p.s. - I will have no responsibility for the outcome if anyone tries this, this is a untried concept.

And it makes very little sense from the viewpoint of risk versus reward. You’re first and last statements sums up everything ... “Most will agree...” and “this is a untried concept.“

I’m not sure, at all, that most would agree... in the first place. Action is personal taste. And preference can be argued... what cannot be argued however is the last statement. That is true!

Better solution: if you want a MODX8 with Yamaha’s Balanced Hammer action... get a MONTAGE8. It’s a better option all around. Low risk, big reward!

You’ll be much better off (happier), you will not void your warranty, nor will you completely ruin your synthesizer. Yep, it is about twice the price and weight, but rather than just taking that money and setting it on fire (doing that suggested modification) which could leave you without a working synthesizer, why not sell your MODX8 and save up to get the MONTAGE?
Risk: No one will be interested in purchasing your hacked (up) GHS action synth...
Reward: You get the deluxe interface, Balanced Hammer action w/Aftertouch, and a great new instrument with a full warranty.
AddEd reward — another musician gets to enjoy a fully working MODX8!

Just my 2 cents ... I think “most“ would agree
But thanks for your ideas, though!

Extra Credit: ... if you only knew how much R&D goes into these (I’m sure the folks responsible will get a kick out of your post). No single action will please every player, to be sure... but the GH action found in the MODX8 is among the best selling 88 key action on this planet — it’s in the top 2! (I say that on the outside chance there is one I don’t know about). 🙂

I think the appeal of the MO series has always been how much you get of Motif for such a discount. So value certainly has a bearing on sales. Sales may not necessarily be an endorsement of the keybed. That said - it's difficult to make any kind of determinations based off of number of sales (who knows, maybe everyone is buying MODX strictly for its keyed).

That aside - I can say I agree that the MO series graded hammer keybed in past generations - this one included - has always felt, to me, sluggish/heavy/less responsive (than the balanced). Even a key with seemingly the same "weight" on a GHS vs. the balanced key of the same "weight" feels better to me.

I really don't think that making all the keys the same weight on GHS would, at least for me, drastically root out what I don't like about the feel of GHS. Because even after you trim the weights - there's going to be one key that doesn't get trimmed. And that key I still don't like the feel of. And now they all feel that same way.

There's more to it than just the mass of this metal structure that goes into the feel of the keybed. I think if you did do this experiment - you'd be invested into the change. It'd be hard to go back without buying new parts. That'd go a long way to convincing yourself that something is better. But I'd strongly advise against doing this unless you can find someone else that's done it - and really really prefer how that keybed feels. Or unless you have the money to burn to experiment and just buy another keyboard if the experiment fails.

..

Bad Mister - the cost of keboards such as the montage have become ridiculously delusional, I never thought I would see the day when you choose to either buy a nice second hand small car or a keyboard ! - as for the MODX8 keybed I have seen reoccuring comments about it's 'quality' (or lack of) - ironically as well reoccuring comments favor the MOTIF series 88 key BHE keybeds, so it's not the old 'if you wanted a better MODX8 keybed you would have had to pay more' arguement.
And as for my MODX8 keybed modification suggestion, yes it is radical, and a lot of TLC would need to be practiced in carrying it out, and yes, it's a one-way street, and yes, (formally) it isn't advisable - but your 'option' of buying a montage instead is, as I said, (financially) delusional for too many - I can SAFELY say most if not all are just-fed-up with the ridiculous exponential increases in music gear prices all around, and sometimes 'out there' options are floated simply out of sheer frustration.

I really don't think that making all the keys the same weight on GHS would, at least for me, drastically root out what I don't like about the feel of GHS. Because even after you trim the weights - there's going to be one key that doesn't get trimmed. And that key I still don't like the feel of. And now they all feel that same way.

I think the only way this can possibly work even on a conceptual basis is if you were to say, "gee, I kinda like the feel of this action in its top octave, I wish the whole board could feel like that."

A possible gotcha I could see is if the samples are programmed to sound "right" based on the lower keys being heavier to play, and so if those keys are made no heavier than the top keys, you may hit higher velocities sooner than intended and that could impact the sonic playability of the piano. A simple velocity curve adjustment could not correct for that, you'd need to alter the velocity response for each key individually, i.e. if the MODX8's normal velocity coding is assuming that each key is weighted differently and that is no longer be the case. Maybe it matters, maybe not so much, but it is a possibility to be aware of.

