod that makes it behave as if it had a different motor, the end result is the same. Ed's appears to be explaining a technical mod that isn't his own to a journalist in a manner that makes sense in layman's terms.


In the first Jas Obrecht interview I see where he gives the same old story about the "different motor" in the EC-80A, but he does not mention that the person that did the work was Arredondo. Is there some other interview where he specifically mentions that Arredondo was the guy that did this work?
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Re: Use of Phase 90

Postby Ted B » Wed May 25, 2011 10:49 am

No, the only references I find that mention Arredondo specifically pertain to the amp, not the effects. It seems this is another instance whereby we've made an assumption that wasn't necessarily true, even if it's mostly academic.

leadguy wrote:I've been looking at some schematics and the mid 1970s Phase 90s schematics are very different from the recent Phase 90 and Phase 90 script reissue schematics.


That's interesting (I haven't compared the schematics). Nevertheless, Dunlop appears to have done convincingly well in making the '74 reissue sound like the original. What would be interesting is to determine if they sound just as similar with other effects (e.g. EP3) downstream.
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Re: Use of Phase 90

Postby garbeaj » Wed May 25, 2011 10:52 am

Ted B wrote:The only reference I recall where he specifically points to Arredondo modding any effects concerns the Univox having a "different motor" that allows it to go slower.


Ted B wrote:No, the only references I find that mention Arredondo specifically pertain to the amp, not the effects. It seems this is another instance whereby we've assumed something that wasn't necessarily true, even if it's mostly academic.

For the record, I never assumed that Jose Arredondo did anything to any of Eddie's effects...

Are you saying that you have never seen the interview you say you saw in the first quote? :what:

Here is what Eddie says to Jas Obrecht (from the 1980 article reprinted in the book Masters of Heavy Metal, p.156)

EVH:I have some other tricky stuff in my amps which I don't even want to talk about because if someone reads it in the magazine they are going to hit up Jose, an old guy from Argentina who knows alot of tricks and does stuff for me. He doesn't want people to know who he is because he's getting mobbed. He also puts little things inside my MXR stuff, like permanent gain controls that boost when I kick them on. I don't even know what they're called. They reduce noise and boost the signals.
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Re: Use of Phase 90

Postby Ted B » Wed May 25, 2011 10:59 am

I'm speaking rhetorically, not about you specifically. I know I had to go back and check to be sure there wasn't any such reference. I could have just as easily filed it away in my mind as fact, as I'm sure many would.

It's interesting how when even one minor detail is misstated or misinterpreted but otherwise widely accepted, it has the ability to spawn myth upon myth.
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Re: Use of Phase 90

Postby leadguy » Wed May 25, 2011 11:10 am

New

Image

New Script

Image


Changing New to New Script

Image
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Re: Use of Phase 90

Postby garbeaj » Wed May 25, 2011 11:11 am

Ted B wrote:I'm speaking rhetorically, not about you specifically. I know I had to go back and check to be sure there wasn't any such reference. I could have just as easily filed it away in my mind as fact, as I'm sure many would.

It's interesting how when even one minor detail is misstated or misinterpreted but otherwise widely accepted, it has the ability to spawn myth upon myth.

That is true...I hadn't remembered the part I just quoted until you brought up the "gain controls"...

I wonder exactly when it was that Ed met Jose. He may not have made these mods at all, or he may have modded the MXR effects at some point after the first album and tour?
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Re: Use of Phase 90

Postby leadguy » Thu May 26, 2011 3:50 am

On my standard MXR Phase 90 I removed R28 and C11 and C12 which makes it more like the script version and I adjusted the trimpot a fraction in a clockwise direction to be midway between 8 o'clock and 9 o'clock and it's now a lighter Phase effect.
Usually the trimpot is set around 8 o'clock.

The Phase effect reduces as the trimpot is turned clockwise.

http://www.erikhansen.net/mxrphase90mods.php
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Re: Use of Phase 90

Postby Ted B » Thu May 26, 2011 9:39 am

garbeaj wrote:I wonder exactly when it was that Ed met Jose. He may not have made these mods at all, or he may have modded the MXR effects at some point after the first album and tour?


Ed mentions Jose specifically in his very first interview (summer 1978), so that suggests that his relationship with Jose likely goes back further than the recording of first album. I suspect the OT replacement and bias/variac trickery to be the work of Jose.
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Re: Use of Phase 90

Postby Good Guest » Thu May 26, 2011 1:24 pm

@leadguy..

The phaser you have marked as the original is a phase101...not the original....the 101 uses a cmos switch chip instead of the the fet gates and has extra phasing stages....I'll see if Ican locate the original and post it later. :rock:
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Re: Use of Phase 90

Postby leadguy » Thu May 26, 2011 1:29 pm

Thanks for pointing that out.

I just googled around quickly and came across a forum with it on and I thought it was the Phase 90 but it ain't.

I'd be interested in seeing the original Phase 90 schematic and how it matches up to the new script.
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Re: Use of Phase 90

Postby Good Guest » Thu May 26, 2011 5:07 pm

Well here is the original complete with 741 ic chips that were pointed out earlier as being very important to the tone of the unit...

