MAC 1900, 1700 any good?

[seacliffe301]

I prefer the 1700 over the 1900. I found the one below in pretty much mint condition just a few months ago. It's 40W per channel. The 1500 is all tube, the 1700 is a hybrid, and the the 1900 is all solid state. Never did like the push-buttons and those awful Bass and Treble slider controls on the front of the 1900.

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That's a nice find! Cabinet, manuals & near mint. It doesn't get any better than that. Congrats.

BTW, those units are so striking, I alternate mine between in cabinet and out. Usually about once a year or so I'll swap it out. I'm due to put it back in the cabinet soon, LOL.

 

[w5hro]

That's a nice find! Cabinet, manuals & near mint. It doesn't get any better than that. Congrats.

BTW, those units are so striking, I alternate mine between in cabinet and out. Usually about once a year or so I'll swap it out. I'm due to put it back in the cabinet soon, LOL.

It came from someone connected to the original McIntosh company, some family member. The guy I got it from said it belonged to his uncle whom it was made for in 1968 I think.
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[w5hro]

Regarding the spec on wattage, like all Macs, it’s underrated. My unit always produced a healthy 62 w/ch at the old Mac clinics. I use it as a second system to this day.

The specs for the 1700 are...

40 watts RMS into 4 ohms or 8 ohms.

80 watts RMS monophonic into 4 ohms or 8 ohms.

30 watts RMS into 16 ohms.

60 watts RMS monophonic into 16 ohms.

A lot of it depends on your speakers (the load). It's probably 40W into 8-ohms and a bit higher into 4-ohms.
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[62caddy]

The 40 wpc spec is McIntosh's rating but bench tests at or above 60 wpc under 1% THD (both channels driven) is not uncommon for the MAC1700 (8 ohm)

- Never heard of any Mc receiver designed for single channel mono operation- either bridged or mono parallel.

 

[seacliffe301]

The specs for the 1700 are...

40 watts RMS into 4 ohms or 8 ohms.

80 watts RMS monophonic into 4 ohms or 8 ohms.

30 watts RMS into 16 ohms.

60 watts RMS monophonic into 16 ohms.

A lot of it depends on your speakers (the load). It's probably 40W into 8-ohms and a bit higher into 4-ohms.
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My load is at 8 ohms, as was the load on the bench test. McIntosh notoriously underrated their power performance. I’ve owned many different Mac amps over the decades and they all displayed this characteristic.
My 2155, which is rated at 155w/ch at 8 Ohms clocks in right around 200w/ch.
Value added in my book.

 

[62caddy]

The "30 wpc" MAC1500 is usually only good to the low 30s so not a lot of margin on that model. Might explain why its power range is given as 30-20k instead of 20-20k. In reality, the MAC1700 is at least twice as powerful.

 

[w5hro]

The specs came from the manual...



I actually wanted the 1500 because I prefer all tube type, but then I came across the 1700 and couldn't resist. The only thing that would have made the 1700 better is if they had used a tube preamp stage instead of SS. It's a shame they converted it to SS. The SS finals are fine though.
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[62caddy]

I have no idea why they're providing a monophonic specification for a unit not designed for mono operation.

MAC1500 has tube tuner and power amplifier sections only - preamp section is SS- if it's any consolation.

Someday I'd like to find a mint MAC1700 to go with my 1500. Several years ago there was a flurry of exceptional 1700s on the 'bay (some even with original packaging) all at very reasonable prices. I'm sorry I didn't act when I had the chance.

 

[w5hro]

MAC1500 has tube tuner and power amplifier sections only - preamp section is SS- if it's any consolation.

Oh yeah, that's right. I guess picking the 1700 was the better choice.

Someday I'd like to find a mint MAC1700 to go with my 1500. Several years ago there was a flurry of exceptional 1700s on the 'bay (some even with original packaging) all at very reasonable prices. I'm sorry I didn't act when I had the chance.

