M vs MS

[fordtough1]

We talked in a previous thread about the differences sound wise between M amps and Ti amps, and I have heard the difference personally in twisted's suburban. To be honest I was blown away.

My question to those of you that have heard, what is the difference sound quality wise between the M and MS amps? Can you tell a big difference, or are they pretty equal when it comes to how they sound?

Also, which is the more reliable amp. If you had to choose between them is it a matter of preference, or is one really better built than the other?

Just satisfying my curiosity.

[AVICJR]

I believe it is a matter of personal preference. If you ask someone like Nico, he will more than likely prefer MS. I personally like the M series. Price wise there is no competition, M series are hands down cheaper. As far as reliability, I've had my M amps installed in my trunk in South E Texas on salt water for 13+ years and have had NO issues whatsoever. And, I've sent them into protection numerous times because of overheating. Let them sit for 15 minutes, and I'm good to go again.

[marko]

tough one, i have both m, mps and ms series amps and i choose to run ms, they just give amazing sq and rock solid build, just the 2200uf cap issue but that appies to all pg amps of that era...

funny because over here m series go for more that ms!! m50's are very popular

i don't know why but the mps2240 never sounded as good in the top end as an ms275

[eyesofra]

i dont own any of them but i know MS ( except for the MS275) is a close-to 100% dual mono design and has much robust power supply than M ...
there was a post by C in the past weeks on this.
surely this would make the MS a little higher end then the M wouldnt it....

[1moreamp]

Ok, Ok my ears are itching now TECH TALK TIME

A long time ago in a galaxy far far away, I worked at the only PG dealer in the SF bay area, and I loved it. You could not buy PG anywhere except us or Sacramento We had the product line locked up and business was very good.

We sold MS, MPS and MAC amps all day long to folks who could afford such high level products. < the key here is afford>

Then PG decided they wanted to sell more amps other then battleship competition grade amps. < their first products designed for market splash, and it worked very well PG was hot stuff, and special >

So a very smart fella figured out that PG needed to sell a NON competition oriented product line that did not run blow 2 ohms stereo. The products would be more favorable priced so the average car audio=phile person could and would buy PG products. VIOLA! The M series was born.

Now PG has a great sounding product, and it was very reliable for the most part, and with a 2 ohm limitation all they needed to do is cut-back the power supply from the battleship design used in the MS, MPS, and MAC amps to a more reasonable design that limited power below 2 ohms.
So here again VIOLA ! Less sink needed hence the M series sink and case design. A more civilized looking design to say the least.

NOW lets digress and pose a question at this point.

With the new M series limited power design, and new looks, and new lower price < remember all goals have been achieve here at this point>

Why do any of you think they changed the Amplifier channel design at all???

I explain here, They had a great product, They then trimmed it to gather market share of more reasonable and broader based clients < the average car audio buyer> A much larger market by the way. They now had the two big markets of car audio cinched with a complete product line that covered most every bodies needs.

Again here I digress and ask you why you think they altered the amplifier channel design ? A known fixed cost area of all there design work???????

Remember this line was based on costing less to garner market share, and with lower power the only scale back needed in the basic amp channel would be achieved by using lesser rated output devices, and they did use lesser output in all the M amps Except the M-50 and M-100. These used the same Toshiba devices the MS amps used.

Now please remember PG had a fairly unique design < yeah yeah the Triple Darlington design and all that> BUT they used high quality mylar caps where possible with only 4 little 33ufd caps inline with the audio signal, unlike many other that used dozens of electrolytic's through out the amp in between stage and such. PG was true Direct coupled < No caps> except those 4 33ufd 1 behind each RCA and 1 in the input of each channel. All the rest were Mylar and located in feedback loops just like the gains controls for noise free operation.

Now lets look at facts here, The M-25 and M-44 had smaller outputs, and the M-50 and M-100 had the same Toshiba outputs as the venerable MS, MPS, MAC line.
Oh and the M series would not have LEDs as the cases were closed so they leave out the LEDs and replace them with 2 signal diodes to achieve the exact same voltage drop in the circuit that the LEDs did.


NOW are we all on the same page here. I have listed everything I know to be technically different about these amps, and except for some different outputs I know of NO difference in the amp channels AT ALL.

So why does the amp sound better???? Any one ??? OK well they did redesign the case, the sink < both metal and not audio related> and they redesigned the what ?? any one ??? anyone ???

THE POWER SUPPLY IS DIFFERENT. it has extra noise coils that the MS amps don't have, and it has big current limit resistors that also exhibite noise reduction characteristics.