IMO the ic's are extremely inportant because they will adgust the balance between wet and dry in ways mix controls can't..which is what most modders will add to compensate for the , way off the mark gain levels, unbalanced thud tones and weak dry signals that other chips have mucked up...
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Re: Use of Phase 90

Postby T.J.Fuller » Thu May 26, 2011 5:24 pm

Good Guest wrote:Well here is the original complete with 741 ic chips that were pointed out earlier as being very important to the tone of the unit...

IMO the ic's are extremely inportant because they will adgust the balance between wet and dry in ways mix controls can't..which is what most modders will add to compensate for the , way off the mark gain levels, unbalanced thud tones and weak dry signals that other chips have mucked up...


Good Guest, let's say you put your best Jose thinking cap on and give us an opinion on this circuit based on this question....

If Ed came up to you and said... Get me a little more boost and a little more treble out of my phase 90 pedal

Where would you start looking to mod ? probably not the top half of the schematic....

What other parts could be clipped, changed or altered in this circuit to get this end result ?

the 150k resistor at point of out put?? ...the 10uf cap ??

please educate us ... because you know you have some ideas on this :thumbsup:
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Re: Use of Phase 90

Postby Good Guest » Thu May 26, 2011 9:11 pm

T.J.Fuller wrote:
Good Guest wrote:Well here is the original complete with 741 ic chips that were pointed out earlier as being very important to the tone of the unit...

IMO the ic's are extremely inportant because they will adgust the balance between wet and dry in ways mix controls can't..which is what most modders will add to compensate for the , way off the mark gain levels, unbalanced thud tones and weak dry signals that other chips have mucked up...


Good Guest, let's say you put your best Jose thinking cap on and give us an opinion on this circuit based on this question....

If Ed came up to you and said... Get me a little more boost and a little more treble out of my phase 90 pedal

Where would you start looking to mod ? probably not the top half of the schematic....

What other parts could be clipped, changed or altered in this circuit to get this end result ?

the 150k resistor at point of out put?? ...the 10uf cap ??

please educate us ... because you know you have some ideas on this :thumbsup:



For a little more treble I would reduce the input and output pre emphasis cap too...0047uf and.02uf respectivly...or I would change the .05uf caps in the top half of the circuit to .022uf.....I would do one change at a time and ask Eddy each time..Enough highs or more? Then concentrate on the tweaking the spot of interest.

For gain I would play with the output gain by changing the resistor bewteen the base and collector from 150k too 220k..470k would turn it into a fuzz....220k wouldn't upset the mixing too much but provide a beefier output

The input buffer that has the feedback shorted between 2 and 6 could be replaced with a resistor ...as it is, the gain of this buffer is 1,which is the same with the text book description of a buffer (never greater than 1).......Too increase the input gain a resistor between 50k and 220k placed between 2 and 6 would be nice ...1meg would turn it into a super gain amp approaching d+'s and such....Place a pot from 10k to 500k and have him adgust it till he likes the gain..then hardwire the value in there.

Of course one could play around with the mixing resitors and decrease wet and dry signals to allow a simulated increase in the wet and dry also...ie: you reduce the wet and let more dry thru or the opposite.

So there you have it ...many ideas to tune a phase90 to perfection...the stock circuit I posted is a fantastic starting point...

Saying all this yer probably wondering if I did any of these things ? Idid them all and I ended up just increasing the value of the mixing resistor responsible for the wet phase signal and returning everything to stock values...this allowed for more dry and a less pronounced phase signal that let pinch harmonics thru the entire range just like Ed's phase 90...I hate it when I pinch a harmonic and it disappers in the swoosh and I'm sure Eddy hated it too...I fixed that problem and have been a happy phazer ever since :) .... with 6 bands and ep3's things can get a little to out of whack adding more treble or gain... :thumbsup:
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Re: Use of Phase 90

Postby leadguy » Fri May 27, 2011 1:08 am

Thanks for the original.

The original looks pretty close to the new script, not exactly but pretty close.
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Re: Use of Phase 90

Postby leadguy » Fri May 27, 2011 1:33 am

Always try the obvious first, using the correct gear.

One of the things that might vary a bit between Ed's original and a new Script is the 250k trimpot setting depending on how the factory set the value of the trimpot and if Ed altered his trimpot.

I used the ATBL guitar hero iso and kept playing the part where Ed steps on the Phase on the G chord just before the solo starts and using this part to dial in my Phase settings as close to Ed's as I could by altering the internal trimpot a bit with the outside black knob set to Ed's settings.

Image

Dialing in the Phase trimpot settings could be done even more accurately if a Echoplex with Ed's settings is connected after the Phase because that's what we hear, the Phase going through the Echoplex.

Image

I think I got pretty close to Ed's Phase settings but I think I would have gotten closer if I was altering the trimpot on a New Script version instead of on the standard version.

The ATBL guitar hero iso with Ed stepping on the Phase on the G chord just before the solo is a good indicator of how Ed's Phase actually sounded because the G chord is sustained with the Phase effect.

When Ed steps on the Phase for the G chord, the Phase effect is not that weak but also not that strong.
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