MX110, MR71, MR67: when brand new was dial illumination blue or green?
- Thread starter monkboughtlunch
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monkboughtlunch
Super Member
FYI - I tried the green LEDs with the blue gels removed. There was virtually no difference -- just slightly more pure green without the gels. I think the gels are only somewhat effective if you are using old style yellowish incandescent bulbs (no longer available from McIntosh or Audio Classics) or warm white LEDs. After experimenting I found the green LEDs with the gels removed to be the most visually appealing -- even better than gels with warm white LEDs.
Back in the 1960s, McIntosh was trying to achieve green effect, and since LEDs were not available commercially, they had to combine yellow bulbs and blue gels (yellow + blue = green).
Thanks. I think I'll go with the green for the MX110 and blue for the MX113. Incidentally Terry had once replaced the gels on my MX110. I have no idea where he got them from nor whether they remain available.
Your observations on gels having very little effect when LEDs corresponds with my own experience when I went with blue LEDs for the meters in my MC2125s and MC2155 when I was trying to color match the meters of all three amplifiers. With LEDs are installed, the color irregularities between the three amplifiers was immediately, and effectively, eliminated. Only slight drawback is the brightness.
I'll also have to check with @jlovda on which green LEDs he used for the MX113 panel lamps.
Your observations on gels having very little effect when LEDs corresponds with my own experience when I went with blue LEDs for the meters in my MC2125s and MC2155 when I was trying to color match the meters of all three amplifiers. With LEDs are installed, the color irregularities between the three amplifiers was immediately, and effectively, eliminated. Only slight drawback is the brightness.
I'll also have to check with @jlovda on which green LEDs he used for the MX113 panel lamps.
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monkboughtlunch
Super Member
When I replaced the EM87 magic eye tube in my MX110 yesterday, I noticed that McIntosh used that same blue type of gel as a filter in front of the magic eye tube. I left that gel in place. I think McIntosh wanted to mute the intensity of the magic eye tube so it was equivalent in brightness to the MPX indicator light which is lit by a bulb and filtered through a thick piece of red plastic with silkscreening. I repositioned my MPX indicator gel yesterday while I had the unit opened up. The McIntosh employee who positioned the MPX Stereo gel back in the 1960s must have been counting off the minutes to lunch because the gel was not level and the text "MPX Stereo" angled down slightly. I figured I might as well fix that while I had the unit disassembled. 
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monkboughtlunch
Super Member
RE: modern day blue gel replacement part number for authentic gel color and thickness
McIntosh used a blue-tinted theater gel in front of the magic eye tube and both sides of the dial glass.
I found that the gel on the dial glass has held up quite well and doesn't really need replacement.
However, I noticed that when the foam in front of the magic eye tube rots, the eye tube moves closer to the blue gel and makes contact. This contact heat can burn a thin horizontal line in the gel. If you go to the trouble of installing a new magic eye tube and foam, you might as well put in a fresh strip of theater gel in front of the tube. New theater gel can be purchased for only a few bucks.
Here's where something that should be simple and straightforward gets muddled. Did McIntosh ever publish the gel part number they used?
I haven't seen a definitive thread with the confirmed brand and model number of blue gel that McIntosh used. Part numbers and gel colors are all over the map.
For example, I've seen different posts say use "Lee Steel Blue #117" or "Rosco Nile Blue #70" or " Times Square Lighting Parts Express #244-141 (118 bright blue)."
I decided to see how the Lee #117 compares with the original gel McIntosh used in the dial glass location. See image below.
In comparing the two side by side, the original 1960s McIntosh gel was significantly thicker and seemed more robust than LEE 117 -- as if the old MAC gel was designed for high temperature applications.
The LEE 117, in contrast, was quite thin and seemed less suitable to being in front of a hot tube or bulb for a long period of time.
The colors were close but not precise. The original gel McIntosh used has a slight bit more green and the added thickness makes it a bit more opaque.
I think there is probably another gel model # that represents what McIntosh originally specified.
The LEE #117 doesn't come in a high temperature version. But LEE makes another gel called #172 Lagoon Blue that has more green and is offered in a high temperature variant and might be a more robust and authentic option than the #117.
I found an old post talking about Rosco # R70 Nile Blue. Not sure if the Rosco is thicker like the original MAC gel. The LEE equivalent to a Rosco R70 is apparently the LEE #140 "Summer Blue." The Rosco promo verbiage says "Rosco's premier range of filters are manufactured in a unique technology to insure the longest possible life under hot theatrical lights. Three discrete layers are combined in a tri-extrusion process. By sealing the colored layer between two microscopically thin layers of clear film, dye migration is minimized and effective life is extended." So perhaps the Rosco is thicker and more robust than the LEE 117?
The Times Square Lighting 118 sold by Parts Express appears to use the same color numbering scheme as LEE. So in theory it should be the same color as LEE #118.
