I have a MAC 1500 in nice shape. I bought it as an investment, which - as all other true classic 60's gear seems to head for the sky - it remains at about the same value as when I originally purchased it off ebay...
This is the unit that's all tube, except for the phono stage. Worthwhile replacing transistors there, perhaps with modern day low noise equivalents, if they exist as a drop-in?
There's a lot going on tube wise in the FM section, including nuvistors, that I believe run (burn power) even when the input is selected to "aux". I've considered a switch to relieve this section of having to dissipate power when not used, but installing such would probably "molest" the unit from stock form considerably.
Perhaps the best thing to do is just sell it as-is, dead stock - and swallow the fact that it simply wasnt that good of an investment. Currently and for the last 7 years, its just sat in a cardboard box in the closet - no wood cover; that'd be an extra $250 (and an extra shipping parcel; no way they could be shipped together)
Thanks for any thoughts,
This is the unit that's all tube, except for the phono stage. Worthwhile replacing transistors there, perhaps with modern day low noise equivalents, if they exist as a drop-in?
There's a lot going on tube wise in the FM section, including nuvistors, that I believe run (burn power) even when the input is selected to "aux". I've considered a switch to relieve this section of having to dissipate power when not used, but installing such would probably "molest" the unit from stock form considerably.
Perhaps the best thing to do is just sell it as-is, dead stock - and swallow the fact that it simply wasnt that good of an investment. Currently and for the last 7 years, its just sat in a cardboard box in the closet - no wood cover; that'd be an extra $250 (and an extra shipping parcel; no way they could be shipped together)
Thanks for any thoughts,
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I don't understand your logic about nuvistors --- quote -"consider a switch-------having to dissipate power " they use less heater current than normal tubes.
I think you would be making a wrong move either changing them or removing them .
They display a piece of cutting edge engineering in their day and "make " your Mac a unique piece of equipment .
Those early transistors required their own type of bias which is now superseded --don't change them unless you are prepared to change many of the internal components .
I repair very old transistor portable radios installing modern equivalents produces HF oscillation due to gain differences and lower inherent capacitance .
If it is "dead stock " --then repair it to working order at least then you have a working collectable electronic item from that era.
I think you would be making a wrong move either changing them or removing them .
They display a piece of cutting edge engineering in their day and "make " your Mac a unique piece of equipment .
Those early transistors required their own type of bias which is now superseded --don't change them unless you are prepared to change many of the internal components .
I repair very old transistor portable radios installing modern equivalents produces HF oscillation due to gain differences and lower inherent capacitance .
If it is "dead stock " --then repair it to working order at least then you have a working collectable electronic item from that era.
I second this. Leave it completely stock unless it is totally beat to hell. I believe it had germanium transistors in it which would require totally re-engineering it. It would be sacrilegious to do what you suggested. God have mercy on your soul.
I agree the Nuvistors are the best thing going for this piece of equipment. They are a rare find in and of themselves.
If the germanium transistors are not defective, leave them be. OS germanium transistors can be sourced, in the event a problem is present. I'd bet money on McIntosh properly setting the germanium parts up with voltage divider bias and a RC networks between the emitters and ground.
FWIW, I'd take "audiowize" up on the offer to look the unit over.
FWIW, I'd take "audiowize" up on the offer to look the unit over.
Thanks guys! Appreciate this advice.
- There's many tubes on the FM section besides the nuvistors. If I used it, I'd never/rarely use the FM tuner - and thought it's be a shame to incur all those operating hours for nothing. That's where the switch idea came from - but I see the disaster looming with that.
- It'd be fun to visit audiowize and connect with another audiophile in the area, but I am 63 and from what I'm reading these days, I better be careful with myself. (I was just short of typing out an allusion to someone finding this "at my estate sale" in my OP)
- I'll leave it alone. Anyone have an opinion on why this isnt worth 5 - 10K, like I was expecting? Those various Marantz units command that. And they dont even have separate headphone windings on the output transformers. What, McIntosh isnt as "vintage" as Marantz? Isnt in the same quality ballpark? Or is it just like the stock market - price based on whatever traders believe has value at any given moment?
Just curious, as I thought the investment would be a shoe-in at the time, in a "how could anything actually still obtainable in audio be better" way.
- There's many tubes on the FM section besides the nuvistors. If I used it, I'd never/rarely use the FM tuner - and thought it's be a shame to incur all those operating hours for nothing. That's where the switch idea came from - but I see the disaster looming with that.
