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new to me magnestan SMGa

72.48.251.123

Posted on February 25, 2017 at 16:15:18
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014



hi all,

new to the forum and have been slowly trying to build up a home system.

i just picked up a pair of magnestan SMGa speakers (serial # 099704-1/2) after having researched on this forum and then bid on them at my local thrift shop. they appear to be a manageable project if in fact i need to spend time on them.

they have the beige muslin cover on them and i wanted to put together a plan of attack before i start messing with them. they /feel/ like they don't have any de-lamination of the coils after having felt them from the back through the fabric and they /appear/ to have very straight lines when looking through them.

i'm wondering if i can lean on some folks for advice on how to proceed. for instance, is first order of business to unscrew the sides, remove the staples and the muslin cover and inspect the coils and color of the glue?

can i play them with no cover if they look good? can i play them with a cheap ass sony STR K4800P receiver (!)?

right now i have a pair of advent heritage and a pair of baby advents that i bought cheap and had re-coned.

basically i thought to start testing them out a bit but also to start physically cleaning them up.

THANKS for any advice. i'm not super technical and not real audiophile but i do like my music.

and - er - that title should read "new to me magnepan"...!

 

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RE: new to me magnestan SMGa, posted on February 25, 2017 at 16:30:44
Green Lantern
Audiophile

Posts: 13576
Location: San Diego, Ca
Joined: November 12, 2002
Contributor
  Since:
June 17, 2003
congrats! the only way you'll truly know if they're delam'ed is if you fire em' up and hear buzzing or rattling.

Google your receiver to see if it hand handle a 4 ohm load, if so -you're all set. If you like what you hear don't worry about a new amp, Maggie (Magnepan) will let you know when it's time for a new one; although I'd suspect fairly early on ; )


 

RE: new to me magnestan SMGa, posted on February 25, 2017 at 19:54:48
Satie
Audiophile

Posts: 4222
Joined: July 6, 2002
1. see if they work without buzzes and rattles.

2. If they do, then hook up the legs and set them straight. Listen for a while and decide where you want to go on fabric and final results you would have in mind (e.g. adding subwoofers, or a supertweeter).

3. Later you should work on For best results, make new feet from stainless steel angle brackets from Home Depot, they just happen to have the same distance between the holes as maggies do. You use one in front and one in back for each leg and get a set of long enough screws and matching nuts to mount them, better if you can match the thread on the maggie screws. This should set them up vertically. But you need them to be raised substantially, so you need a box type stand to place them on so that the center of the panel is at ear height.You can start with a couple of cinder blocks per speaker.

If you are going to replace the fabric or you need to take it off to fix delam or broken wires, then order the socks from magnepan along with a wire repair kit if you need it, or buy the fabric from a craft store, thin spandex will do well.

 

RE: new to me magnestan SMGa, posted on February 26, 2017 at 06:28:09
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014



hey man,
thanks so much.

so adding a subwoofer or super tweeter seems like a long term issue for me. i guess you add one of these to get stronger highs or lows?

also, are there any links for this "crossover" issue? seemed like there was some modification involving a "crossover"?

also, i would probably fab something up out of steel or try to find something suitable if they need to be /raised/. do they need to be raised or can they just be tilted back? better to raise them i guess? can they be hung in the wall?! mid-panel seems like it would be a good two feet off the ground, no?

i removed the fabric since PG seemed to indicate that they damage the adhesive. i wonder if i can hand wash the fabric covers and reuse them?!

finally, they seem like they are in decent shape but could use some gluing down of wires. can i just use the contact cement PG recommends and glue down the loose wires as long as i am in there? doing the full 'banana peel' fix on these by cleaning off the substrate seems like it might be overkill for these.

THANKS

jon

 

RE: new to me magnestan SMGa, posted on February 26, 2017 at 06:29:08
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014



image 1 of 4

 

RE: new to me magnestan SMGa, posted on February 26, 2017 at 06:29:31
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014



2

 

RE: new to me magnestan SMGa, posted on February 26, 2017 at 06:30:03
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014



3

 

RE: new to me magnestan SMGa, posted on February 26, 2017 at 10:54:52
Satie
Audiophile

Posts: 4222
Joined: July 6, 2002
Obviously need to glue back into place those loose wires and those in the previous image.

That would not be a problem for testing the speakers to see if they work. .

 

RE: new to me magnestan SMGa, posted on February 26, 2017 at 11:40:11
Satie
Audiophile

Posts: 4222
Joined: July 6, 2002
The panels need to be vertical and centered at listening height to give you the kind of performance you want maggies for..tilting is only a partial solution to getting the speaker's aim right.