So in conclusion, if we take all three gels folks are using and equate them to LEE equivalents, below is a swatch image for comparison from the LEE web site.
LEE part numbers below:
118 - Light Blue: Times Square (Parts Express). Lee offers equivalent in a high temperature.
117 - Steel Blue: Lee
140 - Summer Blue: Rosco R70
172 - Lagoon Blue -- Haven't seen this one used, but has a bit more green than 117 and is offered in high temperature.
Wild Card:
Rosco 363 -- perhaps a thicker more correct equivalent to LEE 117
So at this point, LEE #117 appears to be incorrect as a robust, color accurate replacement (unless a thicker ROSCO 363 equivalent was used), leaving 118, 140 and 172 as potential LEE equivalent gel options of what MAC originally used.
Anyway, this quest led me down a rabbit hole and I've probably spent way too much time tonight trying to figure out the authentic part number. But it would be cool to nail it down for posterity.
Anyone know what the actual brand and part number is that MAC used?
McIntosh used a blue-tinted theater gel in front of the magic eye tube and both sides of the dial glass.
I found that the gel on the dial glass has held up quite well and doesn't really need replacement.
However, I noticed that when the foam in front of the magic eye tube rots, the eye tube moves closer to the blue gel and makes contact. This contact heat can burn a thin horizontal line in the gel. If you go to the trouble of installing a new magic eye tube and foam, you might as well put in a fresh strip of theater gel in front of the tube. New theater gel can be purchased for only a few bucks.
Here's where something that should be simple and straightforward gets muddled. Did McIntosh ever publish the gel part number they used?
I haven't seen a definitive thread with the confirmed brand and model number of blue gel that McIntosh used. Part numbers and gel colors are all over the map.
For example, I've seen different posts say use "Lee Steel Blue #117" or "Rosco Nile Blue #70" or " Times Square Lighting Parts Express #244-141 (118 bright blue)."
I decided to see how the Lee #117 compares with the original gel McIntosh used in the dial glass location. See image below.
In comparing the two side by side, the original 1960s McIntosh gel was significantly thicker and seemed more robust than LEE 117 -- as if the old MAC gel was designed for high temperature applications.
The LEE 117, in contrast, was quite thin and seemed less suitable to being in front of a hot tube or bulb for a long period of time.
The colors were close but not precise. The original gel McIntosh used has a slight bit more green and the added thickness makes it a bit more opaque.
I think there is probably another gel model # that represents what McIntosh originally specified.
The LEE #117 doesn't come in a high temperature version. But LEE makes another gel called #172 Lagoon Blue that has more green and is offered in a high temperature variant and might be a more robust and authentic option than the #117.
I found an old post talking about Rosco # R70 Nile Blue. Not sure if the Rosco is thicker like the original MAC gel. The LEE equivalent to a Rosco R70 is apparently the LEE #140 "Summer Blue." The Rosco promo verbiage says "Rosco's premier range of filters are manufactured in a unique technology to insure the longest possible life under hot theatrical lights. Three discrete layers are combined in a tri-extrusion process. By sealing the colored layer between two microscopically thin layers of clear film, dye migration is minimized and effective life is extended." So perhaps the Rosco is thicker and more robust than the LEE 117?
The Times Square Lighting 118 sold by Parts Express appears to use the same color numbering scheme as LEE. So in theory it should be the same color as LEE #118.
So in conclusion, if we take all three gels folks are using and equate them to LEE equivalents, below is a swatch image for comparison from the LEE web site.
LEE part numbers below:
118 - Light Blue: Times Square (Parts Express). Lee offers equivalent in a high temperature.
117 - Steel Blue: Lee
140 - Summer Blue: Rosco R70
172 - Lagoon Blue -- Haven't seen this one used, but has a bit more green than 117 and is offered in high temperature.
Wild Card:
Rosco 363 -- perhaps a thicker more correct equivalent to LEE 117
So at this point, LEE #117 appears to be incorrect as a robust, color accurate replacement (unless a thicker ROSCO 363 equivalent was used), leaving 118, 140 and 172 as potential LEE equivalent gel options of what MAC originally used.
Anyway, this quest led me down a rabbit hole and I've probably spent way too much time tonight trying to figure out the authentic part number.
But it would be cool to nail it down for posterity.Anyone know what the actual brand and part number is that MAC used?
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monkboughtlunch
Super Member
Does anyone know the max temperature that an EM87 magic eye tube achieves when operating properly? Am trying to determine the proper gel temperature rating.
monkboughtlunch
Super Member
Here you go: https://www.ebay.com/itm/CUSTOM-FUSE-LAMP-FOR-MARANTZ-MCINTOSH-SANSUI-OTHERS/372256608830
Select 42mm 6.3VAC and green
Wow... I can't begin to tell you how helpful this thread has been.