On the flip side of that, the exact same patches are in the Montage 8, where they are in fact deigned to be played by a balanced action! So there are two possibilities: One is that they customized the piano sample/velocity mapping for a graded action when they decided to come out with the MODX8, and so altering the weights of the keys could really throw a monkey wrench into how they programmed the sound. The other possibility is that that the samples/velocity mapping were brought over to the MODX unchanged from the Montage, i.e. with no specific mapping for the MODX8 separate from the other 5 models (the MODX8 having the only graded action among any of the Montage or MODX variants). In which case, if the sounds were originally velocity mapped for a balanced action in the first place, and they never coded a separate MODX8 implementation to alter the response for a graded action, they might actually play better if the MODX8 were made balanced!

It would be an interesting experiment, but it could be a costly one. If all GHS actions are interchangeable, it might be worth buying an old GHS board (they go back at least to the P85), maybe even one sold extra cheap because of (non action related) issues, and chop THAT one, and swap it into the MODX8 whole, leaving the original MODX8 action intact and unaltered so you could reverse the surgical procedure if it doesn't work or you want to sell it. Even before making the swap, you might be able to use your chopped up P35 or whatever as a controller to trigger the MODX over MIDI and get a sense of how it would sound triggering the MODX sounds even before opening up your MODX8. I'd probably rather chop up a used board I got for $300-$400 rather than risk the MODX8 and possibly make it unusable/unsellable.

I think the MODX8 offers great value for money. I have used it for live gigs for about a year. Though in hindsight I am very disappointed in it's keyboard action. I own several 88 and 73 keyboards. Among them a Yamaha CP4, still one of my favorites, with probably a bit more expensive keyboard. I would not consider to tweak the MODX keyboard. Just sell it, as Bad Mister suggests. I will (but not to buy a Montage 😉 )

I have both a Yamaha S90ES (with BHE) and a MODX8 (GHS); for me, I WAY prefer the S90ES playability
I agree that you should not modify the rods... there's more that goes into the action than this, there is a greater probability of disappointment, it's a one-way trip.
I could buy a Montage but don't want to... it's too heavy and less portable, like the S90ES. Portability was a huge factor for me in getting the MODX8.
**So, here is my related question*** Can I SWAP out the keybeds, to make a MODX with BHE and and S90ES with GHS? Are they mostly plug and play, so to speak? If I could make a lightweight MODX with the BHE, my life would be complete. If Yamaha made an MODX8 + BHE, I'd buy it today. And thoughts/ideas? Thanks!!

Can I SWAP out the keybeds, to make a MODX with BHE and and S90ES with GHS? Are they mostly plug and play, so to speak? If I could make a lightweight MODX with the BHE, my life would be complete.

I don't know, but even IF the connectors were identical and even IF the physical dimensions lined up such that it would fit, I'm not sure it would be the lightweight board you're after because it's also possible that the action itself is substantially heavier than the one its replacing. Which then also brings up the variable about whether the existing plastic chassis could properly support the additional weight of the heavier keyset. Unless you've got money to burn, I wouldn't risk it.

Mechanically I'm not sure they would be drop-in compatible. Because one is heavier I would have to think the mounting is different. Maybe a different size/shape to fit in the chassis. I'm just not sure. The GHD-EBUS boards stay with the keys themselves and detach as an assembly. I don't have the MODX manual - so this assumes nothing has changed in the general construction for MODX vs. previous keyboards.

Electrically it could be done - but possibly not without some hacking. I'm not sure the cables are drop-in. When I take a look at MOXF vs S90ES - the cables are not drop-in.

I know what I would do to make this work. It wouldn't allow a swap where both synths end up with each other's keys. I'd rob the I2C GPIO board from the donor (S90ES, for example) and then connect the keyboard at the output of this GPIO board's I2C signals. I would disconnect the MOXF's I2C GPIO parts by depoping the series resistors. And certainly power/gnd the donor I2C board. I'd leave the original I2C GPIO board in MOXF so the connectors (ribbon) to the rest of the system are there. I2C is easy to splice in since it's only 2 wire.

There are other hacking things that may need to happen. The S90ES has some keyboard to GPIO connections the MOXF doesn't use. This is fairly simple to patch up. But it does require some expertise to recognize what to do.

This isn't simple plug-and-play on the electrical side.

Notice I kept saying "MOXF" - again, I'm using the reference information I have. Things may be completely different with MODX. But based off of the predecessor - there are several electrical considerations which make this not plug-and-play. And I see no reason for an even newer generation to present less differences. Therefore, I think it's fair to say it's highly probable that although it could be done (electrically) - it would take skill and work to accomplish. And likely require donating a board so you could not "swap" (both ways).