The guy I got the 1700 from had it on eBay and Craigslist both. As soon as he saw the interest was high he jacked the price way up. It belonged to his uncle whom supposedly had a connection to McIntosh. He either worked there back in 60's or was a family member of someone there. I forget exactly what he told me. Anyway, he actually drove up to my house from down south and delivered it which was nice, but I think he was also worried about getting paid since I used PayPal. He probably didn’t want to risk it getting damaged via shipping, etc. He also didn’t want to power it up using the on/off switch on the volume pot and told me why. It still works, but I use the switch on my APC regulator to turn everything on and off instead since those switches are prone to fail with no replacement available. Heck, I looked in one of their parts catalogs from about 1977 and they were no longer available even back then.
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[TSmith8605]

I have no idea why they're providing a monophonic specification for a unit not designed for mono operation. . .

The only thing I can think of is that the amp's power is limited by the common (to the two channels) power supply and when one channel has no signal, all the PS power goes to the active channel and that amplifier can use all the power to double it's output. But not sure that makes sense as the output voltage would be clipped at the same level regardless of how much additional current is available for the unshared PS.

I did have an experience with this in the '70s when I and a roommate had identical Kenwood integrated amps with pre-out/main-in connections. For the stereo speaker pair (B&O 5700) we ran one channel from each amp from one of the pre-amp sections (leaving an idle channel in each amp) and the increase in power was very noticeable (vs running either amp alone with both channels active). We had no measurements to show exactly how much more power was available.

 

[w5hro]

The 1700 does have the Stereo/Mono switch on the front, but I haven't gone through the schematic to see was the switch is actually controlling. Maybe when switched to mono the power comes up a bit. It depends on how they are doing it though.
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[62caddy]

The only thing I can think of is that the amp's power is limited by the common (to the two channels) power supply and when one channel has no signal, all the PS power goes to the active channel and that amplifier can use all the power to double it's output. But not sure that makes sense as the output voltage would be clipped at the same level regardless of how much additional current is available for the unshared PS.

My thought was perhaps a holdover from the old days when stereo amplifiers used to be rated as a sum of both channels (later prohibited by law).

I'll have to check the manual of my MAC1500 again to see if they did the same thing.

Oh yeah, that's right. I guess picking the 1700 was the better choice..

My opinion that for the money, it's every bit as good as the MAC1500. However I'm sure I don't have to point out how popular vintage tube equipment is nowadays, and is reflected in the respective selling prices of tube and SS equipment - rightly or wrongly.

The guy I got the 1700 from had it on eBay and Craigslist both. As soon as he saw the interest was high he jacked the price way up. It belonged to his uncle whom supposedly had a connection to McIntosh. He either worked there back in 60's or was a family member of someone there. I forget exactly what he told me.
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While its still fresh in his mind, I would check with the seller and write down anything he is able to tell you about the unit's history of ownership. This is sure to be of importance to collectors of McIntosh.

Using a power controller to spare the use of the on/off switch is an excellent idea and highly recommended.

 

[w5hro]

My thought was perhaps a holdover from the old days when stereo amplifiers used to be rated as a sum of both channels (later prohibited by law).

I thought in the old days when they said watts per channel that it meant each channel separately until they started adding the two together in modern times to make it look better? If I see a new amp today and it’s says 80W then to me they really mean 40W per channel. They just add them together via bogus advertising claims.

The other thing is even McIntosh used the term RMS incorrectly. There is really no such thing as RMS power, it's really Average power. You have RMS voltage, but not power. It's actually a tricky subject today because there is some new technology that can come close to producing an actual RMS type of power measurement, but it's (R)MS power. The problem is most of the meters on the market today claim to be RMS, but they not very accurate because they simple cannot measure RMS period! Be careful if you have one of those bogus meters. Nine times out of ten the meter is reading too high and is not accurate.
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[62caddy]

I thought in the old days when they said watts per channel that it meant each channel separately until they started adding the two together in modern times to make it look better? If I see a new amp today and it’s says 80W then to me they really mean 40W per channel. They just add them together via bogus advertising claims.
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Back in the early days of stereo, that's how a lot of manufacturers did it. It was even against the law for manufacturers to list the model number of stereo amplifiers and receivers to be the sum of both channels; ie a 50 watt receiver could not be given the model number "XB100". I recall a Carver amplifier many years ago with the model number containing "400" with a "201 wpc" rating. (Or something very similar - this was some time ago and my memory is not all that it was.)

