Moog Matriarch Modifications

Any music gear discussions that don't fit into one of the other forums.

Moderators: Kent, luketeaford, Joe.

User avatar
Synthbuilder
Super Deluxe Wiggler
Posts: 3187
Joined: Tue Mar 24, 2009 9:12 am
Location: Cumbria, UK

Moog Matriarch Modifications

Post by Synthbuilder » Thu May 27, 2021 6:10 am

Warning: Long technical post

I've posted this on GS and AH but not here yet, so for those who have yet to see my modifications read on.

1. When you play between two notes with a large interval between them on the Moog Matriarch, you can hear a slight blip. It's a tiny glide added to every note change but it's very noticeable when the change in pitch is over an octave. So it was time to investigate.

I found the glide was due to the 150nF coupling capacitors that feed an inverted buffered version of the linear CV input into the exponential convertor on each oscillator. Remove these capacitors and the problem goes away. But then the linear CV inputs no longer work. So how to fix the slew and maintain the Linear FM inputs without excessive modification or track cuts to the PCB?

Below is the schematic, before and after the mod, of VCO1's exponential convertor. The other oscillators would need to be similarly modified.
Matriarch VCO mod 1.jpg
Be warned this is not a trivial modification as it requires, amongst other things, several 0603 surface mount resistors to be removed and/or replaced. Furthermore, four 1/8W through hole resistors need to be kludged onto the board and wired safely to the +10V supply.

As you can see I completely removed the 1.82M resistor that sets the standing current of the exponential convertor. I replaced the naughty 150nF coupling cap with a 910K resistor and made the output of the linear FM input amplifier a nominal -5.16V with an additional 91K resistor tied to +10V. This creates a similar standing current to that of the 1.82M resistor which was tied to -10V.

The feedback resistor of the linear FM invertor/buffer was changed to 47K while the input resistor was left at 100K. This gives roughly a -2.8V to -7.5V change at the output with the usual +/-5V modulation input signal which was sufficient for some nice, if restrained, FM tones.

The input is, of course, now DC coupled which is good for slower modulations and is completely symmetrical about desired VCO pitch. Any drifts due to input offsets in the inverting amplifier (U13) are relatively small compared to the nominal -5.16V output due to the low noise gain of the amplifier. I didn't see the need to change the TL074 (U13) over to anything better since the expo and CV summing op-amp (U5) is also a TL074.
Matriarch VCO mod 2.jpg
2. Each VCO has a LM393 dual comparator that creates both the pulse and square wave outputs. Each of the four LM393 devices is powered from 0V and +10V, and ideally its input pins should not go below -0.3V.

Pin 2 of the LM393 is the input pin that controls the pulse width of the pulse output and is directly connected to an op-amp output. It is 'protected' by a 1N4148 SOT23 surface mount diode (D4 on VCO1) which shunts the op-amp output to 0V when it goes below -0.6V. However, it is still possible for the voltage on pin 2 to go below -0.3V as the diode only clamps to -0.6V. When this happens the comparator's output will erroneously change state and becomes unstable and noisy. It may also shorten the life of the LM393. You can hear the instability by simply routing the attenuator output, which produces a variable voltage, into the PWM input and selecting pulse wave. Adjusting the attenuator produces some odd thumps and wheezes from the pulse wave output just after the pulse wave gets so thin it disappears. Ordinarily you would expect silence as the modulating input is increased still further.

The solution is to replace the silicon junction diodes with Schottky types, eg. BAT54L. These will conduct earlier and prevent the input to the comparators from going below -0.3V or so. The four diodes are D4, D8, D12, D16.


3. One other reported problem is that the pass band of the filter drops significantly when the cut-off frequency (Fc) is increased. This causes an obvious drop in volume when Fc is turned up or modulated upwards, say, with the ADSR. In many ladder designs this volume drop is caused by a non zero source impedance driving the base(s) of the lowest NPN pair. But the original Moog 904A module, from which the Matriarch's filter is derived, does not suffer from this because the bases are driven from low impedance outputs from an additional differential amplifier. So why the problem?