The easiest thing to figure out is if they are mechanically compatible. If they aren't - then it may not be worth if you end up with too much of a hack job to fit the S90ES keys inside a MODX. I really don't know.

But beyond that - I would not advise doing this even if mechanically compatible unless you are OK with any warranty voiding (MODX) and also have the skills to deal with those "nudge" items you would have to do on the electrical side.

There are keyboard techs out there who have demonstrated facility at restoring old keyboards and also modify those keyboards with new features - or create "Frankenstein" keyboards. These are the kind of techs who could do a job like this. If you're not somewhere close as accomplished as them - you may want to call them up and ask them what it would take to do what you want. That's more advisable than tackling the job yourself if you have any doubts. I'm not naming any specifically because I'm not here to advertise. But you can do your own research. I've seen more than one place that advertises this kind of thing - so you can find your own path if that's the route you go.

I actually think the best solution is to take a MODX6 and MIDI connect an 88 key controller of your choice. But I do understand the pitfalls of that (more gear to carry, lack of button integration straight on the 88 key controller, etc).

Here's what someone did to their Korg Krome when they wanted to use it as a module with some other set of keys, I suppose you could do something like this with a MODX too...

Oh my gosh, someone chopped a Korg Krome? Hilarious!

I use a Modx6 along with a Roland A33 controller and assign the midi channels accordingly; like having two independent keyboards.
Even though the Roland isn't full-weighted it feels really good to me and weighs almost nothing.

Can't beat the capability, versatility and price of the Modx, this combination is best live rig I've ever owned....

is this you????

>>youtube-modifying MODX<<

If the keys are too light they would also spring back slower too no?

I'm very interested in this tho, as you can see I've posted on the other yamaha forum that i might be selling mine if I cant find another solution.

>>my thread<<

I actually have a p-35 in my cupboard too!

If you dont mind, what nationality are you because I am English and I would love to hire you to service mine if you do that sort of thing and it works.

Rather than shaving bits off the high hammers to make them the same as the lower hammers, a more sensible approach would seem to be to buy a bunch of hammers of the type used for the high keys (i.e. as replacement parts), and install them in the rest of the keys. This would have the benefit of presumably being more accurate in making the keys identical than you could get them modifying them by hand, and has the even bigger benefit of being entirely reversible if you don't like the result or want to return it to stock to sell the board. You can find the various hammers for sale at https://syntaur.com/keyboard.php?keyboard=2208 and you can see that the lightest, highest keys use the hammer marked #4. Or maybe you could ask a Yamaha service center to get the parts for you. Either way, it may not be cheap. Syntaur charges $6.95 per hammer, and if you have to replace 3/4 of the hammers, that's 66 of them (though I don't know the exact breakdown of how many keys have which hammers, so that's just an estimate)... you'd be talking about putting $400-$500 into it. And again, it will make all the keys feel like the top octave currently does. If you like that feel, this could conceivably be beneficial. If you don't even like the way the top octave feels, there's not much point to spending all that money in an attempt to make the whole board feel like that. Though if you prefer the feel of the section of keys with the #3 hammer (second section down from the top), you could choose to make all the keys that way, or whichever of the 4 weights you liked best.

Based on another Syntaur page, it is the #4 hammer that is used throughout in order to created the balanced version that's in the CP73. The keys and hammers for the CP73 are the same part numbers as those for the top keys of the MODX8. Though that doesn't mean it will necessarily feel identical, as there could be other differences that could conceivably alter the feel between the two boards, for example how the keyboard mechanism is mounted in the chassis, or possibly just the feel imparted from being in a metal chassis rather than a plastic one. Programming can also makes a big difference. I really disliked the feel of the CP73/YC73 action... but there was a software update that allowed you to better customize the velocity response, and it made a world of difference. Which also makes me think that, rather than just basing whether or not to consider this based on how you feel about playing the top octaves of the MODX8, to do a more thorough prediction of what you might be able to expect out of making all your keys like those top keys (or any other of the 4 available weights), you could play those keys on the MODX8, octave shift them to trigger notes in other regions, play with the velocity settings, and see more precisely how you might be able to get those keys to feel if used over different ranges, with the velocity adjustments that are available. If you're going to put hundreds of dollars into this experiment, you might as well do your reconnaissance and gather as much intel in advance as you can!