Given Bob's sense of humor, I would have expected no less.

I don't recall whether any such provisions applied to mono amplifiers.

 

[EyeGee]

Kind of miss my mono switch from the 4100 I replaced with a 4300V. one can't have everything, can one?

 

[TSmith8605]

My thought was perhaps a holdover from the old days when stereo amplifiers used to be rated as a sum of both channels (later prohibited by law).

I'll have to check the manual of my MAC1500 again to see if they did the same thing. . .

Well, the MAC 1500 manual I have says:

"POWER OUTPUT: 60 watts continuous, 30 watts per channel, 85 watts total music power (I.H.F. Standards)."

The service manual I have has this identical wording.

No mention of "monophonic" power which one would assume is different than "total" power.

While we're at it, my MAC 1900 op manual says:

"POWER OUTPUT: 55 RMS watts continuous per channel into 4 or 8 ohms both channels operating 20 Hz to 20,000 Hz.

30 RMS watts continuous per channel into 16 ohms both channels operating 20 Hz to 20,000 Hz."

 

[62caddy]

Yup - good 'ol pre 1974 FTC power ratings of the Wild West. Although McIntosh's were realistic; the vast majority of others being grossly exaggerated.

Even the well regarded Fisher tube receivers (7591 x4) models would barely qualify as 20wpc units by McIntosh standards, yet were routinely marketed as "60 watt" receivers (or something close). Also, McIntosh always rated for both channels operating simultaneously unlike others providing another avenue to cook the books. "IHF Music Power" was another example of the misinforming jargon used to inflate power ratings as well.

 

[w5hro]

Well, the MAC 1500 manual I have says:

"POWER OUTPUT: 60 watts continuous, 30 watts per channel, 85 watts total music power (I.H.F. Standards)."

The service manual I have has this identical wording.

No mention of "monophonic" power which one would assume is different than "total" power.

While we're at it, my MAC 1900 op manual says:

"POWER OUTPUT: 55 RMS watts continuous per channel into 4 or 8 ohms both channels operating 20 Hz to 20,000 Hz.

30 RMS watts continuous per channel into 16 ohms both channels operating 20 Hz to 20,000 Hz."

That's exactly what the 1500 and 1900 manuals say and in that same format, but not the 1700 manuals. Even the 1700 service information manual says the below. What I posted before was from the owners manual.

POWER OUTPUT
40 watts RMS continuous per channel with both
channels operating simultaneously into 4 ohm or
8 ohm loads, 80 watts RMS continuous monophonic,
30 watts RMS continuous per channel with both
channels operating simultaneously into 16 ohm
loads, and 60 watts RMS continuous.

You can find the 1700 owners and service manuals on hifiengine for free pdf download.

While its still fresh in his mind, I would check with the seller and write down anything he is able to tell you about the unit's history of ownership. This is sure to be of importance to collectors of McIntosh.

The guy gave me some ladies name there back when he delivered the receiver and said I could call her or someone else and that the serial number was on record on who it belonged to. I should probably do that sometime soon.

He also said the 1700's service information manual was impossible to get today and that he even sent McIntosh a copy of the one I have because they didn't even have one on file anymore. The lady ask him to send them a copy which he did.
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[mrz80]

Which version of the 1700? There were two flavors - one with a single loudspeaker on off switch and set of speaker terminals, and one with two switches (and the loudness compensation switch moved to a knob coaxial with the balance knob) and two sets of speaker terminals.

 

[w5hro]

Which version of the 1700? There were two flavors - one with a single loudspeaker on off switch and set of speaker terminals, and one with two switches (and the loudness compensation switch moved to a knob coaxial with the balance knob) and two sets of speaker terminals.

It's the 2nd version with the colored speaker push terminals on the back with the loudness switch in the center of the balance knob. If you go back and look at the pics I posted they show all that.
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