MC 2255 Positive & Negative Driver substitutes

[Matt's Dad]

Good evening!!!

I'm looking for substitutes for the Positive & Negative driver transistors fort the MC2255. The McIntosh part numbers are as follows:

Q516 132203 MJ4247

Q521 132204 mj4237

Any help would be appreciated.

Jim

 

[c_dk]

This was beat to death a few years ago in reference to Mc2205 drivers.

Way too many opinions from posters with no skin in the game, I have tried a few options in my test case MC2250.

I have found output issues between outputs sourced from RCA, Motorola, and Harris as the semiconductor manufacturing operations were purchased and consolidated and then ultimately turned into Onsemi.

If you have managed to toast them buy them from the factory, see what engineering has cleared for use.

Anything from the web is probably counterfeit.

 

[Matt's Dad]

Both of my MC2255s are running well. One was checked out by Terry D. and the other by Ryan at Audio Classics.

I am attempting to have a stock of parts for these units for future repair. I was trying to get the advice of the techs here who repair these units as to what drivers I can get from Mouser or Digi-Key.

I know I can call McIntosh and talk to Gail regarding parts, I've done that many times so far. It's just that I'd like to be able to get the items at reasonable costs. The LDRs I ordered from McIntosh were $20. apiece... }-:

 

[kevzep]

Good to see some of the regulars making the new members feel welcome and like this is a relaxed place to hang out and talk McIntosh and maybe get some information regarding technical problems.

Welcome to the forum Matt's Dad as I see you are a new member, not everyone here bites, we area nice bunch, I promise...

 

[Matt's Dad]

So, gentlemen...

Any advice other than call McIntosh Parts and talk to Gail? I thought that this was a place where we could have our questions answered intelligently about McIntosh service and parts.

Or was I mistaken?

 

[clinic-audio]

Hello Matt's Dad

I thought that this was a place where we could have our questions answered intelligently about McIntosh service and parts.

MC INTOSH LABS is the only place where to find the drivers you are talking about . You have to know also that this problem does exist for older models with drivers 132151 and 132152 as Chris said at the beginning of answers .

Do you know how much it cost to keep during years (+30) components like those ? If the price is 8 or 10 $ each , what is the problem ? You are a Mc Intosh owner's and you have to be ready to pay the right price to get original components from official Mc Intosh retailer or from the factory . They are safe sources .

Trying to find less "expensive" components is a risk that I will not take as a pro and I am sure to buy non conterfeit semi conductors

You said :

Q516 = 132203 = MJ4247
Q521 = 132204 = MJ4237

This is not exact

Q516 = 132203 = MJ4248 = no more available replaced by 132229 = MJ15018
Q521 = 132204 = MJ4238 = no more available replaced by 132230 = MJ15019

you like precise answer , you have mine

 

[MACKIE1975]

If you can't afford a $250 oil change of the Benz or BMW then don't own one.

 

[kevzep]

Hello Matt's Dad

I thought that this was a place where we could have our questions answered intelligently about McIntosh service and parts.

MC INTOSH LABS is the only place where to find the drivers you are talking about . You have to know also that this problem does exist for older models with drivers 132151 and 132152 as Chris said at the beginning of answers .

Do you know how much it cost to keep during years (+30) components like those ? If the price is 8 or 10 $ each , what is the problem ? You are a Mc Intosh owner's and you have to be ready to pay the right price to get original components from official Mc Intosh retailer or from the factory . They are safe sources .

Trying to find less "expensive" components is a risk that I will not take as a pro and I am sure to buy non conterfeit semi conductors

You said :

Q516 = 132203 = MJ4247
Q521 = 132204 = MJ4237

This is not exact

Q516 = 132203 = MJ4248 = no more available replaced by 132229 = MJ15018
Q521 = 132204 = MJ4238 = no more available replaced by 132230 = MJ15019

you like precise answer , you have mine

Do you think McIntosh have bought up the last of those MJ15019/18 Patrice? They are no longer commercially available.

 

[Matt's Dad]

Mackie, I do my own oil changes.... that's why I have 200K on my current vehicle...

why pay out the nose when one doesn't have too?, that's stupid.

 

[Matt's Dad]

Patrice,

Thanks for the answer.

I realize that the original parts are difficult to come by. I thought that maybe someone here had possibly been able to cross reference an available substitute. I guess that is not the case. I am looking for compatible parts which if available from Mouser or digi-key would have been less expensive. No, I do not want to cheapen the performance or longevity of the units I have.