The Matriarch uses the same 904A ladder circuit including the discrete differential amplifier at the input. However, the emitters of the lower NPN pair of the Matriarch's ladder are not connected together like there are in the 904A but through two 10R resistors whose common point is then connected to the current sink via a 470R resistor. These two 10R emitter degenerative resistors act to reduce the gain of the whole ladder at high ladder currents. The purpose of this is unclear given the detrimental behaviour of the drop in pass band gain. However, maybe it is to tame excessive resonance at high Fc.

So to avoid the gain drop but still allow some degree of resonance taming, one can change the 10R resistors to 1R. The resistors are R200, R212, R359, R362.

The original 904A does not suffer from excessive resonance at higher Fc since the audio pathway from the top of the ladder output to feedback input is very short, ie. one emitter follower and one discrete long tail pair amplifier. Phase changes caused by additional poles in the feedback circuitry are likely to be small and thus self-oscillation is steady at all frequencies.

The Matriarch ladder filter's differential amplifier incorporates the same emitter followers as the 904A but then, instead of the long tail pair, a simple op-amp differential amplifier (with a large gain) is used. This is followed by a unity gain op-amp buffer that feeds the resonance pot which goes straight to the bottom of the ladder. The op-amp based differential amplifier has a small amount of high frequency roll off added with some capacitors which adds to the phase shifts. Removing these capacitors will allow the op-amp to run at full bandwidth and Q-enhancement is reduced.

To do this C124, C132, C188 and C89* on the middle main board can simply be removed and their spaces left empty.

* I think its C89 because it's difficult to tell as the legends are a little confused at that point. However, it's the only capacitor in a row of four components under quad op-amp U32.

I think the Matriarch uses CPU calibration to set the high pass filter null point, ie. the gain of the signal being subtracted from the buffered ladder output to create the high pass filter response must be controlled to produce the best HPF response. This is probably done at a high value of Fc and thus will be different now that the modification has changed the pass band gain at high Fc. To make the null point of the modified system have the same VCA gain as the stock circuit I needed to change R399 on the middle main board from 22K1 to 33K. R399 is the feedback resistor of the transimpedance amplifier on the output of the SSI2164 VCA chip.

4. High frequency loss in audio pathway between VCF output and main outputs.

Andy Simper of https://cytomic.com/ mentioned to me that he found the output of his Matriarch was significantly duller than it should be. I did some experiments and found that my Matriarch was also excessively low pass filtered too.

Here's Andy's results from his unit:

Image

We can see that compared to the raw sawtooth the eurorack output is somewhat low pass filtered cutting off the highs. This is significant, but now look at the main outputs which are even more filtered - some 15dB lower at 20kHz. Although most of us don't have ears good enough to hear up to 20kHz, a reduction of 15dB at 20kHz will have a significant impact lower down the audio band. Note the main output starts to attenuate the signal noticeably over 7kHz.

In addition I found that there was a moderate high frequency cut between the VCF output and the VCA input. You can test this out easily enough by simply connecting the VCF to the VCA with patch cords and comparing the sound when using just the internal normalised connections.

Dealing with the difference between the eurorack output and the main output first. The main output uses a dual SSI 2164 VCA circuit to allow the volume pot on the front panel to control the output level. The op-amp that takes the output of the VCA chip and converts it to a voltage has a considerable amount of HF cutting, over -10dB at 20kHz, and appears to start to roll off around 7kHz. This can be corrected by changing the two feedback capacitors, C348 and C355, around U39A and U39B, from 1n2 to 150pF. Both capacitors are C0G 0805 surface mount types. The VCA circuitry is on the right hand circuit board.

The eurorack output is also slightly filtered on the right hand output board and this can be alleviated by changing C15, C18, C19, and C24 from 470pF to 150pF. These are all C0G 0603 capacitors.

Some additional filtering can also be found in the dry/wet mixer circuit. This can be corrected by changing the feedback capacitors, C347 and C354, around the op-amp U40 from 270pF to 100pF. These are found on the right hand main board and both capacitors are C0G 0603.

The small loss of high frequencies between the VCF and VCA was tracked down to two circuit blocks, one on the middle main board and the other on the right hand main board.

On the middle board the two filter outputs go through additional circuitry that allows the user to switch between dual LP, HP/LP in series, and HP/LP in parallel. This circuit has a small amount of high frequency attenuation. To reduce this you can change C301 and C302 on the middle board (near U27) from 470pF to 47pF. Both capacitors are 0603 C0G.

