Marantz 2225 measured power output - surprise!

[RobHolt]

Bought a set of Mission Cyrus speakers recently rated at 4 ohms.
These really are a nominal 4 ohm load since they use two bass units running parallel and the minimum measured impedance is 3 Ohms in the mid-bass area. So likely to be amp fussy.

With that in mind I swapped out the sweet little Pioneer SA500A I'd been running successfully with some Quad ESL 57s and looked at my collection of vintage kit for something better suited to 4 Ohm drive.
Before doing so I selected my 2225 and thought I'd run some basic bench tests - power into 4 & 8 Ohms (both channels driven) and also response and tone plots.

Well, with a true RMS meter and scope attached I got 35wpc just before clipping into 8 Ohms, and a really very respectable 48w into 4 ohms. That's superb for a 25wpc rated receiver.

Quite the dark horse of the 22xx family, the little 2225.
Lovely sound, uncluttered internals so easy to service, runs cool, and good power delivery.
The FM tuner is nice too, being a 4-gang unit where most smaller receivers make do with 3-gang.

Now, I don't for a moment suggest that anyone pushes a 2225 that hard into 4 Ohm loudspeakers, not least because you'll heat things up alarmingly pretty fast, but it's good to know the receiver wont wimp-out on higher peek current demands into challenging loads.

 

[ConradH]

What frequency? It's toughest at 20 Hz because of power supply ripple. Also, you need to control the line voltage to factory spec. At 1 kHz on a good line day, surprisingly high numbers can be had.

 

[RobHolt]

What frequency? It's toughest at 20 Hz because of power supply ripple. Also, you need to control the line voltage to factory spec. At 1 kHz on a good line day, surprisingly high numbers can be had.

Hi Conrad,

I kHz test frequency. I'm in the UK and the 2225 is set to 240v, which is where my mains usually sits as I'm only about 80 yards from the power substation.
TBH I'm not too concerned with the 8 Ohm figure - its the nice substantial jump into 4 Ohms that surprised me.

The 2225 seems to have morphed pretty quickly into the 2230B, which looks identical right down to the schematic other than a couple of extra volts on the DC rail.

Is it true that the official Marantz RMS power rating is for rated power into the load for a period of 1 hour?
That's a tough endurance test and would likely explain why the published 8 & 4 Ohm rating is the same wattage. It's essential a safe current and temperature rating.

 

[ConradH]

I know at some point a preconditioning at some power level was required, which made the test a lot tougher. Don't know if that was an international thing, or just here, nor what Marantz did. That's why we have Marantz experts here!

 

[whoaru99]

Hi Conrad,

I kHz test frequency. I'm in the UK and the 2225 is set to 240v, which is where my mains usually sits as I'm only about 80 yards from the power substation.
TBH I'm not too concerned with the 8 Ohm figure - its the nice substantial jump into 4 Ohms that surprised me.

The 2225 seems to have morphed pretty quickly into the 2230B, which looks identical right down to the schematic other than a couple of extra volts on the DC rail.

Is it true that the official Marantz RMS power rating is for rated power into the load for a period of 1 hour?
That's a tough endurance test and would likely explain why the published 8 & 4 Ohm rating is the same wattage. It's essential a safe current and temperature rating.

Don't know if Marantz did things different, but normally it's 1/3 rated power for one hour using 1kHz sine wave for the old FTC preconditioning test. It's a very strenuous test because it is effectively akin to running the amp into heavy clipping if you were playing music.

 

[Abel Gaco]

I have a 2225L Marantz receiver and in my opinion, they have the most powerful 25w to 8ohms that I tested! I don't know how this receiver with only 25w is able to sound with this punch... I love my old marantz! ;-)

 

[catrafter]

I know at some point a preconditioning at some power level was required, which made the test a lot tougher. Don't know if that was an international thing, or just here, nor what Marantz did. That's why we have Marantz experts here!

FTC document from 1974. I wish I has a better copy.

 

[67dylan]

Was this w/the original internals or has it been updated w/new caps and such? I have a 2225 I picked up for $80 w/blown fuse. I love the sound from it and am going to do an update when I can find the time. Thanks for sharing the info, much appreciated mate.

 

[taineasy]

Bought a set of Mission Cyrus speakers recently rated at 4 ohms.
These really are a nominal 4 ohm load since they use two bass units running parallel and the minimum measured impedance is 3 Ohms in the mid-bass area. So likely to be amp fussy.

With that in mind I swapped out the sweet little Pioneer SA500A I'd been running successfully with some Quad ESL 57s and looked at my collection of vintage kit for something better suited to 4 Ohm drive.
Before doing so I selected my 2225 and thought I'd run some basic bench tests - power into 4 & 8 Ohms (both channels driven) and also response and tone plots.

Well, with a true RMS meter and scope attached I got 35wpc just before clipping into 8 Ohms, and a really very respectable 48w into 4 ohms. That's superb for a 25wpc rated receiver.

Quite the dark horse of the 22xx family, the little 2225.
Lovely sound, uncluttered internals so easy to service, runs cool, and good power delivery.
The FM tuner is nice too, being a 4-gang unit where most smaller receivers make do with 3-gang.

Now, I don't for a moment suggest that anyone pushes a 2225 that hard into 4 Ohm loudspeakers, not least because you'll heat things up alarmingly pretty fast, but it's good to know the receiver wont wimp-out on higher peek current demands into challenging loads.

The Marantz 2225 is a lovely rare receiver from the 22XX series. I am a bit surprized it is not discussed more often. This is a Direct-Coupled Dual Rail amplfier and not a cap coupled like most were. Secondly there were only two from the 22XX series that had the superb 4-gang tuner, the other being the 2270. This was a receiver for the person who did not need a ton power and enjoyed listing to FM broadscasts. It is a wonderful tuner and is far superior the 3-gang units found in all but the 2270, which was cap coupled. Production numbers on the 2225 was very small compared to the other models. Got mine from my father and would never part with it. Its a dandy!

 

[ocdecio]

The 2230 is cap coupled, not the 2245 or 2270.