View Full Version : Marantz 250M


onemug
04-19-2012, 02:38 AM
I may be getting a pristeen Marantz 7t preamp and I've been thinking about what ss Marantz amp I would like to pair with it.

Seems like a 15 or 16 would be among the usual suspects. Having the 18 and 19 receiver, I have a rough idea what they may sound like but the 250M is quite a looker and has my interest also. I have no idea what it sounds like compared to the 15/16.

Any comments/experience about a 7t/250m combo? Synergy?

The speaker I use is an easy 8 ohm load and fairly efficient. The 18 with its 40 watts does all I need and I'm just interested in the 3 I mentioned.

jstang
04-19-2012, 07:49 AM
I think it's more a question of the making sure the units are in tip top condition and then having a proper set of speakers for the system. The 250m and 7t should be very nice together.

But it's just an estimate on my part never having a 250m. I have heard the 7t with 510m, nice....close combo.

Jk

bktheking
04-19-2012, 10:05 AM
To bad you didn't live closer, I'd lend you my 250 to try out.

ConradH
04-19-2012, 10:24 AM
I don't know the difference between the 250m and 250. I've got a 250. It's an ok sounding amp but I'd offer a caution. IMO, it's an amp running on the edge of disaster in terms of voltage and semiconductor ratings. High line voltage will probably fry these. I got mine cheap because of shorted outputs and rebuilt it. I remember it (haven't looked at the circuit lately) as having way too many capacitors and being overly complex for the performance it achieves. Dirty bias pots or an open in the Vbe multiplier wires will fry it instantly. Wonder how I know that? A lot has been learned about amplifier design since the '70s. If I were buying one, I'd want it carefully checked out and maybe recapped. They do look very good in a system and once mine was fixed up it remained reliable.

ChrisMarantz
04-19-2012, 10:38 AM
I have used my 7T with every amp I own, including models 15, 16B, 32, 140, 170DC, the the amp sections of models 1200, 1030 and 1060.

While each of these amps have their own individual sound the 7T simply adds to the quality of the sound in each case.

I have been listening to a 1030 which I rebuilt recently. I have not been a big fan of this little amp and I was surprised to hear the 1030 so differently when I hooked up the 7T to it.

The 7T seems to be such a great pre-amp that it works very well in almost all applications.

onemug
04-19-2012, 10:50 AM
Thanks for the responces.

Gut and intellect are converging toward the 16. I forgot there is a 16 and a 16b. More power in the B. Did it lose any sweetness?

bktheking
04-19-2012, 11:32 AM
This is from another site, cure to the 250.

1) Degenrate the diff amp's emitters with 200-390 ohm resistors.
2) Add in Collector to base capacitors on the pair of VAS transistors (Q507, Q508).
3) Insert base stoppers between the VAS and the first driver transistors (22 ohm) and also base stoppers in the 4 output transistor base leads (2.2-3.9 ohm).

What the hell is he talking about? Add some resistors and it's cured?

PB_Audio
04-19-2012, 11:35 AM
I can tell you, in its power range, the Model 250 is a fantastic amp.
It's rated at 125 WATTS/Ch-RMS, but puts out closer to 180W/Ch-RMS when in top condition. The 250 has excellent build quality, and the design is free of some of the quirks of many of the earlier models.
For Marantz, the Model 250 and Model 500 were the high-point for Marantz solid state amp developement in their respective power range with regard to performance and reliability.
Don't get me wrong... I'm a fan of the Model 18 and 19 receivers, so I like the Model 15 and 16 amps, in principle; but, IMHO, I would recommend the Model 250 as the better value, cosmetically, as well as from a performance and reliability point of view, hands down.
Others may recommend the more recent Models DC170 and DC300. They are very good, but are not a good cosmetic match. You would need the DC300 to equal the performance of the 250; but then, given its greater rarity, you would pay more, and likely experience greater difficulty finding major replacement parts , if needed.
Check out this link:
http://www.classic-audio.com/marantz/0250.html

PB_Audio
04-19-2012, 11:38 AM
This is from another site, cure to the 250.

1) Degenrate the diff amp's emitters with 200-390 ohm resistors.
2) Add in Collector to base capacitors on the pair of VAS transistors (Q507, Q508).
3) Insert base stoppers between the VAS and the first driver transistors (22 ohm) and also base stoppers in the 4 output transistor base leads (2.2-3.9 ohm).

What the hell is he talking about? Add some resistors and it's cured?

Interesting...
Where did you find this info?
Personally... I love a good mod.:yes:

ChrisMarantz
04-19-2012, 06:49 PM
Thanks for the responces.

