not to stir up trouble, but...

[MC]

Has anyone ever modified a Model D to include patch memory/recall?

LOL, the Source never sounded like a Minimoog. Nor did it had all the Minimoog features. But it had a nice S&H missed on the Minimoog.

I have minimoog, source, and voyager here.

Source is closer to a Minimoog than Voyager. It gets that high end sheen that is missing from the Voyager and the basses have more low end.

[Rob Smith]

I agree with MC the Source is closest thing I've heard compared to a Model D. My friend Neil used one in a Pink Floyd tribute band for years and it pulled off the mini stuff with ease. The touch membrane was its main weakness though

[torinkrell]

In the last year I have noticed that you can often get new membrane control panels for vintage synths like the Source and Prophet 600 online. I am also amazed by all the other new parts being made for vintage synths like voice chips for Juno 106s and sliders for old ARPs.

Although I mentioned it earlier I believe its important to emphasize that Minimoog Model Ds appear to vary in their sound more than all the other synths I have experience with. My two Pro Ones have different warmup times and knob feel however they sound very close to each other in sound. Both of my Rev3x Prophet 5s also sound very close. With the 3 Minimoog Model Ds I've owned over the years however each had different sound characteristics that are more significant than just a slightly different parameter range or calibration of their knobs. The Minimoog Model Ds variability is probably due to several factors including its discrete parts as apposed to the curtis chip based Sequential gear, design changes - esp in the filter & oscillator as well as the natural variability caused by aging.
Has anyone else here compared Minimoog Model Ds?

[unfiltered37]

No, but I will say that my model D sounds different almost every time I've played it. I have gotten sounds out of it that I will probably never get again. At one point I had had it sound exactly like my clavinet, so much so that my buddy, a fellow clav owner thought it was indeed a clavinet. I think different temperatures as well as warm up times and settings all play a part, but that is what I love about it.

[Kevin Lightner]

Has anyone else here compared Minimoog Model Ds?

Exhaustively.

There's many changes everywhere.

One of the largest changes is that earlier Minis drove their filters harder than later ones.
But there's just sooo many changes between early and later ones.
Power supply, wood type, wood thickness, panel type (metal, vinyl, vinyl with metal backing), wheel types, rectifier board parts and values, addition of small circuit changes (VCO high end tracking improvement via delay lines added), gold plated connections on later ones, countersunk nuts on later mod wheel brackets, all sealed pots on early ones, AC line voltage switches on later ones, fuse values, different value resistors on the tuning pots (3.3K vs 5.1K),DPDT type rocker switches with doubled-up contacts for reliability while earlier ones used SPDT switches, etc, etc, ... I could go on for quite some time.

I've documented many of these changes between new and old ones.
But I don't always know exactly when or what serial number these changes were made at the factory.
Online info is sometimes wrong too as a person might have an earlier Mini that was later updated and they didn't know.
Many changes are easier to spot when you have several Minis available to compare and few people except synth techs might have 4 or 5 Minis available at once for comparison.

Sometimes I even have to ask my clients which changes they'd prefer because they'll deliver an early Mini for restoration, but then ask for any later factory changes made.
But they might not know that very late Minis had softer A-440 signals or that the filter gain structure was changed or whatever.
Not every change made is considered an improvement by everyone.
As another example, some players can't stand the later ribbed mod and pitch wheels.
They got used to rolling their palms on their smooth, earlier wheels.
That might hurt if tried on later wheels.

Anyway, there were lots of changes made through the years.
Most were fairly minor, but everything adds up to sometimes make one Mini sound different than another.

[MC]

The touch membrane was its main weakness though

I owned mine since 1985 and had zero issues with the touch membrane.

The secret is to use your fingertips on the membrane switches and not your fingernails.

[MC]

Has anyone else here compared Minimoog Model Ds?

Not as exhaustively as Kevin, but a major change was the transistors used in the ladder filter.

In the early models they matched all five pairs of transistors in the ladder filter, then later ones matched only top and bottom pairs. A study of schematics revealed this. It is not known when this change was made.

I own one of the early RA Moog ones and the two other RA minis I played sounded exactly like mine. All three had different oscillator boards.

Later minis sounded drastically different and the sound wasn't consistent from unit to unit. The resonant color of the filter was different. In the 1970s Rick Wakeman owned four of them because each one sounded different.

The minimoog filter is a 24dB/oct filter, aka as a four pole filter in frequency domain theory (EE 485 material). If the poles are not equidistant then the 24dB/oct rolloff varies from its textbook optimal, thus changing the timbre. Four of the five transistor pairs in the ladder filter comprise each filter pole. Because the middle three transistor pairs in the ladder filter were not matched, the filter poles varied from unit to unit which accounts for the sound differences.

