Amek M2500 thread

[jensenmann]

It could work if the dimensions are right. Definitely measure them before ordering.

 

[Spaceyjb]

Great!
I finally got back to GroupDIY and found this thread. I have bought M2500a for about 7 years ago and was quite lost, becouse of lack of any inforamtion. So i am really happy to find this thread.
I love the desk. We fully recapped it and rebuild PSU. We used different fuses than original has as + rail burned quite often and we found out we cannot find originals ones.
I use the desk everyday since - mostly for recording. I have tried to mix on it, which turned ok, but there are some problems there, as my desk was unfortunately modified to bring 72 channels to the mixbuss. As i do not have much time for finishing repair of the desk I postponed work on this.
I think i probably ask some question about that later, but for now i'd like to ask about main input module channel PCB. My plan was to get rid of the modification and put it into original state. For that i do need new main PCB boards. Have you made them new and where?
Next: i thought to turn some of the preamps to trasformer ones. It seems it is easy "swap the board" option. I did not find anybody having PCB board layout of those.
If anybody needs i have full original schematics and schematics for my modification (if someone is interested). I will post more about my desk later.
Thanks
Jan

 

[jensenmann]

Hi Jan, welcome aboard!

I doubt that anyone has a complete layout of the M2500A main PCB. You´d better try to bring the modules you have back to original state.

The transformer preamp uses a different gain pot than the transformerless preamp which means the boards cannot be interchanged without replacing the pots. I made a layout for the transformerless preamp card because a friend needed these for his desk. But I don´t have a layout for the transformer preamp as my desk is fully fitted with these anyway. I´m not sure if it´d even make sense to do a 1:1 layout as Sowter, who made the original transformers for these boards, changed owner and seems to not make as many custom jobs as they used to. Add ROHS on top of that and it´s pretty unlikely that these trannies will be available at all. From a technical POV they are 1k:5k 1:2,25 mic input transformers (PRO AUDIO TRANSFORMERS ARCHIVE look for 4057). They could be replaced with other brands, e.g. Lundahl LL1528. But as the circuit in general is nothing special I don´t see any advantage in swapping transformerless to transformer preamp cards.

 

[Spaceyjb]

Hi Jan, welcome aboard!

I doubt that anyone has a complete layout of the M2500A main PCB. You´d better try to bring the modules you have back to original state.

Hi Jensenmann.
Thanks a million for opening this thread and for your great tips ragrding buss amp and bypass capacitors. I will definitelly try them out.
Regarding bringing my desk to original state: Unfortunatelly it seems the modification was too aggresive - including backplane and adding summing amps - so i am quite scared to do it, using old PCBs. Lots of significant czech albums were recorded and mixed on this desk, so it should be well thought of. As soon as i get to documentation i will post the schematics of the modification. Maybe someone will find it interesting.
Thanks for explaining tranny pres. I thought it could be interesting to have that option, but if there is no significant sonical advantage and it requires gain pot change - i won’t do it. As i said i am scared to solder to main PCBs more than necessary, as they feel quite sensitive.
Jan

 

[jensenmann]

You are right, the PCBs are "home-etched style" and very sensitive to mechanical stress. Any work on the PCB needs to be done very careful in order to not lift or break traces.

Keep us updated with the modifications. It´d be very interesting, at least for me, what the previous owner changed.

 

[glbaudio]

I've made with Eagle the re-draw of the Schematics and PCBs of M2000A modules, submodules and power supply, as I'm an M2000/2500 owner.
I've also made a substitution for the Hamlin reed relay.

 

[ilfungo]

Hi glbaudio
you have redraw all the PCBs?

 

[glbaudio]

Hi glbaudio
you have redraw all the PCBs?

Mostly. Input channel, All the sub-boards in various versions (eq A and C, VCA Allison and DBX, ...), all rails of power supply. And the reed relays adapter.
Still missing the other modules (Aux module, C/R, and Studio monitor), no time to do it!
I have all the scans, but to search a problem, the redraw is really useful.

 

[MidnightArrakis]

I've made with Eagle the re-draw of the Schematics and PCBs of M2000A modules, submodules and power supply, as I'm an M2000/2500 owner.
I've also made a substitution for the Hamlin reed relay.

Send me all of your EAGLE files, BOM's and the dimensions of the PCB's and I will take a look at them and see if I can help you guys out here!!! Include any information that details modifications and upgrades that either has already been implemented or that you wish to have implemented. Then, I can include those wishes into new layouts. Attached are some PDF files of my previous PCB designs for your review.

