McIntosh power transformers

kimmo

Member
Power transformers in service manuals of classic 70´s solid state Mac´s like 2105, 2125 seems to have dual primaries connected in parallel. Owners manuals and service manuals specify them only capable for 120VAC operation.

Is it possible to rewire them for 220-240VAC operation by connecting primaries in series... or is there some other reason for above mentioned specification?

Best Regards

Kimmo
 
Register to hide this ad
MC INTOSH power transformers

The factory did not produced power decals in the same manner

Some are with double primary , some other not .It is like that .

This is because voltage convertion was normally reserved to official distributor and not for customers who knows (internet) how to proceed .

Actual production is made for the specific country by the factory and very soon it will no more be possible to make any voltage convertion on US unit for Europeen market , units will not work at all !

To answer to your question : Mcintosh NEVER give anywhere voltage convertion for his units

And to be more precise in my answer : don't think that making voltage convertion on Mcitnosh units is easy by simply connecting two primary windings in serie ! you will be very surprised one day !

example : Be very carefull (again) because some early MC2505 are not possible to convert ! only one primary winding !:scratch2:
 
That is the idea of the parallel primary windings 117VAC/234VAC, HOWEVER, ALWAYS get the factory service information for changing voltage.
Changing the primary windings is only part of the conversion....

I have done voltage conversions on a few Mc's now, and its not as straight forward as you would think.....
Although the power-amps are the easiest to do......
 
I know you have to change the fuse as well as the power cord. Quite awhile ago there was a thread on this subject. Living in the US, I've never had to worry about it.
 
It ain't easy having vintage MC outside the U.S :)

I had both my MC250 and my MC2100 (early production - 25WXX serial) rewired to 230V by a tech. He didn't mentioned it to be complicated...
 
It ain't easy having vintage MC outside the U.S :)

I had both my MC250 and my MC2100 (early production - 25WXX serial) rewired to 230V by a tech. He didn't mentioned it to be complicated...

No, it's not complicated for a tech, thats the point.

There are a lot of well meaning DIY'ers here and this is where the trouble can start.....

I have seen it. Did you know that in a C32 for instance the soft start relay is driven straight from the mains which is rectified and is then driven with 110VDC.
If you just change the primary windings on a C32 transformer, you then have 230VDC going though a circuit designed for 110V, it may work for a while, but when it fails, it will do so in spectacular fashion....with smoke, and component damage not to mention burning out the relay...

Then there are the RF suppressors which are 150VAC, these need to be changed to 500VAC.....

So don't assume its as easy as just changing the primary windings to convert your McIntosh to 230V.....!!!! Be Warned!!

Another example.....the C40 pre-amp, it has mains going to a memory circuit even when the unit is off so it can remember which position the input selector and such are positioned, it you just change the primary winding and plug it into the mains, you will blow up the memory circuit.....

ALWAYS get the McIntosh service information before any voltage conversion...
 
No, it's not complicated for a tech, thats the point.

There are a lot of well meaning DIY'ers here and this is where the trouble can start.....

I have seen it. Did you know that in a C32 for instance the soft start relay is driven straight from the mains which is rectified and is then driven with 110VDC.
If you just change the primary windings on a C32 transformer, you then have 230VDC going though a circuit designed for 110V, it may work for a while, but when it fails, it will do so in spectacular fashion....with smoke, and component damage not to mention burning out the relay...

Then there are the RF suppressors which are 150VAC, these need to be changed to 500VAC.....

So don't assume its as easy as just changing the primary windings to convert your McIntosh to 230V.....!!!! Be Warned!!

Another example.....the C40 pre-amp, it has mains going to a memory circuit even when the unit is off so it can remember which position the input selector and such are positioned, it you just change the primary winding and plug it into the mains, you will blow up the memory circuit.....

ALWAYS get the McIntosh service information before any voltage conversion...
May I make a comment here? Everyone is saying bad, bad, bad but no one says exactly what has to be done and let the owner make the decision. However, the owner never stated what model he has. Is this a curiosity question or does he really want to do it?
 
May I make a comment here? Everyone is saying bad, bad, bad but no one says exactly what has to be done and let the owner make the decision. However, the owner never stated what model he has. Is this a curiosity question or does he really want to do it?

