has anyone successfully done LEDs for the C33?

[psychoaudio]

Some lamps are out on the C33. so im thinking of going to LED. . Has anyone successfully done this to their C33? Where did you purchase the kit?

P.S lets not make this a LED Vs Incandescent debate. Thank you

 

[jlovda]

What does successful mean? Finding a physically equivalent light with 6" pigtails or finding an LED that looks the same as incandescent? The pigtail leads seem to make any replacement bulb relatively expensive.

 

[psychoaudio]

Hi @jlovda. all of the above. a direct LED swap or similar Bipin T1 3/4 base. Im ok going with warm white or green. need a proven product/vendor to go to. Thanks

 

[jlovda]

Did you remove the front glass and look at the lamps? They are not bipin with 1/8" stiff pins. They start out with a similar bulb but they have 6" pigtail leads. That is the way Mcintosh Parts sells them and they're pretty expensive. On the last two C33's I restored I made my own by starting with 6.3v 2181 T 1-3/4 lamps with 1" leads (reminded me of old NE-2 bulbs) and soldered 24 ga black stranded wire to them along with very thin shrink tubing to cover the soldered joints. Maybe someone sells LEDs with the leads attached but I haven't seen them. Making five of these was one of the most time consuming parts of the project. The leads go back into the chassis and then make a U-turn and come back out to the front where they are soldered to posts. Three on one side and two on the other. Because the 6.3v bulbs are being run at 5vac, they last a very long time.

 

[kevzep]

LED wont work on the C33 type faceplate with the way the light is diffused, I just use the long life incandescent, they will last years and look correct.
There is no reason to re-invent the wheel......

 

[baeron]

Agreed with Kevzep. I have my C33 at a McIntosh repair shop for some restoration.
and we agreed to install new lamps as long it was being worked on.

 

[psychoaudio]

Did you remove the front glass and look at the lamps? They are not bipin with 1/8" stiff pins. They start out with a similar bulb but they have 6" pigtail leads. That is the way Mcintosh Parts sells them and they're pretty expensive. On the last two C33's I restored I made my own by starting with 6.3v 2181 T 1-3/4 lamps with 1" leads (reminded me of old NE-2 bulbs) and soldered 24 ga stranded wire to them along with very thin shrink tubing. Maybe someone sells LEDs with the leads attached but I haven't seen them. Making five of these was one of the most time consuming parts of the project. The leads go back into the chassis and then make a U-turn and come back out to the front where they are soldered to posts. Three on one side and two on the other. Because the 6.3v bulbs are being run at 5vac, they last a very long time.

Thanks @jlovda . Yes the 2181 rated @ 20K hours with 4 MSCP is the correct incandescent replacement . I believe you can get them with leads thru AK vendor @dgwojo . He has LED kits as well by the way.

View attachment 2011405 View attachment 2011406

LED wont work on the C33 type faceplate with the way the light is diffused, I just use the long life incandescent, they will last years and look correct.
There is no reason to re-invent the wheel......

@kevzep thank you for your reply. Yes LED's are directional but ive seen them used on the C28 and C27 etc.. with no problems. No hot spots and they illuminate brighter and sharper. The issue is the type of lamps used for the C33. They come with leads and needs to be soldered. The LED equivalent is not as readily available . LED's run cooler and lasts three times longer than incandescent. They are also rectified so there's no polarity and no flicker on an ac circuit. Its more about making it more efficient as opposed to reinventing the wheel. Im going to LED on the Mc2255 and want to match it all up.

 

[MACKIE1975]

LEDs are ok with MC2155. The only place that you will see blotchy is the meter illumination due to the fuse type LED shall have 3 small LEDs which will create a hot spot.

 

[MACKIE1975]

 

[MACKIE1975]

Something likes this may work but mostly available in 12V

 

[62caddy]

View attachment 2011848

Those are for MC2125 & MC2155 meters.

MC2255 meters uses four small individual lamps - not fuse style.

 

[62caddy]

Something likes this may work but mostly available in 12V

View attachment 2011862

This style used for tuner dial illumination.