Gut and intellect are converging toward the 16. I forgot there is a 16 and a 16b. More power in the B. Did it lose any sweetness?

The have had a 16 and I still have a 16B. I would say that they sound very much alike. I prefer the 16B for its additional power. Most 16B's will require some refurbishment at this point.

They are fairly easy to work on however they usually need a lot of component checking to catch all of the out of spec parts. In the last 16B I rebuilt about 50% of the resistors were out of spec.

Here's a few pictures to get you started

bktheking
04-19-2012, 08:12 PM
Interesting...
Where did you find this info?
Personally... I love a good mod.:yes:

http://www.diyaudio.com/forums/solid-state/148403-marantz-250m-repair-5.html

PB_Audio
04-19-2012, 11:41 PM
Cool, thanks bk. I'll have to check it out. I recently picked up a 250 in need of a full refurb... perfect for experimentation. The faceplate got bent in shipping, so it's going to become a workhorse.
Jay

bktheking
04-19-2012, 11:56 PM
Ah crap, I saw a nos faceplate on ebay a couple of months ago, he wanted crazy money for it. Try straightening it.

PB_Audio
04-20-2012, 12:26 AM
Ah crap, I saw a nos faceplate on ebay a couple of months ago, he wanted crazy money for it. Try straightening it.

Yah, they really don't straighten very well, unless it's just a gentle, minor bend. I straightened a Model 510M faceplate that wasn't my best work. Three corners were heavily bent. (I used to restore sportscars. Steel is far easier to straighten than aluminum.) Oddly, I had a 510 faceplate (no meters, and not a match. Go figure.)
Actually, I have several other mint 250 amps... it really is one of my favorites.
I bought it to refurb anyway; so, now that it's banged up, all mods are fair game. :D

onemug
04-20-2012, 02:21 PM
You mentioned the 16B needing refurb and not the 16. The B would be newer though. Is it because they run it harder to get the 100 watts than the 80 of the basic 16 or are there other reasons?

I'm sure either could use some tune up. Also, would you say the 16 is a little sweeter sounding than it's successor?

Thanks.


The have had a 16 and I still have a 16B. I would say that they sound very much alike. I prefer the 16B for its additional power. Most 16B's will require some refurbishment at this point.

They are fairly easy to work on however they usually need a lot of component checking to catch all of the out of spec parts. In the last 16B I rebuilt about 50% of the resistors were out of spec.

Here's a few pictures to get you started

ChrisMarantz
04-20-2012, 03:14 PM
You mentioned the 16B needing refurb and not the 16. The B would be newer though. Is it because they run it harder to get the 100 watts than the 80 of the basic 16 or are there other reasons?

I'm sure either could use some tune up. Also, would you say the 16 is a little sweeter sounding than it's successor?

Thanks.

I never ran the 16 and the 16B side by side, however I think they sound very much alike.

I didn't mean to imply that a 16 would not need some refurbishment, I'm fairly sure it would need about the same amount of work as a 16B

onemug
04-20-2012, 06:33 PM
I never ran the 16 and the 16B side by side, however I think they sound very much alike.

I didn't mean to imply that a 16 would not need some refurbishment, I'm fairly sure it would need about the same amount of work as a 16B

Thanks.

I was looking at your collection. Where does the 15 amp and 7t preamp rank (individually, not as a pair)?

ChrisMarantz
04-20-2012, 07:09 PM
Thanks.

I was looking at your collection. Where does the 15 amp and 7t preamp rank (individually, not as a pair)?

I really like the model 15 amplifier, mine is a very early version. The sound from a 15 is sometimes referred to as "grainy" due to it being an early solid state design. I'm not really sure what "grainy" means. I enjoy the sound I hear from my 15.

The only down side with a 15 is the age of the unit. I don't use it as much as I might want to because it is all original. With some refurbishment work I would probably use it more often.

The 7T is a fantastic preamp which I find enhances the sound of every amp I have use it with. My 7T's are all original and would benefit from some refurbishment.

I am torn on these early models when it comes to rebuilding them. Keeping them original is not practical if they are going to be used daily and not fair to the equipment if original means they don't sound as they should.

Rebuilding them is a greater effort than rebuilding later models and with my limited time I guess I just leave them as they are and use them less than I would like to.

I really enjoy all of my models and I don't play favorites except for my 2226B which I have had since 1977. My shop set up has been a 16B with a 33 preamp for the past year and I don't see changing it right now.

Sooooo many models and sooooo little time :D

onemug
04-20-2012, 07:42 PM
ChrisMarantz, Thanks again. I can tell you really love your equipment.