No one said anything like BAD, its just a warning, simple as that, voltage conversions are not always as simple as changing the primary winding on the power transformer.....thats the point, I am speaking from experience, as I have done a fair amount of voltage conversions.....
Go on then, don't change the RF suppressors....see how long they last at twice the voltage they are designed for.....

Damage to the unit can happen if you do not follow the procedure, and at the end of the day, knock yourself out, but you have been warned.....(not you specifically being a US resident).
I have converted, C32, C40, MC250, MR78, MR80, MC2205, MC352.....So I know what I am talking about to some degree...

What needs to be done, is the service bulletin needs to be referenced.....thats what needs to be done...
 
Mc Intosh power transformers

Hello JOHN

May I make a comment here? Everyone is saying bad, bad, bad but no one says exactly what has to be done

How to start my answer ...?

When I was making service for MCINTOSH in France (a long time ago) , I give my word to the president of the factory that I will never give the voltages instructions for MC INTOSH units (all models included) .
I will not do it today !
Since,the president of MCINTOSH lab has changed but not my word .
"no one says exactly what has to be done " of course John if I say everything about voltages convertions I will not respect my word and this is not possible !
 
Hello JOHN

May I make a comment here? Everyone is saying bad, bad, bad but no one says exactly what has to be done

How to start my answer ...?

When I was making service for MCINTOSH in France (a long time ago) , I give my word to the president of the factory that I will never give the voltages instructions for MC INTOSH units (all models included) .
I will not do it today !
Since,the president of MCINTOSH lab has changed but not my word .
"no one says exactly what has to be done " of course John if I say everything about voltages convertions I will not respect my word and this is not possible !

Precisely Patrice......:thmbsp:
 
McMagic

I do not understand this back magic, or should I say McMagic concerning primary wiring. There is only power switch, fuse, 2 thermal cutouts and 2 varistors in 2105 and 2125 primary side... even switch supresssion cap is missing. If these can not be scaled for 230 VAC operation... I should be on electronics for dummies forum.

Actually my only concern should be if I can trust markings on transformer, that has schematic with dual primary printed on cover, as you say that also single primary power transformers have been used? It is bad thing if I will find that transformer with dual primary schematic on case appears to have only single 117VAC primary.

Best Regards

Kimmo
 
I don't think it's so much black magic as it is a concern from the manufacturer that the unit is converted properly. As kev and Patrice point out, there's a lot more to such a conversion than meets the eye. Why not take your unit(s) to a qualified technician and have it done correctly?
 
MC INTOSH power transformers

Hello kimmo

I do not understand this back magic

And do you understand : "Preservation of interest" ?

There is no black magic , this is simple : if you have official distributors worldwide how can you protect them from double market ?


What can you do against some sellers offering 110V units from the US market and sending them worldwide ...? The only way is to preserve the voltage convertion is to keep them away from "spy" and this ways units STAY in 110V without any warranty !

Official distributors have all the voltages convertions sheets with all the component needed to be replaced , the way the new power transformer connections's should be made (with colors of wires to avoid any missphasing) . I can tell you also that some units need a new power transformer and you can't get it from the factory if you are not allowed to buy it .

And to preserve their interest they will not give you the complete instructions to convert your unit whatever it is a very old unit !

Very easy to understand

Where are you ?
 
I suspect some of the responses acting as a caution do so reason. If it were say a Monarch (no insult to the company, it just was what came to mind) then likely most would say, what the heck, try it and see. If it blows up, it is not a high dollar unit and you'd less likely be venting you frustrations as to the advice given. A McIntosh is a horse of a different color, though. Also, as pointed out due to their design it may impact other circuits and hence just reworking the power supply not be sufficient.

Now,.I will ask the stupid question: If you need 220-240volts, why not just by a stepdown inverter to reduced the higher voltage to that which is optimal for the Mc. This is a very common practice and likely safer, easier to find and less expensive than going the route you are thinking with less chance of catastrophic results?
 
I do not understand this back magic, or should I say McMagic concerning primary wiring. There is only power switch, fuse, 2 thermal cutouts and 2 varistors in 2105 and 2125 primary side... even switch supresssion cap is missing. If these can not be scaled for 230 VAC operation... I should be on electronics for dummies forum.