In addition, I can also offer you assistance with any mechanical designs as well. Just sayin'.....

/

 

[58Glammer]

Hi, great thread!
Could someone post pics of the different sections of the channelstrip? I just saw pics of the complete board, where you can´t see that much details
Also I would be interested how you all proceeded with your boards. These posts are from 2021
I have some PM01 modules in a frame I just recently recapped. But as I read through this thread, I saw it´s recommended to exchange the tantal through electrolytics. Superb!

 

[jensenmann]

IIRC the tantals in the EQ module are across the rails. It´s a very good idea to replace them with electrolytics and increase their value at least x10.

 

[glbaudio]

Hi, great thread!
Could someone post pics of the different sections of the channelstrip? I just saw pics of the complete board, where you can´t see that much details
Also I would be interested how you all proceeded with your boards. These posts are from 2021
I have some PM01 modules in a frame I just recently recapped. But as I read through this thread, I saw it´s recommended to exchange the tantal through electrolytics. Superb!

next time i will go in my town (where I have the console) I will do it!

 

[jessequin]

Hello all. I need to recap some sections of my M2500 but in order to get at the relevant parts I need a nut spinner with a very thin wall as a normal one won't fit. Has anyone else encountered this issue and if so what do you do about it?! Thanks

 

[MidnightArrakis]

Nobody here in this thread seems to have any interest with responding back to anybody!!! I posted a reply 2 years ago exactly from TODAY with no response and GLBaudio posted a response 8-months ago also with no response. Maybe this thread is dead!!!

/

 

[S.Samuelsson]

I need a nut spinner with a very thin wall as a normal one won't fit. Has anyone else encountered this issue and if so what do you do about it?!

Not a case specific solution, but the folks who have the access to a lathe just take a regular one and turn -or have it turned- down to the required diameter.
Those who do not have that option available, may take an angle grinder to it .
Or even a flat file and a lot of elbow grease if there's no angle grinders around.

When dealing with thin nuts, it also pays to turn/grind the inside bevel on the end of the socket down, that reduces slippage a great deal.
As does choosing a regular socket that sports six flat surfaces, not 12 notches, and definitely not one of those more advanced "gripping" varities.

Regards,
Sam

 

[MidnightArrakis]

I've made with Eagle the re-draw of the Schematics and PCBs of M2000A modules, submodules and power supply, as I'm an M2000/2500 owner.
I've also made a substitution for the Hamlin reed relay.

[I've made with Eagle the re-draw of the Schematics and PCBs of M2000A modules, submodules and power supply] -- Let me try this once again.....2-YEARS LATER!!! -- Could you "PLEASE" either post here or PM to me all of your EAGLE schematic and PCB files??? It would be GREATLY appreciated. THANK YOU!!!

/

 

[glbaudio]

[I've made with Eagle the re-draw of the Schematics and PCBs of M2000A modules, submodules and power supply] -- Let me try this once again.....2-YEARS LATER!!! -- Could you "PLEASE" either post here or PM to me all of your EAGLE schematic and PCB files??? It would be GREATLY appreciated. THANK YOU!!!

/

Why i should? I really don't like your approach...so the answer is NO.

 

[MidnightArrakis]

Why i should? I really don't like your approach...so the answer is NO.

[I really don't like your approach] -- I don't know why you are getting so bent out of shape for someone simply requesting your EAGLE files!!! Other members on here are needing some help with their various projects and apparently you "hold the keys" to what some members need in this thread. All that I am trying to do is to offer my assistance to help them out, but in order for me to do so.....I first need your EAGLE files!!!

I suppose you have the right to be a "Grinch" with your files, but one of the main purposes of this forum is for members to help one another with their various issues and problems. Since I am capable of designing both PCB's and mechanical designs of electronic equipment, I would certainly and gladly share my schematic and PCB files if I had them, but I don't. I don't have the necessary schematic and I do not know about any of the mechanical details of the PCB and I don't know where to obtain them either.

And.....I -- WAS NOT -- going to repost and/or share your EAGLE files in this thread either!!! I was only going to use your schematic and PCB files as a "foundational starting point" in order that I could - start from scratch" - a whole new set of designs by using my own CAD-software, which is also capable of directly importing EAGLE schematic and PCB files (and.....it's NOT KiCAD!!!). From there, once I had redrawin your EAGLE schematic and had redesigned your EAGLE PCB, I was then going to post -- MY -- version of your files in this thread. But.....you wanna be a "Grinch" and prevent * ANYBODY * from improving their AMEK 2500 console projects.....so be it!!! I was merely just trying to offer some help to those that need/want it, but I first need to have something to work from and that comes from you.