On the right hand board it is the circuit around U6A and U6B. Here we can change C300, C301, C302, and C303 from 470pF to 47pF. All four capacitors are 0603 C0G.


All four modifications will take around a couple of hours to do as it takes a long time to take apart a Matriarch and put it back together again. Be very careful with the flexible multiway interconnects when you disconnect them as they are quite fragile. A little lever needs to be flipped up on each connector to allow the interconnect to come away.

Tony
You do not have the required permissions to view the files attached to this post.
Last edited by Joe. on Sat May 29, 2021 4:45 am, edited 1 time in total.
Reason: modified links and attachments for readability.

User avatar
kindredlost
5U skiff friendly
Posts: 5901
Joined: Wed Oct 28, 2009 1:45 pm
Location: FEMA Region 6

Re: Moog Matriarch Modifications

Post by kindredlost » Thu May 27, 2021 6:41 am

wow. I used to like the sound of the Matriarch until reading this. I suppose your warranty may not be good now Tony.

just kidding. Outstanding detective work my man!

User avatar
umma gumma
Ultra Wiggler
Posts: 999
Joined: Wed May 24, 2017 10:54 pm
Location: Canada

Re: Moog Matriarch Modifications

Post by umma gumma » Thu May 27, 2021 9:00 pm

I don't have a Matriarch, but I really enjoy reading about mods/improvements that can be made to gear like this

Thanks for making it available!

Did you finish modding your KT 320BBD yet? That looks like another great project

BlinkyLights
Super Deluxe Wiggler
Posts: 1324
Joined: Wed Feb 13, 2019 12:16 am

Re: Moog Matriarch Modifications

Post by BlinkyLights » Thu May 27, 2021 9:17 pm

Image links are broken

User avatar
EATyourGUITAR
has no life
Posts: 7750
Joined: Tue Aug 31, 2010 12:24 am
Location: Providence, RI, USA

Re: Moog Matriarch Modifications

Post by EATyourGUITAR » Thu May 27, 2021 9:21 pm

Removing the cap is removing a high pass filter. The low pass filter is in the negative feedback loop of the first opamp. When you AC couple negative feedback you are putting a high pass filter on the negative feedback which is effectively a low pass filter for that opamp gain stage. The best fix would be to change that cap to 47pf or simply remove it. You probably want to reinstall that cap that you removed and undo any other modification that you did. You can keep going modding the other negative feedback cap to 47pf. Or you can remove the feedback caps completely but you will have some snappy jumps in your CV with zero glide. The AC coupling cap is not a big problem. You would be better off putting a resistor in parallel. Maybe 1M like you already did. That will reduce the slope of the high pass filter. I didn't read your entire post so maybe there is more that I missed but I would start with the basics understanding the difference between a high pass vs a low pass filter.
WWW.EATYOURGUITAR.COM <---- MY DIY STUFF

User avatar
EATyourGUITAR
has no life
Posts: 7750
Joined: Tue Aug 31, 2010 12:24 am
Location: Providence, RI, USA

Re: Moog Matriarch Modifications

Post by EATyourGUITAR » Thu May 27, 2021 9:23 pm

BlinkyLights wrote:
Thu May 27, 2021 9:17 pm
Image links are broken
You can right click view image, that works. This is because of https and the browsers that have protection from cross site scripting attacks (XSS).
WWW.EATYOURGUITAR.COM <---- MY DIY STUFF

BlinkyLights
Super Deluxe Wiggler
Posts: 1324
Joined: Wed Feb 13, 2019 12:16 am

Re: Moog Matriarch Modifications

Post by BlinkyLights » Thu May 27, 2021 9:39 pm

EATyourGUITAR wrote:
Thu May 27, 2021 9:23 pm
BlinkyLights wrote:
Thu May 27, 2021 9:17 pm
Image links are broken
You can right click view image, that works. This is because of https and the browsers that have protection from cross site scripting attacks (XSS).
Thanks

User avatar
Synthbuilder
Super Deluxe Wiggler
Posts: 3187
Joined: Tue Mar 24, 2009 9:12 am
Location: Cumbria, UK