Actually my only concern should be if I can trust markings on transformer, that has schematic with dual primary printed on cover, as you say that also single primary power transformers have been used? It is bad thing if I will find that transformer with dual primary schematic on case appears to have only single 117VAC primary.

Best Regards

Kimmo

There is no black magic as stated......I am not sure why you are saying that...

The issue as I see it, is that you'll get away with doing a conversion on your amplifier as the older amplifiers are actually easy.....
BUT then when you decide you want to buy something like a C32 or similar, then the conversion is not straight forward, and without the service information you will damage the unit....

The reason the information is not readily available, and not in the user manual, is because McIntosh are trying to protect their local dealers.
They do not want you buying units cheap from somewhere else in the world and bypassing your local dealer for a bargain.

Now, this really is only relevant when everything is new of course, so in the case of a MC2105 etc etc they probably don't care now because they have a whole new market to protect....
But the people holding this information signed contracts stating they will not share the information, and Patrice (clinic-audio) is a man who stands by the agreement he made, he is a man of integrity...
I am sure if you try hard enough you could find the information.....

In my opinion, there are good and bad sides to this.....the good side is that you have the full support of McIntosh with warranties and such, buy from overseas and then need factory support? Forget it!!
The Bad side is, and you'll know this living where you do, is that if you live outside the US, it is very limited in terms of what you can buy from a dealer if you can even find one.....In New Zealand there is a store who advertises McIntosh like they are a dealer, but when you go in there to buy something or ask if they can get something in, they say they are unable to buy stock at the moment?? or there's a new shipment (which never seems to turn up)....Ridiculous...(although, they did happen to have a MC452 when I wanted one, not sure how they got it, AND I have no warranty with it either)
I don't know, maybe it is different in Europe......

What they do now (since 2012) is make the units region specific, so the units made in the USA are 120V only, they cannot be converted.
This, to protect their local dealers, well thats great apart form the fact the dealer network is non existent in this part of the world, so guys like me who want to buy new McIntosh cannot actually buy it because there is no dealer here, and what is McIntosh doing about it?
Nothing I'll bet.....
I tried to buy from Australia, but the dealer wouldn't sell to me because of dealer rules stating they cannot sell outside their area...
So what am I supposed to do??? I want to buy McIntosh, but because of their dealer rules and trying to protect the dealers, they are actually losing customers in this part of the world....

A friend of mine wanted to buy a MC207 and a MX151, but there's nowhere to buy one except the USA, and the voltage cannot be changed, he doesn't want a 120V unit.....Or Australia, but they won't sell to him.....ARRRGGGG!!!!
So now he is going to buy something else.....

I think its a stupid system McIntosh are running, in my opinion.....

So when I bought my C48 and MEN220, I had to buy from the USA, and have to put up with 120V units, second hand, no warranty, and limited resale, guys down here don't want 120V units, the first question asked when you are trying to sell these things down here is "has it been converted to 230V?"...
I have a stepdown transformer, and I am not that bothered about the units being 120V, but I would rather they weren't.....

I'll bet I'll never know when firmware and software updates are available, I am stuck with the way the unit is now....

I complained to McIntosh about the dealer situation here, and never heard back form them.....Maybe they feel market down here is so small its not worth it...
BUT, I know a lot of HIFI nuts that love my system and want to buy Mc but can't....

I really wish Mc would do something about this......

Now,.I will ask the stupid question: If you need 220-240volts, why not just by a stepdown inverter to reduced the higher voltage to that which is optimal for the Mc. This is a very common practice and likely safer, easier to find and less expensive than going the route you are thinking with less chance of catastrophic results?

Its not a stupid question, this is exactly how I run my C48 and MEN220....I have a step down transformer....
It is a pain in the ass having to do this though, transformer hum, and the dirty big horrible transformer sitting on the floor..but I have no other option.....Its like American cars here....

And remember, NO factory support should something go wrong....I doubt I would have any support from McIntosh with my MC452 because I bought it from a store which wasn't actually an authorised dealer.....I know they weren't a dealer because they had no idea how to put the MC452 back in the box, I had to show them!!! Ridiculous!!