[Let me try this once again.....2-YEARS LATER!!!] -- I am guessing that you somehow became offended by my making a comment that I had requested your EAGLE files 2-years ago in order so I could do the exact same thing as I have just reiterated above and you didn't originally respond back then for some reason. I have seen on this forum in countless numbers of threads of members asking other members to post their CAD-design files or GERBER files or whatever, so.....I don't see and/or understand how you can get all spazzed-out for me requesting your EAGLE files!!! People these days get so offended by such little and trivial things. I would hate to live such a delicate life based upon such fragile eggshells that can break under the smallest bit of pressure!!!

I was just trying to help others within this thread and then you come at me with a machete for doing so!!!


>> ENJOY!! << your Christmas.....Grinch!!!

/

>> Examples of what I -- COULD HAVE -- turned your EAGLE schematics and PCB's into:
















>>> What all of these images mean is.....by using your EAGLE schematics and PCB-design files, I -- COULD HAVE -- designed a completely new set of PCB's >> AND << a nifty mechanical chassis (either a rack-mount chassis or a stand-alone type) for those AMEK 2500 users on here that need something like this!!! But.....you don't wanna share!!!.....

/

 

[glbaudio]

Dear Midnight Arrakis,
you have to know I made several workings (restorations) on several audio consoles, and in the past i passed the gerber files to other persons, and somebody have made this:

https://reverb.com/it/item/44348426-mci-500-console-relays-k1
this guy is selling (totally overpriced) a replacing relay board (i maded several for that console, this is one) with my name on it!!! he didn't even have the good taste to redesign it and remove my name!!!

So, you are asking to me to give you MONTHS of my work...on your first message was not written yo have or not an Amek.
I can directly help the guys here, why i should give my job to let you do it on my job? Some of this guys already received my help, Il Fungo for example...ask to him if I'm a grinch!

If you need the schematics i will be happy to help you. If you need some PCB i can do for who ask. If you are searching to do money on my work no.

This is all.

@58Glammer I had some parents problems and i totally forgot you pictures...I'm sorry! here an high resolution of the whole channel

View attachment IMG_2800.JPG

[I really don't like your approach] -- I don't know why you are getting so bent out of shape for someone simply requesting your EAGLE files!!! Other members on here are needing some help with their various projects and apparently you "hold the keys" to what some members need in this thread. All that I am trying to do is to offer my assistance to help them out, but in order for me to do so.....I first need your EAGLE files!!!

I suppose you have the right to be a "Grinch" with your files, but one of the main purposes of this forum is for members to help one another with their various issues and problems. Since I am capable of designing both PCB's and mechanical designs of electronic equipment, I would certainly and gladly share my schematic and PCB files if I had them, but I don't. I don't have the necessary schematic and I do not know about any of the mechanical details of the PCB and I don't know where to obtain them either.

And.....I -- WAS NOT -- going to repost and/or share your EAGLE files in this thread either!!! I was only going to use your schematic and PCB files as a "foundational starting point" in order that I could - start from scratch" - a whole new set of designs by using my own CAD-software, which is also capable of directly importing EAGLE schematic and PCB files (and.....it's NOT KiCAD!!!). From there, once I had redrawin your EAGLE schematic and had redesigned your EAGLE PCB, I was then going to post -- MY -- version of your files in this thread. But.....you wanna be a "Grinch" and prevent * ANYBODY * from improving their AMEK 2500 console projects.....so be it!!! I was merely just trying to offer some help to those that need/want it, but I first need to have something to work from and that comes from you.

[Let me try this once again.....2-YEARS LATER!!!] -- I am guessing that you somehow became offended by my making a comment that I had requested your EAGLE files 2-years ago in order so I could do the exact same thing as I have just reiterated above and you didn't originally respond back then for some reason. I have seen on this forum in countless numbers of threads of members asking other members to post their CAD-design files or GERBER files or whatever, so.....I don't see and/or understand how you can get all spazzed-out for me requesting your EAGLE files!!! People these days get so offended by such little and trivial things. I would hate to live such a delicate life based upon such fragile eggshells that can break under the smallest bit of pressure!!!

I was just trying to help others within this thread and then you come at me with a machete for doing so!!!


>> ENJOY!! << your Christmas.....Grinch!!!

 

[JohnRoberts]

I REALLY DON"T LIKE THE BADGERING.........

JR