 

[62caddy]

@kevzep thank you for your reply. Yes LED's are directional but ive seen them used on the C28 and C27 etc.. with no problems. No hot spots and they illuminate brighter and sharper. The issue is the type of lamps used for the C33. They come with leads and needs to be soldered. The LED equivalent is not as readily available . LED's run cooler and lasts three times longer than incandescent. They are also rectified so there's no polarity and no flicker on an ac circuit. Its more about making it more efficient as opposed to reinventing the wheel. Im going to LED on the Mc2255 and want to match it all up.

There's an LED kit on eBay for MC2255. Posting ebay links not permitted but should be easy to find.

 

[psychoaudio]

There's an LED kit on eBay for MC2255. Posting ebay links not permitted but should be easy to find.

Thank you Eric. Yes I've seen it. LED's for the C33's are also available from one particular vendor but w/o the extended hardwired leads. David Wojnarowski has the LED equivalent with extended leads..much better cost.. for future reference for C33 owners.

 

[62caddy]

I installed those fuse style LED (blue) in the MC2125s and the MC2155 but left all the original incads alone. The reason was the cracking of the meter boxes the regular incads were causing, plus I was finally able to achieve a color match between the meters of all three amplifiers which was near impossible with the incads. The only drawback is that they're quite bright.

 

[psychoaudio]

I installed those fuse style LED (blue) in the MC2125s and the MC2155 but left all the original incads alone. The reason was the cracking of the meter boxes the regular incads were causing, plus I was finally able to achieve a color match between the meters of all three amplifiers which was near impossible with the incads. The only drawback is that they're quite bright.

did you try experimenting with darker light gels to help diffuse the light a bit? or maybe using light condoms?

 

[kevzep]

@kevzep thank you for your reply. Yes LED's are directional but ive seen them used on the C28 and C27 etc.. with no problems. No hot spots and they illuminate brighter and sharper. The issue is the type of lamps used for the C33. They come with leads and needs to be soldered. The LED equivalent is not as readily available . LED's run cooler and lasts three times longer than incandescent. They are also rectified so there's no polarity and no flicker on an ac circuit. Its more about making it more efficient as opposed to reinventing the wheel. Im going to LED on the Mc2255 and want to match it all up.

Seems like a lot of work, but of you're up for it then experiment away......
You should see the lengths McIntosh went to make the LED illumination work in the newer gear, there is a lot of fibre optics and so forth.....
Good luck...

 

[62caddy]

did you try experimenting with darker light gels to help diffuse the light a bit? or maybe using light condoms?

Experimented plenty but it was hopeless. Further compounding the issue were the plexiglass (blue) filters on the faceplate all of which had various degrees of fading. The brute force of the LEDs bulldozes right past all the irregularities between the filters but bright meters is the price. But it also helps save the meter boxes so 2/3 won...

 

[psychoaudio]

Seems like a lot of work, but of you're up for it then experiment away......
You should see the lengths McIntosh went to make the LED illumination work in the newer gear, there is a lot of fibre optics and so forth.....
Good luck...

I get the hesitation. Im part of the "if it aint broke dont fix it" crowd myself. the good news is the replacement LED's come with appropriate leads so there's no extra work involved.. I can always revert back to incandescent.. I'll post the results once it's all done. Your input is much appreciated.

 

[jlovda]

Thank you Eric. Yes I've seen it. LED's for the C33's are also available from one particular vendor but w/o the extended hardwired leads. David Wojnarowski has the LED equivalent with extended leads..much better cost.. for future reference for C33 owners.

Who is David Wojnarowski? Does he have a business name or website?

Second, The lamps that I have seen use either simple series diode or a current limiting resistor (don't remember) so they are off 50% of the time and will flicker. I don't know how long LEDs would last with AC and reverse current. The only way to eliminate the flicker would be to put a tiny circuit board with a full wave bridge and filter cap before the lamps. If the original bulbs in the preamp lasted ~35 years, running 20K+ hour life 6.3 v. lamps at 5 v. will take your preamp to 2055. Has anyone seen how the LEDs in modern Mcintosh units are driven? Probably DC.