The power supply of ANY car amp has noise issues. Rectifier diodes and Mosfets are switching ON and OFF at very high frequency speeds and they make noise doing this, and this noise can find its way into the amp channel and the musical signal headed toward your ears. < by the way this is very high frequency noise and it attaches itself to the music and DOES affect how the high end sounds on ANY amp. You will never hear it on bottom end, But in the mids and highs is where you will hear it as a edgy harsh sound that aggravates long term listening. ( Even rodents and birds hate this sound, as we use this type of sound to shy away Pigeons and rats in public areas )

The M amps had extra components that limited power and killed noise while achieving power limitation they achieved cleaner more noise free power to the amp.

This is the only BIG difference in these amps. Other than this difference they used the exact same parts. IC's, Outputs, Drivers, caps, all the same.

As far as the better bass sound many of you report, (and I agree), well here again the power supply has a whole different set of operating characteristics, and there in lies a clue that it now handles power loading differently them the MS amps did. This is due to the extra components they added. These extra components will and did alter how power is delivered to the speaker load without changing the basic amp design in the channel. Also the M-100 has the same rail caps that a 2125 has in them so they store more power at the outputs then the same rated MS amp does. In fact the M-100 is bigger than a MS-275, and is smaller than the MS2125. In fact its built exactly in between these two MS models size wise.
If I want to upgrade from my Ms-275's but did not want to use MS-2125's I would buy M-100's to replace them with as the M-100 is twice built what a MS-275 is, and is usually much cheaper to buy than a MS-275.
In fact I am in the market for a set of M-100 right now to play with awhile, so don't be bidding against me please....

Now I am late getting to the shop and repackaging Fuzz's M-100 to return to him, BUT I will answer any and all questions you might have after this "soap box tech talk" I have done this morning.
So don't be shy, I will try to answer all questions or issues I may have incited this morning by opening Pandora's box of amp design and comparison on the fly

[thingy]

Spoken by a god Now for a funny Q - is it possible to switch the outputs on the M25 and M44 to the Toshiba's ?

[1moreamp]

Spoken by a god Now for a funny Q - is it possible to switch the outputs on the M25 and M44 to the Toshiba's ?

Sure , Why?

You can't get anymore power out by changing the outputs. the most you would do is gain durability in the output stage, and increased costs of course. But it can be easily done if you think its a SQ thing then i might understand the need. Some folks prefer the Toshiba sound to other outputs.

Side note: Toshiba stopped making these outputs in 2000, so there are fakes out there on the market, please be aware of this fact when considering buying Toshiba outputs for any PG amp. I have stocked parts from 10 years ago, so I feel good about my Toshiba's as they were made before they had fakes. But I only have so many, and after that I will have to be using ON semi outputs as they build a Toshiba killer device now that exceeds the original Toshiba device ratings and according to many has better SQ.

I would be more inclined to venture into upgrading to Sanken devices like the Xenon amps have in them. The Sanken transistors have a huge following worldwide for their dedication to LAPT <Linear Audio Power Transistor > designs and overall SQ in their products. Even PG went to them in the Xenon line. PPI had them since the PC series <i.e. the same output device that is>


C

[fordtough1]

I am amazed at your knowledge of these amps Cecil.

I had no idea that internally these were basically the same amps.

[1moreamp]

I am amazed at your knowledge of these amps Cecil.

Thank you !

[Pedi]

I am amazed at your knowledge of these amps Cecil.

Thank you !

And Cecil, now you might understand why I will ship all of my beloved PG-amps overseas for a "Cecil's touch", instead of letting a local dealer put their fat fingers into them??

[1moreamp]

Thank you Ivar.

[ydnap]

OK uncle see sill, why was one set called MPS (mobile professional series) and one just called MS (mobile series).

Am I teh l33t or was there another reason they knocked out the professional part?

[1moreamp]

The Professional series amps were rated for IASCA low ohm competition service, these were PGs real battleships as they were rated for 1 ohm service on a continuous basis and were sold for limited power rating SPL and SQ contests. The MPS 2500 was the biggest 100 watt amp most everybody had ever seen back then...

There were 100 watt cars and 500 watt cars and 1000 watt cars and unlimited cars. Everybody was trying to hit 150 DB's with 100 watts of power back then, or were battling in SQ contests within given power brackets.

I worked on a few cars back then, but it did not pay the bills and did not gain me any trophies for a lot of hard work tweaking amps and EQs and speakers trying for Max output or SQ.

The MPS amps here again are only different in the power supply. They have drastically reduced rail voltages so to prevent overheating while running super low ohms. AND the addition of a little transistor to the bias transistor mounted on the sink to improve high temp stability I believe.

