Distinction bet. MC2505 and MC2505-2 ?

Also, if I understand correctly, if one has a Series 1 unit and installs a Series 2 replacement glass (due to bubbling or cracked glass), the "Meter Range" potentiometer's four positions will point to the incorrect settings because Series 2 changed the locations of each potentiometer position. Is that correct?

Yes , it is a switch but this is correct ! this is not a problem to use the unit this way
 
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VintageMac said:
And you are bashing McIntosh about this without even knowing if the glass is the same or not between the two versions?

Larry
Click to expand...

Feedback from McIntosh:

"We only have one style of glass. It is part #01607800, it is in stock and is $117.80 plus shipping."

A search for the #01607800 part number returns these images. The MAC replacement glass is clearly designed for the series 2 meter range pot and non-bezeled meters.

s-l1600-3.jpg

s-l1600-7.jpg

 
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Feedback from McIntosh:

"We only have one style of glass. It is part #01607800, it is in stock and is $117.80 plus shipping."

A search for the #01607800 part number returns these images. The MAC replacement glass is clearly designed for the series 2 meter range pot and non-bezeled meters.

That's what I said last saturday
 
Sometimes it's difficult to get a precise answer from McIntosh for specific questions concerning older equipment.

The main issue is the meter switch nomenclature, otherwise the replacement glass looks fine on units with the bezel meters. Nobody would ever suspect it wasn't OEM factory spec glass.

Can anyone answer these questions:

1: Do all MC2505 w/bezel meters have earlier meter range switch?

2: Can anyone confirm the existence of a McIntosh Service Bulletin for early MC2505 for replacement of the meter range switch with the later style?
 
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1: Do all MC2505 w/bezel meters have earlier meter range switch ? I had plenty for repair but did not record it in my notes .

2: Can anyone confirm the existence of a McIntosh Service Bulletin for early MC2505 for replacement of the meter range switch with the later style ? No I can't but you can take a look on all service manuals and all owner's manuals !

Just for the information I know 14 differents service manuals for MC2505 ......and 2 for owner's manuals
 
I found it on RR's website.

mcgrimm.jpg


"Here is Jim Grimm, a McIntosh engineer in 1969, working on a revised MAC1700 receiver. Jim adapted a triac circuit to protect the loudspeaker from DC current in case of output transistor failure. He was the only person to notice that the meter switch on the MC2505 went from the off position to the most sensitive position before going to the less sensitive positions. The switch was changed to the least sensitive position after the off position."

The above suggests the earlier switch was limited to a few very early production units, but Roger does not state for certain when the change was made.
 
62caddy said:
The above suggests the earlier switch was limited to a few very early production units, but Roger does not state for certain when the change was made.
Click to expand...

The Berners web site notes there were 11,421 total units manufactured during the nearly 11 year production run. Sometime prior to 43Kxx serial, the change from Series 1 to Series 2 occured. Serial numbering started at 10K01. Therefore, as many as 3,299 units may have been produced with the recessed meter bezel and original METER RANGE configuration (4300 - 1001 = 3299). Thus as many as roughly 29% of all MC 2505 units manufactured were Series 1 units (3,299 / 11,421 = 28.8%).

Source: I found the below quote on Berners site. http://mcc.berners.ch/power-amplifiers/MC2505.pdf

"MC 2505 meters featured bezels that were recessed behind the glass and hand a METER RANGE switch from OFF to O.

Somewhere between the 32Kxx serial number and the 43Kxx serial number, the model designation was changed to the MC 2505-2 and featured meters without the bezels and mounted against the glass. The METER RANGE switch for the MC 2505-2 was opposite of the MC 2505 and ranged from -20 to OFF.

The model designation (MC 2505) on the faceplate was not changed.

MC 2505 and MC 2505-2 - Sold from January 1967 - December 1977. S/N 10K01 - 99K99 and AT1001-AT3424 (11,421 units)"
 
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Here's an example of photos I found online of another "Series 1" MC 2505 for documentation. Personally, I think the original 1960s design with the recessed beveled meters are cool looking.

Note the bubbling around the headphone jack. Common problem. Sadly, if the glass is replaced, the angled beveling effect around the meters will be partially occluded and the METER RANGE pot positions will labeled incorrectly.

I looked at the service bulletins on Hi Fi engine and didn't see one for the METER RANGE change.

s-l1600-11.jpg

s-l1600-12.jpg

s-l1600-10.jpg
 
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Sounds like monk wants to invest in a silkscreen operation. The process was developedby a U of Michigan intern at Mac in the early 60s.

I believe it involved fish oil based paints to get the green/gold scrip change.

I don't know if monk even owns a MC2505, he seems to be very interested in stirring up controversy, but if he does own one the diminishing supply of TO-66 semiconductors should be his top priority. Unless he wants a poor boat anchor.
 
c_dk said:
Sounds like monk wants to invest in a silkscreen operation. The process was developedby a U of Michigan intern at Mac in the early 60s.

I believe it involved fish oil based paints to get the green/gold scrip change.

I don't know if monk even owns a MC2505, he seems to be very interested in stirring up controversy, but if he does own one the diminishing supply of TO-66 semiconductors should be his top priority. Unless he wants a poor boat anchor.
Click to expand...

Sounds like you want to be inflammatory and make personal attacks.

As stated previously, I like the original 1967 McIntosh design with the exposed bezeled meter and have considered buying this well regarded amp to complement my 1967 MX110. This would be period correct.

However, given that nearly all McIntosh glass MC2505 faceplates of that era develop bubbling and/or cracks, one would need to use the McIntosh glass replacement suited for Series 2 -- not Series 1. This covers up the bezel and mislabels the METER RANGE pot.

Not the end of the world, but this thread is about the differences between the two MC2505 models and that's what's being explored.
 
I haven't explored how the Meter Range switch is designed, but is it possible to re-wire it to match the -2 faceplate (which is a better switch setup anyway)?
 
62caddy said:
How much prior is the question. Emailed Roger - unfortunately he does not have the answer either.
Click to expand...

Berners site notes "between the 32Kxx serial number and the 43Kxx serial number."

This suggests as few as 2,200 and as many as 3,299 Series 1 units were produced (since the serial numbering began at 10K01). So it appears somewhere between 19% - 29% of all units were Series 1 if Berners data is accurate.
 
wow..great info everyone! serial number of the piece im looking at is 71K31. So I suppose It has the earlier faceplate
 
Here are some pics
 

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