I'm in the midst of refreshing a McIntosh MR71 (tuner) and C22 (preamp).
From the service manuals I found online my C22 takes the same festoon lamps (058-033) as your MX110, so I feel pretty confident ordering per the specs you detailed earlier (42mm; green; 6.3VAC).
For any new readers, the seller's link has moved to https://www.ebay.com.sg/itm/CUSTOM-...hash=item41fd71351a:m:mPh5PK6Ik1C1Y9La1wwUvcQ
I just wanted to see if you might have the answer to two questions/concerns...
1. other vendors are advertising they use a white teflon tape to deflect the light to one side of the bulb (and mirror a strip of white paint that was used on the original). Did the lamps you bought from qua-co have the white strip?
2. My MR71 tuner is missing the original lamps (p/n 058-032), so I can't measure them to get a cross from qua-co; I've written qua-co for advice, but wanted to see if you might have any suggestions on how to cross (I think it's wider at 7mm vs 6mm, but not 100% sure).
Thanks for any advice or feedback you might be able to offer and for the detailed photos and info listed above.
I just dealt with this issue on my MR67 tuner. The 42 MM lamps work for a MR67, I am sure the MR71 will take the same. I ordered from qua-co and they do not have the tape. The lighting element only focuses the light in one direction.
On a related note, I needed a funny size on a Fisher FM-50B tuner, which ended up being a 35 MM warm white. I contacted qua-co and he can make custom sizes. So if you find out that you need a custom size, qua-co is the one. Just contact him through eBay messages and explain what you need.
BTW if you do not want the LED, a replacement for the original bulbs is available at RR. http://www.rr-artifacts.com/mcreplacementfestoons.htm
Audio Classics has the correct color gels.
On a related note, I needed a funny size on a Fisher FM-50B tuner, which ended up being a 35 MM warm white. I contacted qua-co and he can make custom sizes. So if you find out that you need a custom size, qua-co is the one. Just contact him through eBay messages and explain what you need.
BTW if you do not want the LED, a replacement for the original bulbs is available at RR. http://www.rr-artifacts.com/mcreplacementfestoons.htm
Audio Classics has the correct color gels.
Thanks, Patrick... very helpful.
Messaged qua-co via ebay a couple of days ago, and now playing the waiting game.
I think you're right about the 42 mm length... my remaining concern is now regarding the voltage.
RR is quick to point out the two bulbs they offer for my two different units aren't interchangeable.
If I stuck with the original bulbs, RR says to use a 7V 285mA for my C22 preamp (the same bulb you'd use on your MR67) and a 6.3V 250mA for my MR71 tuner.
Do these differences go out the window when switching to LED?
I realize I may be overthinking this, but just trying to get it right the first time.
Thanks again.
Messaged qua-co via ebay a couple of days ago, and now playing the waiting game.
I think you're right about the 42 mm length... my remaining concern is now regarding the voltage.
RR is quick to point out the two bulbs they offer for my two different units aren't interchangeable.
If I stuck with the original bulbs, RR says to use a 7V 285mA for my C22 preamp (the same bulb you'd use on your MR67) and a 6.3V 250mA for my MR71 tuner.
Do these differences go out the window when switching to LED?
I realize I may be overthinking this, but just trying to get it right the first time.
Thanks again.
clinic-audio
all on YAMAHA untill 1990
Hello
To make it right the first time is using original lamp not LED
To make it right the first time is using original lamp not LED
mozcho
Well-Known Member
Very interesting and informative thread. There seems to be different colors used in different periods: green, teal, and blue. Can somebody in the know tell us what years and models serve as the watersheds between these colors? And if we go the LED way, should we use pure white or warm white or yellow?
Also I think this should be pinned.
Also I think this should be pinned.
I installed the green LED in the MX110 suggested by @monkboughtlunch and couldn't be more pleased with the results. They give a real "period" look as many units had green illumination at the time. Dial illumination of the MAC1500 was also originally green. I had also tried the blue LED but didn't care for it which was more of a violet than blue. The LEDs also make the dial markings of the MX110 much clearer and sharper than with the ordinary incads.
I retained the replacement blue gels that Terry had installed which will not melt/deform with the LEDs as they would with the standard lamps. The only drawback is that the dimming switch has little effect on the LEDs.
Like updated knobs, it's easily reversible for those who insist on authenticity. But the effect (to my eyes) is so much better, I don't know why anyone wouldn't want to.
I retained the replacement blue gels that Terry had installed which will not melt/deform with the LEDs as they would with the standard lamps. The only drawback is that the dimming switch has little effect on the LEDs.
Like updated knobs, it's easily reversible for those who insist on authenticity. But the effect (to my eyes) is so much better, I don't know why anyone wouldn't want to.
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Do you happen to have a link? I need to replace lamps in my 110. TIA!
Thanks!
Any suggestions for the MPX stereo lamp? That does not seem to be working either.
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