You can't run low ohm loads with High Voltage rails inside amps.

Linear Power uses high voltage rails inside their TO-3 power amps, and thats why there is a load selection lugs inside them for 8 or 4 ohm loads. And they had such a selection of fan shrouds for all of their amps <They needed them for the excessive heat high voltage rails created inside these amps>
All the switch does is lower the power supply's output voltage so the amp runs reliably at higher current draw from the speaker loads.

Your amp you got from me has a switch inside I added < its not stock for that amp> it lets you run your amp in MPS mode or MS mode . I told you your amp was different from everybody else's out there, remember ???

That was one of my toys and tools you bought off of my bench, thats why it has such a super warranty, no one will be able to understand what I did to it, not even PG as its not stock to there making.

Its a one off, if your ever unhappy I will buy it back for what you paid for it


PS love your plate

[raffex]

1moreamp, thanks mate!

[1moreamp]

1moreamp, thanks mate!

Glad you found it helpful

[raffex]

anything you dont like about these amps.

[1moreamp]

Funny you should ask that " I hope this does not get me banned"

They ( M amps) have a motif of design that slows me down a bit. This is a personal opinion ONLY.
I will probably piss everybody off with this, But as I said its a personal observation about the physical design layout.

They remind me of a washing machine control panel

Now before this gets too far out of control, please allow me to explain myself...

The PG guy that did the layout for the package of this amp (IMO) had a unique package design idea concerning these M's. He wanted them to look different from any other amp, and so he got his wish by implementing this unique case design you see in all the M series amps.
My personal impression of its art deco design, is that it reminds me of a Kitchen Appliance in its motif.
The design was so unique that it was copied by offshore companies like Thump and some other brand we saw out of Australia last week. It was you that posted that pic was it not???

I was always told that "to be copied was the height of envy and prowess", and possibly respect. So PG got that and plenty more with this M series design.

Anyway, as I said when I look at these from a ART point of view, I just get this appliance feeling about it.
The MS, MPS, MAC amps were Industrial looking to me also , so its not a un-common feeling I get when I look at PG amps from this era.
They were all machines of a unique nature, just some seemed industrial and some seemed appliance in their overall looks.

Now would I do anything different inside?? well thats a personal question at best. But yes I would exercise my ideas on my M's if I had any left in my collection.
My posted M-44 should give you some clues, as to my ideas ( i.e. blue speaker wires instead of clear jacket as stock, and Plexi cover instead of the appliance sloped panel that is stock) My plexi was still sloped but it seemed invisible on the amp, and the amp displayed itself sorta like the MS,MPS, and MAC lines could do when they had their plexi's installed.

I am a techy kind of person so I like to be able to see inside my toys, just like my MS-275's that have had custom plexi on them so long I can't remember where I left the steal base plates for them

Are there any mods for the inside, well yes and no. I have seen a few places I would alter the assembly just a bit, but nothing electronics would change.
I feel that there are some hot spots inside this amp that need to be sinked for improved lifespan performance. I have never done the mods to any PG amp that I have worked on for my clients, as its not something you do to other peoples amps, especially without there knowing what the heck your doing.

You see I give my best efforts to restore this product to its original glory. that is time consuming enough as it is. But to alter anything takes more time just to implement any alteration you may decide to try.

Customizations are possible, but its a lengthy endeavor at best and if any of my work goes back to PG I want it to be as if they did the work and have no issues working behind me and my efforts.

I have not modded a amp in years even for myself. But I have tons of amps to chose from so I don't need to spend time building a monster. Plus being able to deliver original value to a item is a more dedicated pursuit IMO

Once you have altered a system design, you have created a "One OFF" as my British friends would say. It becomes a different animal, and because of that NO one wants to carry on the work of supporting the thing and its future needs of service. Mods can destroy a amps value, and when dealing with PG amps detracting from their collectible value is nothing to take lightly, and its not in the customers best interests ever to remove value from their investments. And PG has always been a investment for most of the PG'ers out there that I know of anyway.

Upgrading caps and burnt power resistors does no fall into my category of moding a amp. Improved components are not a mod, just a reliability increase and those are acceptable changes...


Andy, you are the exception to my rule, but you bought a personal amp of mine, and I told you up front what was up with it before your accepted it. So as I said you are the one exception to my rule.

[raffex]

thanks again. care to comment why some experience better "SQ" out of the M vs the ZX.

http://phoenixphorum.com/head-to-head-m ... t2291.html

Also (asking a lot here) can you possibly explain how older PG amps can be grouped, in terms of architecture/technology/design

eg.
MS + MPS -> M -> ZX (guessing here)
XS -> Tantrum ->
? -> Saphire ? -> ?

