McIntosh MAC-1700

Discussion in 'Stereo Receivers' started by W5HRO, Oct 25, 2017.

  1. W5HRO

    W5HRO Administrator

    Just bought a pretty much mint condition McIntosh 1700. Only bad thing is I have to drive down near LA this weekend to pick it up because the guy wont ship it. It's the second later version with two sets of speaker output connections and was purchased new in 1969 by the guys family member.

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  2. W5HRO

    W5HRO Administrator

    Got lucky, the guy drove up from near LA to bring the receiver too me since he was going to visit some friends up near San Mateo tonight.

    Right now just using it with headphones before putting it into the cabinet. The bass response is unbelievable :icon_thumbup:

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  3. W5HRO

    W5HRO Administrator

    The guy also brought me the bag of parts that were recently replaced. He had someone go through it to check everything and they replaced the old Mallory paper tubular caps. These are the same type of caps you have to replace in the National 300 and 303 ham receivers for example because they all leak due to their age.

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    There is also an LED lamp upgrade kit you can buy for these things.

    P.S. The guy is a real McIntosh nerd and he said one of his family members was part owner or something in the original McIntosh company.
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  4. W5HRO

    W5HRO Administrator

    I found some pictures of another old MAC-1700 which shows where those white tubular Mallory paper caps are. Most all of them are on the boards except like one or two. I'm glad the guy had them replaced in mine so I never have to worry about it. When I have the chance I will replace the big supply filter cans, but right now they are still good.

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  5. W5HRO

    W5HRO Administrator

    Been busy cleaning up the room/shack today. It got pretty messy over the past year and a half.

    Have to make room for a big-ass pair of speakers :mrgreen:

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  6. W5HRO

    W5HRO Administrator

    One thing the guy told me and he was right because I found it mentioned here on the net. The volume knob was integrated with the power on/off switch so when you turned it all the way to the left it switched it off. He said most all Mac 1700 users just use a power strip with a switch to turn the receiver on and off instead to save the switch. The one on this 1700 still works fine, but it would eventually fail if I started using it.

    https://classicreceivers.com/mcintosh-1700

    "While McIntosh was known for its build quality and reliability there are a few idiosyncrasies related to these units. The power switch was integrated into the volume knob. Many of these switches have long since failed. Replacement parts are not available so many owner's bypass the switch and use an external switch such as a power strip to turn the unit on or off."

    Anyway, I ran down to the store yesterday and picked up a cheap Monster power strip with the switch for now so I will just use it to power everything on and off.

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  7. W5HRO

    W5HRO Administrator

    Another thing I also noticed Sunday morning after I got up and turned the receiver on was ever so often I would here that same hummp, hummp, coming from inside of the receiver when my line voltage surged here in the room/shack. When I first turned it on I left the volume turned down all of the way for the first 30 minutes and noticed that occasional hummp. I was hearing the same thing with my big Astron power supply last winter.

    Anyway, our line voltages surges here all of the time so I bought one of the line regulators below just for the Mac 1700 receiver. These things are dirt cheap and after reading the reviews people say they work. If they do I will buy a couple more for the ham gear and my Mac computer as well.


    600W 1200VA Stabilizer Series 6-Outlet Automatic Voltage Regulator

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  8. W5HRO

    W5HRO Administrator

    I received the automatic voltage regulator yesterday and it seems to be working. It's a Buck-Boost regulator and it keeps going into buck mode. I've been watching it tonight and the top led keeps coming on every once and a while which means buck mode. What that means is my line voltage keeps surging up too high so it has to buck it down which is what I need. The relay clicks as it goes in and out of buck mode.

    I need to buy a few more of these to use all over the house, because they do seem to work. It's a quick, cheap and dirty way to do it. They make a heftier 1000W model too so I will probably buy those instead.
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  9. W5HRO

    W5HRO Administrator

    Update: I put a voltmeter on the output of the regulator last night and my line voltage when normal is around 122V. When it creeped up to about 130V the buck was kicking in, but it dropped the line voltage down to 114V which is fine, but I don’t think the box is good for 600W or even 300W which may have been why. It’s a cheap one made in China. It was only $20 so it wouldn’t surprise me. My Mac 1700 receiver draws about 270W and the regulator was getting a bit warm.

    Anyway, I read the reviews on the bigger 1000W model and it got slammed. The main compliant was the cases were broken on arrival due to the weight and poor packaging and they come up in boost mode often when they shouldn’t. So, as a result I decided to look around for a better one and found it. APC makes a 600VA and a 1200VA model and they even have an input voltage switch on the back so you can adjust it. I decided to order one of the 1200VA models and use it for the Mac receiver instead because it’s about the same price as the 1000W Chinese model which I doubt is anywhere close to 1000W. If this APC works them I will just buy these instead for my other stuff. I can also just use the switch on front to turn the Mac 1700 and everything on and off instead of using that power strip.

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    I'll probably use the 110V position if it runs cool.
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  10. W5HRO

    W5HRO Administrator

    McIntosh :mrgreen:

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    You can probably see the APC regulator on the bottom and it works fine. I have to run it with the switch in the 120V position because it stays in buck mode constantly when it's on the 110V position which makes sense I guess. Anyway, 50 times better than the cheap $20 Chinese one :icon_thumbup:
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  11. W5HRO

    W5HRO Administrator

    I decided a while back to set the input switch on APC regulator to where it just stays in Buck mode all of the time. That way the voltage is always regulated and it only switches to normal mode for a second or two on very rare occasions. With it set to where it stayed in the middle normal position it was switching to Buck mode too often with the very rare switch to Boost mode. When that happened the audio level would go down and then back up again just slightly because of the decrease then the increase in line voltage. If I was to ever start making recordings that would be a noticeable volume level change.

    Anyway, making it stay it Buck mode doesn't seem to make the APC unit get hot or anything because I guess it's designed to handle it and it will also keep the filament voltage down on the tubes and the lamps in the receiver which is a good thing too. It's either using the $45 APC unit or buying a $2,500 to $8,000 line conditioner made for media systems like the below ::)

    MPC-1500
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