MCS amp. info. needed

[Racingh11]

I'm just pointing out that the common opinion of anything from Japan is high quality is wrong, and even if a unit has excellent specs, it can still sound like garbage. And I was comparing it to a unit that people tend to dismiss because they are more concerned about bragging on forums or the local "bench racing" as it is called in the automotive world. "No mine is faster, look how big the cam specs are!" = "No mine sounds better, look how low the distortion spec is!" Yet when put to the test, one is a mismatch which does not perform, and one sounds like a walmart stereo.

 

[SVI2004A]

That opinion burns out bullshit meters, even the ones used in Congress.

 

[Racingh11]

That opinion burns out bullshit meters, even the ones used in Congress.

lol, those meters are made in China...

 

[SVI2004A]

The old school ones weren’t

 

[Hifirob2]

The MCS 2270 is no slouch... and would knock off some of the NECs off their pedestal

So I wouldn’t write off Matsushita...

I have the 2250 amp from that series - and I do like the sound. But the phono preamp is just ok, and the matching tuner and cassette deck are barely acceptable, performance-wise. The later MCS 2255 and 2256 rack systems were even worse. Take the covers off the tuners and cassette decks from these series, and try to find more than a few bucks worth of parts. The most valuable part just may be the little incandescent bulb that backlights the LCD display. I like the EQs that came with these systems - Technics never made a bad EQ. I just got a Technics SU-Z950 integrated amp, and it works - so I can't complain - but it will never earn a place in one of my main systems. I'm going to attempt to power a subwoofer with the SU-Z950. If it works, great. If it bakes itself to death (I'll be using a cooling fan), I wouldn't care. Just another $10 amp. Those wonderful SVI chips deserve a better built "host" amp, IMHO.

Generally, I love Technics better stuff. My 676 cassette deck is insanely overbuilt, and performs wonderfully. My main turntables are all made by Technics, and nothing will replace them. My SA-1010 isn't going anywhere - but it seldom leaves my closet. I have a few ST-S505 tuners that perform excellent - but their sound quality is thin compared to others, so after a few hours of listening, fatigue sets in.

My reason for my comments are because MCS switched sourcing from Matsushita and NEC depending on the year (for their top systems), and it was probably due to the higher margins on the Matsushita pieces. I have assembled MCS systems from most every year, and the NEC-made ones are built like tanks, and are more reliable. The NECs all have a sound that is very accurate, defined, and clear. It's just my preference - I prefer to listen to the Matsushita amps through headphones only.

As good as the 2270 amp was, assemble the entire matching system from that year (1985). Now gather together the entire top system from the 1986 1/2 model year. That was the last system sourced from NEC. It had 125 wpc, came with a fine tuner, cassette deck, EQ, and a killer CD player. It even came with a system remote control. Compare these two stacks side by side, and really listen to them. Take each piece apart and take note of the parts quality - then decide. The SVI chip based 2270 is nice, but the rest of the system falls short. For 1987, 88, and 89, MCS went back to Matsushita - probably because NEC no longer produced anything that would meet Penney's price point. It was all downhill from there...

 

[Racingh11]

Thanks Hifirob2, that's interesting. Your knowledge and research is appreciated. The 3840 is a 82-83 model, it's far better that the stuff you find at your local big-box store, but does not have the feel of the Arvin stuff from the same time and few years earlier. It's really more of an 80s era style box than the Arvin line, so push-button is going to feel different, no doubt. And pretty much all mass produced brands became lighter, flimsy, plastic versions of themselves as time went on. The arvin toggle switches, potentiometers, push-button switches, all have a really solid action and sound to them. I think the problem with the 3840 is likely in the tone controls. I haven't seen a schematic, but it is a night and day difference in sound on the two. I was really amazed at the sound and details I was hearing on records and things in songs I hadn't noticed before(great tweeters). Then I plugged the setup into the 3840 and it it was all gone, and not only that, but what was there no longer sounded real. Out of balance or phase issue maybe. I hooked up an EQ to the monitor circuit and made it a little better, but it still is all wrong. I will say it gets better as the volume is turned up, sounds decent when you want to pound some tunes. Good shop/garage stereo for some one...

 

[Bob]

if you still need a transformer then find the supply voltages necessary for the power supply.

then if you open it up you can note all the power supply components for their values and
work forwards and backwards a bit.

for example, if the large power supply caps are rated at say, 60v, then its safe to assume max
PS is ceilinged at 60v. depending on the number of such caps (paired) then its a dual voltage PS.

if there are voltage regulators, look for the zeners that base the regulators. you'll have a
minimum by inspecting the zeners. the actual VR regulates above the zeners. USUALLY.

the transformer will have some clues, same color wires (pairs) usually (but not always) indicate
dual supply voltages. some units also feed multiple sets of dual voltages for std ICs and/or Opamps.

 

[SVI2004A]

I have the 2250 amp from that series - and I do like the sound. But the phono preamp is just ok, and the matching tuner and cassette deck are barely acceptable, performance-wise. The later MCS 2255 and 2256 rack systems were even worse. Take the covers off the tuners and cassette decks from these series, and try to find more than a few bucks worth of parts. The most valuable part just may be the little incandescent bulb that backlights the LCD display. I like the EQs that came with these systems - Technics never made a bad EQ. I just got a Technics SU-Z950 integrated amp, and it works - so I can't complain - but it will never earn a place in one of my main systems. I'm going to attempt to power a subwoofer with the SU-Z950. If it works, great. If it bakes itself to death (I'll be using a cooling fan), I wouldn't care. Just another $10 amp. Those wonderful SVI chips deserve a better built "host" amp, IMHO.