[Eric D]

I can’t believe anyone would hear a difference between them, as they use the same output circuit and in the case of a M50 or M100, the same output devices as well.

The MS, M, MPS, ZX, Ti, and even the ZPA all share the same audio circuits, aside from processing features, and slight changes in components. The primary differences between the models are power supplies, and power supply components. The MS and MPS amps seem to have the most robust power supply, with the ZPA after that, the ZX and Ti together after them, and the M series comes in last for power supply construction.

If someone does an A-B test of a M25, MS2250 (original), and a Ti600 for example, the following results are likely to occur…

With all amps level matched, it will be impossible to hear any difference between them at lower output levels. At these levels, all of them have no problem keeping up, as their power supplies are far from stressed.

At medium output levels, the bass response on the M25 will start to suffer. Its power supply will not provide enough current on larger transients, so the bass will begin to weaken, and possibly not even sound correct to the recording.

At high output levels, the Ti600 will drop off like the M25, but probably not by too large of a margin. It would depend on what voltage the two amps were matched at, and if that voltage is within the rated operating point of the Ti600. If outside this range, the Ti600 will really suffer, as it does not have enough headroom to make up for the MS2250’s more massive output voltage capability. If would not be fair to even compare the M25 at high output levels, as it is only a fraction of what its bigger brothers are for power output.

I am sure someone could make an argument that the ZPA sounds better than all the rest due to its overly large output array, which allows for each device to operate in a more linear region, far from saturation. Although this is possible in theory, my findings have been that the majority of PG’s designs are lacking in the power supply more so than in the output section, which would leave their outputs still in a very linear region far from saturation.

In my opinion, the only amp which really runs a risk of saturation is the MS275 (and its variations, MAC500, MPS2240). The power supply on the MS275 is really huge compared to the rest of it.

[smgreen20]

Enlighten me, what is the MAC500? Pics?

[marko]

Enlighten me, what is the MAC500? Pics?

mac500 is actually based on ms2125 ( ), mac200 is based on ms275. designed to deliver optimal power into higher loads, the opposite to the mps series.

[Eric D]

Looks like I made a typo. I meant MAC200, not MAC500.

[MW3]

Good discussion.

Eric D and onemoreamp know their stuff.

Here is couple of my thoughts.

- If you can hear the difference between ZX, Ti and M series amp you need to get a girlfriend.

- Eric D description of sound quality test is nearly right on. We did many of these in the past.

- Most circuit discussed here is right on target. Except M series was marketed and designed to "drive a nail" Granted the manual said stable to 2 ohms bridged, but basically it was stable until heatsink was saturated, and they rarely ever broke.

- Hardcore audiophile and ex-sound gurus at PG believe the best sounding (and biggest PITA amp) PG built was the ZPA series. I personally hated those amps, as they never worked right. Guess, who got the pissed off dealer/customer call when that $1000+ amp didn't work?

- MS2125 is best overall amp PG ever made IMHO. But very few people are willing to spend $800 USD for that amp nowadays.

[twisted]

- If you can hear the difference between ZX, Ti and M series amp you need to get a girlfriend.

although i may not have as much experience than alot of you guys here i have to disasgree with this statment,
only because not every vehicle has the same acoustics so some amps will have better sound or more headroom in certain vehicles than others.should'nt that be taken into account in a disscusion like this because after all vehicles are what we are using these amps in (mostly except for nico who will undoubtedly have the baddest home stereo on the planet)?

like the m25 and zx475ti in my suburban the m25 had more head room and a warmer sound than my ti amp did.

[1moreamp]

like the m25 and zx475ti in my suburban the m25 had more head room and a warmer sound than my ti amp did.

I might be able to explain the SQ difference you might be experiencing.

There is a adjustment inside each channel of all PG amps. Its the channel bias set point.
Now none of you guys run out and start fiddling with this adjustment as it requires a setup of equipment to do proper alignment of this set point.

I always check this calibration on every amp that hits my bench. this adjustment can cause the amp to sound differently. It can and does influence rated THD and distortion for each channel.
Improperly adjusted it can cause crossover notch distortion <screeching harsh sound in your high end> It can and will affect output power as the the entire output section of the triple Darlington stage needs this to be calibrated properly to achieve best performance and SQ, and to reach rated THD and power out.

Your AB comparison was done without this calibration being checked. AB SQ checking of amps that are off the shelf might need this calibration to be checked. And then the test done again. IMO

apples to apples I say....C