Re: Moog Matriarch Modifications

Post by Synthbuilder » Fri May 28, 2021 2:04 am

EATyourGUITAR wrote:
Thu May 27, 2021 9:21 pm
Removing the cap is removing a high pass filter...
The 150nF capacitor was intended as a AC coupling capacitor to inject a signal into the expo convertor. This allows for a sort of linear FM, and its value is large enough to let quite low frequencies through. However, the capacitor has unintended consequences. Because the left hand end of the capacitor in the schematic is connected to an op-amp output it is effectively sourced by a low impedance. For example, if there is no linear FM signal the capacitor is essentially grounded. The 150nF capacitor then creates a low pass filter in conjunction with the source impedance of the right hand transistor and pull down resistor for any signal coming through the right hand transistor. So it functions as both a HPF and a LPF depending on which direction the signal is coming from. The unwanted slew of the CV signal is caused by the LPF function.

The feedback capacitor on the op-amp (right hand side) is for stability purposes only and is of a low enough value for its roll off to be high enough not to cause any noticeable slewing of the pitch. I measured the slew rate of the signal at the output of this op-amp and it is plenty fast enough. The issue is entirely due to the 150nF capacitor.
Last edited by Synthbuilder on Fri May 28, 2021 7:38 am, edited 1 time in total.

User avatar
Synthbuilder
Super Deluxe Wiggler
Posts: 3187
Joined: Tue Mar 24, 2009 9:12 am
Location: Cumbria, UK

Re: Moog Matriarch Modifications

Post by Synthbuilder » Fri May 28, 2021 2:12 am

umma gumma wrote:
Thu May 27, 2021 9:00 pm
Did you finish modding your KT 320BBD yet?
I didn't do any more mods to that one as I decided it was easier to redesign the lot and start again. It's so fiddly to have to deal with all those weeny 0402 SMD resistors. So I came up with the Oakley DCR320 instead:
DCR320_front.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
medbot
Veteran Wiggler
Posts: 708
Joined: Mon Oct 28, 2013 2:44 am
Location: TX

Re: Moog Matriarch Modifications

Post by medbot » Fri May 28, 2021 11:04 am

EATyourGUITAR wrote:
Thu May 27, 2021 9:21 pm
I didn't read your entire post so maybe there is more that I missed but I would start with the basics understanding the difference between a high pass vs a low pass filter.
Imagine telling Tony Allgood that he needs to work on a basic understanding of simple filters. Fucking rofl.

Edit to add that these mods are great. You've got me wanting to open up my Grandmother to try your filter tweak.

User avatar
Antlerface
Wiggling with Experience
Posts: 268
Joined: Mon Apr 03, 2017 12:46 pm
Location: Chicago

Re: Moog Matriarch Modifications

Post by Antlerface » Fri May 28, 2021 11:18 am

medbot wrote:
Fri May 28, 2021 11:04 am
Imagine telling Tony Allgood that he needs to work on a basic understanding of simple filters. Fucking rofl.
Seriously, I’ve never “ignored” posts by a user before, but this cat is always tempting me to push that button haha
doomlove.

My Eurorack

User avatar
umma gumma
Ultra Wiggler
Posts: 999
Joined: Wed May 24, 2017 10:54 pm
Location: Canada

Re: Moog Matriarch Modifications

Post by umma gumma » Fri May 28, 2021 12:13 pm

Synthbuilder wrote:
Fri May 28, 2021 2:12 am
umma gumma wrote:
Thu May 27, 2021 9:00 pm
Did you finish modding your KT 320BBD yet?
I didn't do any more mods to that one as I decided it was easier to redesign the lot and start again. It's so fiddly to have to deal with all those weeny 0402 SMD resistors. So I came up with the Oakley DCR320 instead:

DCR320_front.jpg


Woah! Looks amazing

Currently building some of your dual VCA modules, but I may give that a shot afterwards

Ps the Grandmother doesn't need any of these Matriarch mods done, correct?