It is also the primary reason why Voyager owners complain that it doesn't sound like their model D. The Voyager matches all five transistor pairs and the resonant color is really close to my RA. But owners of later minimoogs will hear a difference.

[sunny pedaal]

i've got 3 mini's: 2 2000 and a little, 1 3000 and a little.
soundwise the differences aren't spectacular.
mostly they different in layout/ knobsform, and the sn2000 something in some way seem a bit more easy to play: they tune better and are more stable over time then the sn3000 one.
( all three have been well serviced )
of one sn2000 however the keyscontacts in the high region are a bit more worn out then in the other sn2000 and the sn3000 one.
all have smooth white pitchwheels.
overall one of the 2000 ones ( 2100) i like most, soundwise not much difference can be found ( they all have a tiny bit of character of their own , not very much ,and none is exceptionally better or worse )
compared to the minimoog-voyager they all sound better, tighter in the fast attacks, fuller in the bass and more pronounced in the high. no exception. also the external in sounds better ( less thinned )
the voyager beats them all in possibilities of sounddesign though

[unfiltered37]

In the 1970s Rick Wakeman owned four of them because each one sounded different. .

More likely because he had different patches setup for each for live stuff. I doubt the difference between minimoogs of varying models is more significant than different individual units. My model D can sound extremely dynamic timbre wise on different days with the same settings. I don't know if that's dried capacitors or what, but I like it, keeps it fresh, though some days are better than others.

[Kevin Lightner]

Has anyone else here compared Minimoog Model Ds?

Not as exhaustively as Kevin, but a major change was the transistors used in the ladder filter.

In the early models they matched all five pairs of transistors in the ladder filter, then later ones matched only top and bottom pairs. A study of schematics revealed this. It is not known when this change was made.

It's not known when this change was made because this change was NEVER made.
From production beginning to production end, they all used matched transistors in their filters.
Every one.

Moog matched and placed a spot of paint only on selected or matched transistors.
In every Mini I've ever encountered (400+), all transistors in the filter sections have paint spots.
Whether early RA, Musonics or very late ones every transistor in the VCF section had paint spots, including the ladder transistors.

Also, I will cite Norlin/Moog's Factory Service Bulletin addendum number 804C, dated 9/81.

"Please make the following corrections and additions to your manual before proceeding with a repair:
(many items cut here for brevity)

"On page 9-9
Change note 3 to read:
Q26 and Q28 are matched to +/-3mV, Vbe at 20 mA IC."

"Add to note 5:
transistor pairs: Q5 & Q7, etc Vbe matched to +/-4mV at IC = 20 A."

Those 4 trannies are in the filter.

[thealien666]

..."Add to note 5:
transistor pairs: Q5 & Q7, etc Vbe matched to +/-4mV at IC = 20 A." ...

I didn't know the Mini's filter could handle so much power ???

[sunny pedaal]

that's why they're soo fat

[MC]

It's not known when this change was made because this change was NEVER made.
From production beginning to production end, they all used matched transistors in their filters.
Every one.

Moog matched and placed a spot of paint only on selected or matched transistors.
In every Mini I've ever encountered (400+), all transistors in the filter sections have paint spots.
Whether early RA, Musonics or very late ones every transistor in the VCF section had paint spots, including the ladder transistors.

Also, I will cite Norlin/Moog's Factory Service Bulletin addendum number 804C, dated 9/81.

"Please make the following corrections and additions to your manual before proceeding with a repair:
(many items cut here for brevity)

"On page 9-9
Change note 3 to read:
Q26 and Q28 are matched to +/-3mV, Vbe at 20 mA IC."

"Add to note 5:
transistor pairs: Q5 & Q7, etc Vbe matched to +/-4mV at IC = 20 A."

Those 4 trannies are in the filter.

The FSB 804C refers not to the transistor pairs but to the differential recovery amp (Q5/Q7) and the control Qs at the bottom of the ladder (Q28/Q30). Neither of these have any impact of the spacing of the poles.

The transistor pairs are Q2/Q3, Q10/Q11, Q19/Q20, Q23/Q24, and Q29/Q30. Matched pairs are designated on the schematic with an "M" enclosed with a circle, and only Q29/Q30 are marked as matched.

However I can't dispute having the hood open on 400+ minimoogs and seeing marked pairs in the ladder circuit. And schematics have been known to be inaccurate.

[thealien666]

All the trannies in the filter on mine are matched, indicated by a blue dot in the ladder and a purple dot in the buffer amp.

http://www.flickr.com/photos/47250566@N ... hotostream

[Kevin Lightner]

Yeah, that's 20ma, not 20A.

I do have a Moog ladder filter here I made with 250 watt TO-3 style transistors tho.
Sounds great. Never matched any trannys for it tho.
Just an experiment that I really didn't think would work as well as it did.
But who needs a filter that can drive a speaker directly?