Generally, I love Technics better stuff. My 676 cassette deck is insanely overbuilt, and performs wonderfully. My main turntables are all made by Technics, and nothing will replace them. My SA-1010 isn't going anywhere - but it seldom leaves my closet. I have a few ST-S505 tuners that perform excellent - but their sound quality is thin compared to others, so after a few hours of listening, fatigue sets in.

My reason for my comments are because MCS switched sourcing from Matsushita and NEC depending on the year (for their top systems), and it was probably due to the higher margins on the Matsushita pieces. I have assembled MCS systems from most every year, and the NEC-made ones are built like tanks, and are more reliable. The NECs all have a sound that is very accurate, defined, and clear. It's just my preference - I prefer to listen to the Matsushita amps through headphones only.

As good as the 2270 amp was, assemble the entire matching system from that year (1985). Now gather together the entire top system from the 1986 1/2 model year. That was the last system sourced from NEC. It had 125 wpc, came with a fine tuner, cassette deck, EQ, and a killer CD player. It even came with a system remote control. Compare these two stacks side by side, and really listen to them. Take each piece apart and take note of the parts quality - then decide. The SVI chip based 2270 is nice, but the rest of the system falls short. For 1987, 88, and 89, MCS went back to Matsushita - probably because NEC no longer produced anything that would meet Penney's price point. It was all downhill from there...

The 2250 / 2270 systems were direct fabrications from the no frills Z400 / Z600 systems, - they were the IMO the better offerings of Matsushita- was surprised to see the Z600 rebadged, as Matsushita put a fair bit into the R&D of its power amp. And more surprised to see the MCS line get extra features like the power display led array..

You are right saying that a better host amp makes a difference, as the V4X (Technics) was on the same power ic with better power supply and front end with MM and MC phono capability

The NEC line you’re talking of is a different level - 125/ch vs the 70/ch.. though the 70/ch would acquit itself adequately - the ST-Z400 tuner was again the no frills option
The EQ and cassette deck would have been base models... and right with 87,88 on - systems just didn’t have what the 84/85 sets did in sound (well in Matsushita lineup anyway)

Would be interesting to do the comparo... but here in Australia I am afaik the only one in the state with a MCS amp... would be interesting to hear the later setup on the 2270 amp... which doesn’t look like a lot with the lid off... would have liked to see more adequate resivoir caps - but the SVI keeps a remarkable sound with difficult speakers...

I’d guess dry joints to be the issue for any reliability issues with the Matsushita amps...

I am curious to see the CD player you talk of... the 80s had some cool units

 

[Hifirob2]

The 2270 amp has a lot of potential, I think. The MCS 2255 amp (from 1987) is fun, in that it must have been based on some 60 (or so) watt Matsushita amp. The MCS is 100 wpc, and has a pair of 8000uF caps on the main board - plus they added an extra board (mounted just to the right of the transformer) with a pair of 4700uF caps. That bumps it up to 12700uF per channel for a 100 wpc amp. That's pretty decent. The following year gave us the MCS 2256, and it just has one pair of 10000uF caps for it's 100 wpc. That's ok. But....this SU-Z950 is supposed to be 110 wpc (is that right?), yet the main caps are 66 volt, 8000uF. That seems like not enough, IMO.

The CD player I mentioned was the MCS 6807. It was based on the NEC CD-500, and sounds better than it should. All the NEC sourced MCS CD players were very nice sounding - all using a nice Burr Brown DAC. Aside from the MCS 6801, the Technics sourced MCS CD Players were pretty dry and clinical sounding. Not a lot of those have survived all these years.

MCS did get a rebadged Technics EQ (MCS 2295E) near the end of the 80s that had the spectrum analyzer display. Seven bands, and no mic input, but pretty nice - considering. The Technics model number was SH-8044. Most of the EQs were versions of the SH-8017 or SH-8038. The MCS 2295 system (I believe) came with an amp the had a remote control, cooling fan, and pre-out, main-in jacks. I would like to find one of those and see what it's like. I already have the remote for it - just no other pieces outside of the EQ.

 

[SVI2004A]

Haven’t had a Z950 in front of me... I know it’s based on SVI2105, yet the info I have claims min 8 ohm... the SU-V97 also is SVI2105 and is 4 ohm rated... (may have impedance/tap select switch)

It would be cool to see more of the MCS lineup, as it never surfaced in Australia -

Interesting is that some of these models 2250 / 2270 systems for example also surfaces under the Curtis Mathes branding.

 

[Hifirob2]

Curtis Mathes used the same playbook for audio in the 80s as Penney's did. They used NEC and Technics, starting with the NEC line in 1981-82. They got some of the better NEC models, but they sold so few, they are hard to come by. My EQ for my MCS 2250 is the correct model, but it wears the Curtis Mathes name, so it's champagne colored face stands out against the other silver faces.

All of their receivers were from Technics from 1982 through to about 1986. When MCS stopped selling receivers around 1986 - sourced from NEC, Curtis Mathes offered a few of their models up until the end of the 80s.

 

[Racingh11]

Anyone know what the idle current should be on the 3840? This one is 25mV and 15mV across both .22ohm segments of output resistors on each channel. I'm thinking it should be more like 5mV putting the current at about 11mA or maybe less yet. Does anyone have a service manual or schematic for this they would be willing to share?