Yes, I realize keeping available stock is not a cheap endeavor, I have purchased items from McIntosh in the past. Gail (she will be retiring in about 8 months after being with McIntosh since 1971) was a great help in my search. The LDRs I got from Mc cost $20 apiece and most other items are in the $10 and up range.

As I said earlier on, I am attempting to have a stock of parts that will aid in the repair of these units further down the road. Both 2255s, the C34V, the 40 year old 2505 & C26 were gone over by Audio Classics and Terry D but that doesn't mean that they wont need repairs in the future.

I was an electronics tech in the Army, and though it has been a few years ago I do know my way around circuitry so that is why I am going down this path. Thanks for your assistance.

 

[petehall347]

just thinking out loud here . i havent fully vetted these so please do so .
all i am thinking with originals being so expensive it might be a good idea to use these for testing only just in case . call them sacrificial if you like .
MJ15016G
MJ15015G

 

[clinic-audio]

Gail (she will be retiring in about 8 months after being with McIntosh since 1971) was a great help in my search. Yes I met her a long long time ago and she was working with Tony (two very nice person )

The LDRs I got from Mc cost $20 apiece and most other items are in the $10 and up range. Please don't forget that MCINTOSH Labs are making business

my best advise would be to buy some replacement set from the factory before they gone be obsolete

 

[jlovda]

As I said earlier on, I am attempting to have a stock of parts that will aid in the repair of these units further down the road.

Somewhere on this forum I read that Mcintosh was not happy when customers would order large numbers of knobs to "update" the appearance of, say, an MR74 to look like an MR78. It defeats the intent of being able to supply a knob for one that was lost or damaged.

 

[kevzep]

Nop

just thinking out loud here . i havent fully vetted these so please do so .
all i am thinking with originals being so expensive it might be a good idea to use these for testing only just in case . call them sacrificial if you like .
MJ15016G
MJ15015G

Nope, not even close....

There is not a TO3 package transistor currently manufactured that fits the necessary spec, you'll find a TO220 package but well, I'm not into butchering!!

 

[Matt's Dad]

Patrice,

I pulled the transistor numbers off of the schematic. Schematic #6 Power Output and Power Guard (Right Channel).

Q516 132203 MJ4247
Q521 132204 MJ4237

So I didn't have the McIntosh replacement #'s. I suppose I could of asked Gail at McIntosh...

 

[Matt's Dad]

Kevin, you are correct, one doesn't want to butcher things...

BUT.... when push comes to shove in 10 years when all the original parts are gone it's going to be either use a TO220 or the unit won't be operational.

One wonders what the original guys at McIntosh would do...

 

[jlovda]

Kevin, you are correct, one doesn't want to butcher things...

BUT.... when push comes to shove in 10 years when all the original parts are gone it's going to be either use a TO220 or the unit won't be operational.

One wonders what the original guys at McIntosh would do...

They would use their employee discount, buy a new one, and butcher up the old one on their basement workbench. It would then go to his grandson's college dorm.

 

[c_dk]

They would buy sample transistors from various vendors and run them through Q/C to find a consistent supplier.

They have always done this.....DOB used to do this with the tubes he would bring to clinics.

They have done that with NTE devices over the last 5 years or so when needed, sometimes using devices that do not cross as NTE says to use......

 

[kevzep]

Kevin, you are correct, one doesn't want to butcher things...

BUT.... when push comes to shove in 10 years when all the original parts are gone it's going to be either use a TO220 or the unit won't be operational.

One wonders what the original guys at McIntosh would do...

Yes I have been in the push comes to shove situation before, and these sort of TO220 in a TO3 hole, can be done in a way that suggests one is not a butcher.

On thing that I didn't research was something in a TO-3P package, there may be something, in fact I can think of one immediately, needs further investigation when i have the time.

 

[clinic-audio]

Patrice,

I pulled the transistor numbers off of the schematic. Schematic #6 Power Output and Power Guard (Right Channel).

Q516 132203 MJ4247
Q521 132204 MJ4237

So I didn't have the McIntosh replacement #'s. I suppose I could of asked Gail at McIntosh...

View attachment 978032

Yes , I know this document #6 but if you take the semiconductors list you have "selected MJ4238 and MJ4248"

this is maybe possible to find only in US market but only for companies ( not final customers ) with a minimum of 250$ the line