If I want to sell these units to upgrade or whatever, they are really hard to sell because guys here don't want 120V units....its the first question asked....
Just like American cars here being left hand drive...the first thing you look for is the car being converted to right hand drive....
Left hand drive cars are very difficult to sell here.....

Anyway, thats my take on the situation.......
 
Last edited:
117v mains vs 234v

Caution is needed here in Finland. 234VAC mains network is far superior compared to 117VAC mains, as line regulation is 100% better for similar amperage if similar gauge wiring is used. Actually line regulation is 200% better for similar gauge wiring, as only 50% amperage is needed. However downside is that primary wiring must also be made to higher standard.

It was almost impossible to make US made high end gear to meet FI electrical safety regulations for several reasons. Isolation distance of 110V mains transformer bobbin was not enough for 220 VAC operation, so dual primary transformers were no good enough for 220V operation. 3 prong double insulated mains leads were required quite early here. I have refurbished ARC SP6 and CJ Premier 7B and they do have mains lead that do meet this requirement, but green wire of SP 6 is connected only to mains outlets. Premier 7B green wire is connected only to mains filters insulated from chassis. Such connections are true safety hazard and 100% illegal here.

Dual pole mains switches were also needed to meet FI standard quite early, my 1993 vintage 240V UK spec ARC SP14 does have single pole switch... I have not checked if it is 125 or 250V one as this seems to be place where i have found quite often 125 V rated switch in original European model. Drop, durability and moisture resistance tests practically trashed tested gear, so testing was quite expensive.

Later Nordic countries made their safety regulations quite similar, it was more cost effective to produce and test products for our markets. But most likely this was not enough, as I do not remember that I had seen one ARC, Krell, ML, CJ with FI or Nordic approval marks. Isolation transformers were quite often used in industrial installations, as it was possible to use FI approved power supply (transformer) to meet regulations. For Mc this is not suitable solution, as this will make power supply regulation worse. CE regulation has made things now easier, even from safety standpoint safety is not as good as in late FI or Nordic approval days.

Having made few voltage conversions, I would say that 110V transformer bobbins have not caused troubles. 125V rated switches have also operated without problems. I suppose that situation might be different in tropical climate. Properly grounded mains leads will not make old gear fool proof, but makes safety hazard less obvious.

We do now have official McIntosh distributor here, but no service center does carry we service McIntosh here sign. So, if I need twist lock capacitor or obsolete semiconductor for 60´s to 70´s Mc... I am on my own or get advice to use google. Consequently I would say that it should be fair to provide service manuals like ARC, Harman Kardon or Quad that do have clear voltage conversion information. It is very unlikely that ARC, H/K and Quad engineering is so much better, that they only can give detailed information.

There would always be areas where it would unlikely find official distributor for say McIntosh. If person moves to such place or buys such gear from other part of world (new or used gear) I would not say "shame, shame, shame... you should be on your own... why did you move, you should wait until someone begins to distribute our gear and buy new one.

I have tried to learn something about history of audio. I have restored tube gear like ARC D76A, CL60, SP3a, SP6C, SP14, Conrad Johnson Premier 7B, Premier 11A, EAR509, Quad 22,II,FM1 and recently I have restored somewhat lesser models like H/K Citation 11,12,15, Quad 240,34,405 and I thought that trying some early solid state McIntosh would be fun, even most likely results would be categorized do be these lesser models variety... but if everything is so complicated... is it worth to try?

Best Regards

Kimmo

PS enclosing picture 75 kg pile of restored premplifiers
 

Attachments

  • DSCF0119.jpg
    DSCF0119.jpg
    65.9 KB · Views: 33
Last edited:
MC INTOSH power transformers

Hello Kimmo

If person moves to such place or buys such gear from other part of world (new or used gear) I would not say "shame, shame, shame... you should be on your own... why did you move, you should wait until someone begins to distribute our gear and buy new one.


I think you are not well informed ...
For example : if a French owner's of MC INTOSH product is living and working in New york and after spending 15 years in USA for a french company , if this man go back to France to retire he can call the factory and the MC INTOSH factory will make (charged) the full voltage convertion for France . This is normal because this bought has not been made to double cross anyone .... And also becase the factory do that , but again they will not do it for actual products bought last week ..

If you need help for components for old hifi equipment send me a PM :thmbsp:
 
Back
Top Bottom