User avatar
EATyourGUITAR
has no life
Posts: 7750
Joined: Tue Aug 31, 2010 12:24 am
Location: Providence, RI, USA

Re: Moog Matriarch Modifications

Post by EATyourGUITAR » Fri May 28, 2021 12:28 pm

medbot wrote:
Fri May 28, 2021 11:04 am
EATyourGUITAR wrote:
Thu May 27, 2021 9:21 pm
I didn't read your entire post so maybe there is more that I missed but I would start with the basics understanding the difference between a high pass vs a low pass filter.
Imagine telling Tony Allgood that he needs to work on a basic understanding of simple filters. Fucking rofl.

Edit to add that these mods are great. You've got me wanting to open up my Grandmother to try your filter tweak.
First of all, I made a mistake. Mistakes happen. I willing to admit my mistake and take responsibility.

Second, it was a fair mistake to make. Normally AC coupling blocks DC. There are exceptions to the rule and this is one of them. Obviously I don't know as much about engineering as Tony All good. You can see that as evidenced by what happened here.

Third, I think it says a lot about Tony that he took the time to explain what I didn't understand. That was very nice of him to take the time to do that. Notice that what he did not do is make a post that has no valuable information. Unlike the people on this forum who only post negative rude condescending comments trying to push out and shut up anyone who is not an expert with a perfect record. This is why this place gets a bad rep for condescending pretentious elitist bullshit. Because of negative comments like this. If people want to mute me go ahead but if you just want to talk about muting me then why? Is it just to get attention? Anyone can PM me if they think I did something inappropriate on the forum. I am a nice guy and I would be happy to fix whatever I did to make this place better and more enjoyable.
WWW.EATYOURGUITAR.COM <---- MY DIY STUFF

User avatar
Synthbuilder
Super Deluxe Wiggler
Posts: 3187
Joined: Tue Mar 24, 2009 9:12 am
Location: Cumbria, UK

Re: Moog Matriarch Modifications

Post by Synthbuilder » Sat May 29, 2021 4:22 am

umma gumma wrote:
Fri May 28, 2021 12:13 pm
The Grandmother doesn't need any of these Matriarch mods done, correct?
I have had discussions with several people and we don't think it needs the loss of high frequency modifications. The Matriarch is stereo and uses a stereo VCA to control the overall volume of the synth, and it is the VCA circuitry that cuts the most high frequency. The GM has a mono output so probably has a standard passive volume control and should be fine.

The linear FM input mod which prevents the unwanted portamento, and the PWM clipping, I don't know about. You'd have to try it out and see. If you turn down glide to zero and play between top and bottom notes on the keyboard, and you can still hear a glide it may have the same problem. It's really obvious on a stock Matriarch when you use the arp and have the octave switch up to 3. You simply cannot turn the glide fully off.

The PWM clipping should be easy to test. Just put the VCO into pulse mode and modulate the PW with the LFO very slowly. If just after the sound thins it clicks horribly and perhaps even breaks into noise, then the diode replacement mod may be a worthwhile job to do.

The filter mod I'm also not sure about. I've listened to the GM demos on YT and I've not heard the obvious drop in gain you get on the Matriarch. However, this is easy enough to check. Put a lowish note sawtooth wave into the filter and turn up the cut-off with the resonance low. If once the sawtooth is nice and bright it then starts to drop in volume as you keep on turning up the cut-off, you may benefit from the change in the degenerative resistors. On the Matriarch it's really obvious when you modulate the filter with the ADSR.

Of course, the GM will have completely different component designators (R1 won't be the same R1 as on the Matriarch for example). I was tempted to buy a GM and take a look. There's one near me for sale for quite a reasonable price. But, too many projects, too little time, etc.

User avatar
Synthbuilder
Super Deluxe Wiggler
Posts: 3187
Joined: Tue Mar 24, 2009 9:12 am
Location: Cumbria, UK

Re: Moog Matriarch Modifications

Post by Synthbuilder » Sat May 29, 2021 4:34 am

EATyourGUITAR wrote:
Fri May 28, 2021 12:28 pm
Second, it was a fair mistake to make.
The stock circuitry is really unusual so it's no surprise you got confused. I couldn't make head nor tail of it when I first traced it either. It just didn't make sense. Basically, it's the equivalent of connecting two outputs together with a 150nF capacitor. The op-amp (U13A) will win because it has a lower output impedance and greater current capability. The only thing limiting the current injected onto the emitter of the right hand transistor is the reactance of the capacitor. Indeed, with high levels of FM input the BE junction clips hard. Probably doesn't do it much good.