The crossover is simple and PG's suggested mods with his choice of caps (usually obligatto gold) is a good choice.

Getting a strong frame is something you need to decide whether it is within your capabilities in woodworking or not. Steel frames are more of a specialized skill. If you do build a new frame then you can use an extended bottom panel to get the right height.

Hanging them on the sidewalls in a perpendicular angle works ok, but does not give you enough clearance for the best performance. The maggies want to be far from the front wall (behind them) and work near the sidewalls only in particular arrangements.

The supertweeter and subwoofers extend the frequency range of the speaker upwards and downwards rather than increase output per se.

 

RE: new to me magnestan SMGa, posted on February 26, 2017 at 11:58:45
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014
thanks satie!

 

RE: new to me magnestan SMGa, posted on February 27, 2017 at 10:49:12
JBen
Audiophile

Posts: 2761
Location: South FL
Joined: May 18, 2008
Contributor
  Since:
July 26, 2010
Welcome to the forum, and to the planar's world!

Keeping in mind what you already saw from the rest of our gang, here are a few additional thoughts:
- That Sony receiver model may be fried if you force it to drive the Maggies past a certain volume point, unless it has good protection. For low-volume testing it may do.
- Of course, a good separate power amp could be the better option. The problem is finding a good used one for the right price. Still, patience and perseverance tend to help even if one is limiting the budget.
- Or, if you have a few limited bucks to invest, there are some oldie Denon receivers of the AVR-2xxx to AVR-5xxx series, that can -- increasingly with higher model# -- handle the challenge and even impress with good imaging. Every single one of these that I've tried could handle loads as low as 3 ohms, some lower. Typically made between 2004-2009, these same Denon AVR's have other hidden and potentially advantageous audio capabilities relative to some Maggies. (Please ask if interested in more detail.)


Interestingly, those pictures of yours unveiled something that I only suspected but never saw in pictures. They make obvious that my first-generation MMG's evolved DIRECTLY from your model. The wires' layout on the Mylar is exactly the same (except that they used quasi-ribbon instead of wire for the tweeter traces on the MMG's).

For this -- and other reasons -- one bit of good news is that your particular model may not be as bass-shy as many of the small Maggies, all other things being equal.

 

RE: new to me magnestan SMGa, posted on February 27, 2017 at 11:42:44
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014
THANKS JB!

working on building up some understanding and a system so all the help is appreciated. i'm really lacking on the technical knowledge so any "dumb monkey" explanations are always welcome. eventually if told enough time i tend to get it.

will be looking at receivers and amps in the coming month or so and will add denon to my list.

i am also trying to tackle which glue and method i can use on these. right now the wires are tacked down and held in place with those business card magnet backer deals.

so if i can find a good water based glue and if i can get the approval to just add some on top of the existing tacky 3M spray adhesive i think i could be good to go. i'm not real crazy about having to take up a lot of existing adhesive with acetone if i don't have to.

by the way, the 'socks' seem to have cleaned up nice so with luck i will reuse them.


THANKS

- jon

 

RE: new to me magnestan SMGa, posted on February 27, 2017 at 13:52:13
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014
hi jb,

any idea if you can help me read this as to whether my receiver can get hooked up to these maggies? i am assuming "NOT" since it is such a cheap piece but maybe i can learn something about how to read these specs and understand what i need to get??

Sony STR 4800P Specifications

AUDIO POWER SPECIFICATIONS

POWER OUTPUT AND TOTAL HARMONIC DISTORTION:
(Models of area code U only)

With 6 ohm loads, both channels driven, from 120 - 20,000 Hz;
rated 80 watts (STR-K5800P)/60 watts (STR-K4800P) per channel minimum RMS power, with no more than 0.7% total harmonic distortion from 250 milliwatts to rated output.

Amplifier section
Power Output

Models of area code U
(6 ohms 1 kHz, THD 10%)
STR-K4800P:
FRONT: 100 W/ch
CENTER W/ch
SURR: 100 W/ch

Models of area code CA
(6 ohms 1 kHz, THD 0.7%)
STR-K4800P:
FRONT: 100 W/ch
CENTER: 100 W/ch
SURR: 100 W/ch

(6 ohms 1 kHz, THD 10%)
STR-K4800P:
FRONT: 100 W/ch
CENTER: 100 W/ch
SURR: 100 W/ch

measured under the following conditions
Area code U, CA / Power requirements120 V AC, 60 Hz

Depending on the sound field settings and the source, there may be no sound output.