- It'd be fun to visit audiowize and connect with another audiophile in the area, but I am 63 and from what I'm reading these days, I better be careful with myself. (I was just short of typing out an allusion to someone finding this "at my estate sale" in my OP)
- I'll leave it alone. Anyone have an opinion on why this isnt worth 5 - 10K, like I was expecting? Those various Marantz units command that. And they dont even have separate headphone windings on the output transformers. What, McIntosh isnt as "vintage" as Marantz? Isnt in the same quality ballpark? Or is it just like the stock market - price based on whatever traders believe has value at any given moment?
Just curious, as I thought the investment would be a shoe-in at the time, in a "how could anything actually still obtainable in audio be better" way.
When it comes to die hard vintage collectors, the people willing to pay top dollar, the value is in its being original, all original, not better. If you have an amp with original paper and oil caps and it still works, (for example) it's much rarer and worth far more than a after a recap, even though we all know it would be better to recap it. I'm a tweeker myself so I like it "better" but value is in it's rarity, not in being reworked better. Restored is worth less than the original condition.
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Your right Blaxshep ,in old collectable radios what many did was open up the paper and electrolytic capacitors take out the innards and fit modern replacement then close them back up and refit.
OR there are actually dealers in the UK that have supplies of old original parts .
But I absolutely agree I would want original-original -original.
Look at the vintage car market they go over them like Sherlock Holmes to see if they are all original.
OR there are actually dealers in the UK that have supplies of old original parts .
But I absolutely agree I would want original-original -original.
Look at the vintage car market they go over them like Sherlock Holmes to see if they are all original.
Nuvistors use nearly the same heater power as the conventional tube you would use to do the same job. They are much smaller and run hotter. They derive from military use research and are VERY robust and long-lasting. They also resist neutrons, in case you expect atomic war. Leaving them running does no real harm. I see no reason to replace Nuvistors unless proven bad. (If they have been hot 24/7 for 55 years, or shot-up into space, there could be sick ones.)
The transistors in the 1500 are Silicon. You don't have to guess: read the service manual and look-up the part numbers.
http://www.tubebooks.org/file_downloads/McIntosh/MAC1500_service_manual.pdf
https://www.mouser.com/datasheet/2/149/FairchildSemiconductor_16142054259057-795640.pdf
https://pdf1.alldatasheet.com/datas...1723UORlHDyRHOIpa/1XXyxeohdMIH+/datasheet.pdf
The circuit was ahead of its time, is utterly stable, and Mac used the same circuit for many years. The only potential issue is some fool pushing hot line level into the Phono jacks. Then the first transistors may have breakdown damage and excess hiss. Even this does not beg for replacement: swap the first and second transistors. They are same-type, the 2nd won't be sick, and a hisser in the second spot won't matter.
Leave it alone!!
> why this isnt worth 5 - 10K
Not many people have had $10K burning their pockets these last 20 years. Guys who went broke in the down-swings have been unloading once-sexy gear to buy groceries. It does not take much excess Supply to collapse Demand (and prices).
The transistors in the 1500 are Silicon. You don't have to guess: read the service manual and look-up the part numbers.
http://www.tubebooks.org/file_downloads/McIntosh/MAC1500_service_manual.pdf
https://www.mouser.com/datasheet/2/149/FairchildSemiconductor_16142054259057-795640.pdf
https://pdf1.alldatasheet.com/datas...1723UORlHDyRHOIpa/1XXyxeohdMIH+/datasheet.pdf
The circuit was ahead of its time, is utterly stable, and Mac used the same circuit for many years. The only potential issue is some fool pushing hot line level into the Phono jacks. Then the first transistors may have breakdown damage and excess hiss. Even this does not beg for replacement: swap the first and second transistors. They are same-type, the 2nd won't be sick, and a hisser in the second spot won't matter.
Leave it alone!!
> why this isnt worth 5 - 10K
Not many people have had $10K burning their pockets these last 20 years. Guys who went broke in the down-swings have been unloading once-sexy gear to buy groceries. It does not take much excess Supply to collapse Demand (and prices).
Attachments
#1 It's not that rare.
#2 It doesn't have blue meters and green backlit glass.
#3 The solid state preamp section.
Are there any vintage tube receivers worth $5000-10,000?
Are there any vintage tube receivers worth $5000-10,000?
An original 1940,s Williamson tube power amplifier ?
Vintage Hi Fi museum. Quad 22 and 202 valve amplifier. Leak, Rogers, Trio tube amps. Williamson papers
An original 1940,s Williamson tube power amplifier ?
Vintage Hi Fi museum. Quad 22 and 202 valve amplifier. Leak, Rogers, Trio tube amps. Williamson papers