User avatar
umma gumma
Ultra Wiggler
Posts: 999
Joined: Wed May 24, 2017 10:54 pm
Location: Canada

Re: Moog Matriarch Modifications

Post by umma gumma » Sun May 30, 2021 7:40 pm

Thanks for writing that up!

I just ran the tests, soundcloud clip below:

https://soundcloud.com/user-200002765/m ... other-test

part 1: Glide testing
part 2: PWM testing
part 3: Filter testing


1. The Glide seems ok, to my ears. I turned it up so you can hear the glide 2/3 way through, for comparison.

2. PWM has 2 quiet clicks at the end of each modulation

3. Filter test is harder to hear, but I did some rapid sweeps at the end where it's more noticeable. Although I thought it was a trait of the Moog filter to roll off the bass, because of the design? or is this something else

User avatar
Synthbuilder
Super Deluxe Wiggler
Posts: 3187
Joined: Tue Mar 24, 2009 9:12 am
Location: Cumbria, UK

Re: Moog Matriarch Modifications

Post by Synthbuilder » Mon May 31, 2021 4:05 am

umma gumma wrote:
Sun May 30, 2021 7:40 pm
I just ran the tests...
The PWM seems to have the same problem as the Matriarch. If you sweep the PWM manually you may hear that the clicks are bursts of white noise.

The glide is not so easy to hear as the notes played in the clip are of quite a low frequency. If you play again at higher notes, say two octaves up and maybe without any filter sweep, it may be more discernable. However, I now see that the GM has a linear FM input only on VCO2. This means if it did share the same VCO circuitry as the Matriarch the glide problem would probably only be heard with VCO2. So I tried to find some pictures online showing the PCB for the GM. Sadly, I found none, other than one YT video showing a somewhat irreverent (but entertaining) tear down. From what glimpses I got of the VCO circuitry, it does seem to me that the design of the VCO is different to the Matriarch. And given that no one has yet to complain about unwanted glides on the GM, I think the GM is free from the glide problem.

I think the filter seems fine, which agrees with what I've heard on the YT demos.
Although I thought it was a trait of the Moog filter to roll off the bass, because of the design?
The infamous Moog bass roll off is not always so well understood. It's not a bass roll off as such, but a lowering of the overall gain of the filter when resonance is turned up. If the filter cut off is set very high, say above the audio range, turning up the resonance will cut the volume of the whole audio band, not just the bass. To add to the confusion some Moog ladder filters (eg. Minimoog) actually affect the bass volume less at high resonance than they do for the higher frequencies of the input signal. That is, the resonance effect is not constant across the audio band but reduced at the lower end of the spectrum giving a lovely warm bass filter sweep.

The problem with the Matriarch's filter is that, even with resonance low, as the the filter cut off is turned up the overall volume of the filter drops. This happens with most ladder filters to a small extent, but with the Matriarch is quite significant.

User avatar
anselmi
Super Deluxe Wiggler
Posts: 4751
Joined: Mon Aug 24, 2009 8:08 pm
Location: Montevideo

Re: Moog Matriarch Modifications

Post by anselmi » Mon May 31, 2021 9:45 am

Synthbuilder wrote:
Thu May 27, 2021 6:10 am

Image
Who in this forum of decade-loud-synth-playing-old-farts can hear so high?
It is your dog posting?

Dymaxion
Common Wiggler
Posts: 64
Joined: Sun Oct 18, 2020 6:21 am

Re: Moog Matriarch Modifications

Post by Dymaxion » Mon May 31, 2021 10:34 am

If your hearing doesn't go up past 6k where the changes in that graph start, you should probably talk to a doctor, as that's a bit beyond the usual getting older. To be fair, the graph would be a lot easier to read if the traces where at least different colors.