Inputs (Analog):
CD, MD/TAPE, VIDEO 1, 2, DVD / Sensitivity: 800 mV / Impedance: 50 kiloohms

Inputs (Digital):
DVD (Coaxial) / Sensitivity: -Impedance: 75 ohms
VIDEO 2 (Optical) / Sensitivity: -Impedance: -








 

RE: new to me magnestan SMGa, posted on February 27, 2017 at 14:38:29
Satie
Audiophile

Posts: 4222
Joined: July 6, 2002
The power rating is not promising for driving the SMG to good output. It is also likely to get damaged or power down when driving the maggies. Look for amps/receivers with power ratings into 4 ohms. As JBen indicated, older high end Denon AVRs and integrateds are built for the task and weigh accordingly, some well in excess of 50lb..

 

RE: new to me magnestan SMGa, posted on February 27, 2017 at 17:32:09
JBen
Audiophile

Posts: 2761
Location: South FL
Joined: May 18, 2008
Contributor
  Since:
July 26, 2010
LOL, I had already checked these very same specs earlier, before my previous posting to you.

It is too long a story to tell all right now but I am sure that you will get to understand it all in a short time. Just stay tuned to us maniacs around here and we'll make you a dizzy kind of Einstein. To really start you into some of the madness, perhaps Satie can tell more of it later. For now, let me just tell you about some of the "signs" to look for.

Notice how the 4800 is rated at 60 watts/channel RMS and later claimed to handle even 100 watts/channel, with the list of channels? (All, while at 6 ohms impedance, which is often -- though not always -- used to over-represent power ratings.)

Well, first, they mention "RMS" only in the first rating, for just two channels driven at the same time. Hey! That's fine. Among us ladies, RMS is called the REAL watts. Sony folks say "you drive this sucker on just 2 channels and we can deliver 60 real watts per channel...if the speakers stay at a nominal 6 ohms. (Most speakers are really 8 ohms, so less than 60 watts. Ironically, you "could" get more than 60 watts if your speakers are 4 ohms, like most Maggies...but...Sorry, not here. That's because of "hidden limitations".

See, they masterfully refrain from saying RMS (and definitely not "simultaneously") for the rest of the multi-channel sets, shown after the stereo figures. All they admit is to the large 10% distortion, more acceptable in low-end car stereos and in portables. This means that they are using a very liberal type of "watts" rating (there are several), clearly not RMS.

And as for the 100 watts each channel while played simultaneously, which is left to wishful thinking...HaHa! Omission caps the marketing subterfuge. (To be fair, few multi-channel devices deliver full rated RMS power continuously into all channels for any long period at the same time. But several do get there simultaneously for a short periods.)

So, at this point you start to smell the rats. Even without looking at the electrical power consumption ratings (an easy next step) it is clear that this unit has a very wimpy power supply. A very telling figure is the amps rating for electrical power. In addition, there's no mention of alternate impedances, much less of low ones. Take a look at the bottom of this capture from the Denon 2106 specs. It is not that they encourage the 2 ohms figure but mentioning it provides reassurances that it has enough current headroom. And more current is like having a larger pipe to supply more water when needed. (Ever seen those large caps inside amps? Those large cans are exactly like large water reservoirs. The larger the better to store current reserves.)



At most, Sony's receiver is rated at 1.4 amps max (165watts/115v). The wimpiest Denon I ever had was this AVR 2106 back in 2008, rated at 5.5A. And it still struggled with some of my...abuses. Imagine: MMG's tweeter directly (line-level at 2.6ohms), woofer segment at 4ohms, plus 3 surround speakers at 8 ohms ea. (And it is still driving speakers somewhere in the northeast:) These can now be found for about $100 on eBay at times. Far better yet is the AVR-3805, easily found for circa $200. This little tank of mine only died when someone accidentally poured a drink on it while playing. Those 7 amps on tap do sustain a huge soundstage when in Pure Direct stereo mode! Its overall SQ is commendable, I even keep a 4306 as pinch hitter so my separates can take a break..and it can even be a kick-asser.

But the Denons are not the only ones, just the ones I had a chance to abuse :) I am sure that you can find other candidates if you ask.

 

RE: new to me magnestan SMGa, posted on February 27, 2017 at 23:15:27
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014
thanks a bunch.

 

RE: new to me magnestan SMGa, posted on February 27, 2017 at 23:22:33
chertok22@gmail.com
Audiophile

Posts: 36
Location: texas
Joined: January 6, 2014
thanks man. looks like a deep dive. there's a reason i don't know this stiff'
going to chunk through this tomorrow.
THANKS for a nice head start...
- jon

 

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