User avatar
Synthbuilder
Super Deluxe Wiggler
Posts: 3187
Joined: Tue Mar 24, 2009 9:12 am
Location: Cumbria, UK

Re: Moog Matriarch Modifications

Post by Synthbuilder » Mon May 31, 2021 10:37 am

anselmi wrote:
Mon May 31, 2021 9:45 am
Who in this forum of decade-loud-synth-playing-old-farts can hear so high?
It is your dog posting?
In truth I hadn't noticed it until Andy Simper told me about it which was a month or so after I got my Matriarch. But although you may think you can't hear that high it is surprising the audible difference between the eurorack output and the main 1/4" outputs. Once I had heard that, I had to open mine up again and find out what the reason was. I bet if was 40 years younger I would have noticed it a lot sooner.

User avatar
anselmi
Super Deluxe Wiggler
Posts: 4751
Joined: Mon Aug 24, 2009 8:08 pm
Location: Montevideo

Re: Moog Matriarch Modifications

Post by anselmi » Mon May 31, 2021 11:24 am

Synthbuilder wrote:
Mon May 31, 2021 10:37 am
anselmi wrote:
Mon May 31, 2021 9:45 am
Who in this forum of decade-loud-synth-playing-old-farts can hear so high?
It is your dog posting?
In truth I hadn't noticed it until Andy Simper told me about it which was a month or so after I got my Matriarch. But although you may think you can't hear that high it is surprising the audible difference between the eurorack output and the main 1/4" outputs. Once I had heard that, I had to open mine up again and find out what the reason was. I bet if was 40 years younger I would have noticed it a lot sooner.
hahaha! I wasn't expecting an answer to my stupid post! sorry man it was just me trying to be funny, not trolling at all
great respect for your work and dedication

User avatar
anselmi
Super Deluxe Wiggler
Posts: 4751
Joined: Mon Aug 24, 2009 8:08 pm
Location: Montevideo

Re: Moog Matriarch Modifications

Post by anselmi » Mon May 31, 2021 11:38 am

Dymaxion wrote:
Mon May 31, 2021 10:34 am
If your hearing doesn't go up past 6k where the changes in that graph start, you should probably talk to a doctor, as that's a bit beyond the usual getting older. To be fair, the graph would be a lot easier to read if the traces where at least different colors.
just a joke, man
but after your post I revisited the plot and about 6K the difference seems to be 3db less around the -40 db area... mmm I don´t know if I could notice it by ear in a saw wave...maybe yes, but I´m not sure

towards the 10K region the difference seems to be enormous so I think that this would be easier to me, even with old ears...but I´m just guessing. Is there any audio file to check it?

Dymaxion
Common Wiggler
Posts: 64
Joined: Sun Oct 18, 2020 6:21 am

Re: Moog Matriarch Modifications

Post by Dymaxion » Mon May 31, 2021 11:56 am

Not meant super-seriously on my end either. And yeah, around 10k is where I'd expect it to become obvious to those of us without golden ears.

User avatar
umma gumma
Ultra Wiggler
Posts: 999
Joined: Wed May 24, 2017 10:54 pm
Location: Canada

Re: Moog Matriarch Modifications

Post by umma gumma » Mon May 31, 2021 6:21 pm

Synthbuilder: ah, I was only running VCO 1 in those tests

I can open the GM & get some PCB pics; surprised there are none on the 'net yet. I am happy with the sound of this thing, but in the interests of tweak & posterity ( tweakerity? ) I think it's good to investigate improvements.

Rex Coil 7
Super Deluxe Wiggler
Posts: 7515
Joined: Thu Nov 29, 2012 11:29 am
Location: Near the hole in the fence.

Re: Moog Matriarch Modifications

Post by Rex Coil 7 » Mon May 31, 2021 6:47 pm

umma gumma wrote:
Mon May 31, 2021 6:21 pm
Synthbuilder: ah, I was only running VCO 1 in those tests

I can open the GM & get some PCB pics; surprised there are none on the 'net yet. I am happy with the sound of this thing, but in the interests of tweak & posterity ( tweakerity? ) I think it's good to investigate improvements.
... postweekity .... ;)
Workin very hard to avoid becoming a statistic.
"Remember my spirit when that Slumerican flag waves.
From entrepreneurs, losers to users and renegades".

MODULAR SYNTH NORMALIZING PROJECT
NOTE: project stalled since Winter 2020

https://www.muffwiggler.com/forum/viewt ... highlight=

Post Reply

Return to “General Gear”