RM4 with stock modules - ' blanket' effect

[G12]

Hi all

so I have an RM4 with a recto module which I changed a few resistors and caps as per some suggestions I found online.

I also have an SL+ new version.

Both in my RM4. I run this through a fryette 2502 el34 or my 2902 kt88 out to a marshall cab .

They sound 'ok' , ballsy, but sounds like a blanket is over the cab. Has this muddy muffleness about the sound. Sounds nothing like the samples I hear online when used in a rm100 head

Cant be my poweramp cause my soldano and ada mp1 preamps sound crisp and clear.

im thinking its the RM4?

Help. . !!! Is there a fog lifter for the rm4?

 

[audiomidijace]

You might try some high quality, fresh preamp tubes in both the RM4 and the modules.

 

[Corium_AZ]

Yeah, something is wrong there. It shouldn't sound like that at all! Sorry, can't help much beyond assurance that once whatever is wrong is fixed, you won't have that problem. The RM4 I had for a bit was every bit as crisp & clear as my RM100.

 

[Mattfig]

If you want to go really cheap and simple with the tube swap....Focus on your RM4 input tube (closest to the actual input) and then focus on getting one module tubed up fresh and you are on your way....

 

[Corium_AZ]

Actually, yeah, if I were in your shoes I'd rob the tubes out of one of your other pre's & pop em in there, just to see if it solves the issue...

 

[G12]

Hey guys

thanks for the suggestions. Im sure I actually already tried using the tubes from another pre with no real difference to this issue.

ill try a few others too.

I bought this used. Im wondering now if this is why it was for sale. Surely it would be an easy fix.. maybe a cap or resistor needs replacing in the rm4?. I can only assume its not the modules as its the same issue with both.

Keeping in mind my previous thread that my rm4 was modded with that switch. Perhaps this is the issue and perhaps the cap in this section needs a new one to bring back to factory.??

 

[Spencer4hire]

Sounds like a bad density/presence board to me. I am not sure if Jaded Faith or Salvation have the modified boards for the RM4s. I would contact them and see. I installed a Jaded Faith Foglifter in my RM100 and it eliminated the blanket over the speakers tone.

 

[G12]

Hopefully they will chime in soon. I will try the different tubes again tonight.

Its definitely not right at all.

 

[Jaded Faith]

Density and Presence are power amp circuits and have nothing to do with the RM4. These issues are typically only one of the following:

- Bad tube
- Dirty jack/pot/slots/etc
- Broken pot/jack

I have fixed a lot of RM4's and only once have I ever found a bad cap/resistor. Sure enough, it was in a unit someone tried to mod themselves and the cap was underrated for it's position.

I'm not familiar with what mods were done to your unit, but it sounds like someone added a switch to make something variable. The first common stage in the RM4 serves the purpose of being a full-range gain stage that's main role is to simply elevate the signal from your guitar. For your modules to work as intended, this should not be tampered with. It's a utilitarian role and not so much a tone-sculpting one as a conventional amp would have. I'll be the issue stems from said switch and it should be removed cleanly and carefully returned to stock.

 

[G12]

Thanks JF

I had a play with different tubes tonight. No real noticeable difference.

I will disconnect this switch and replace the cap on the PCB to factory value (i emailed you to find out what the factory value is and type of cap etc)

I also have a fellow MTS'r local to me who has offered to try his RM4 with my modules to see if perhaps the sound is normal and as expected or infact there is an issue. He has salvation modded modules so this would be a good test to compare also.

I shall report back my findings

 

[G12]

Hey guys

Firstly id like to say thank you to all for assisting and taking the time to reply. But specifically to a fellow MTS member and friend who was kind enough to spend his time on the weekend to use his RM4 and modules as tests.

Also to Rob at Jaded Faith who took the time to reply to my emails and assist with something that isnt his problem but was very helpful with suggestions.

so an update.

Ok so tried my friends RM4 with my modules and they sounded the same essentially. I tried his modded modules through my RM4 and they essentially sounded the same as his RM4.

He happened to have a brand new JJ 12ax7 and we tried it in my RM4 in V1 and this made a noticeable difference to the tone. Sounded alot better after this with the SL+ module (later model stock version). The recto module sounded crap all round so i think there are some issues with that module (maybe tubes or electronics)

So it would appear that my RM4 is ok and working as expected.

So back to what made me think something wasnt right. My SL+ sounds quite crunchy which was completely different to the stock SL+ sample online which i thought sounded awesome and appears much more gain/saturation and exactly what i was after:

This is what made me want the SL+ module:

http://www.bandslink.com/randall.htm (click on SL+)

My stock recto sounds nothing like the recto sample either. So thats why i thought perhaps it was the RM4. My recto sounds like a crunchy version of the SL+ whereas the sample sounds like a recto. Its possible the recto module has some faulty components as it sounds really bad as far as tone goes. Not usable at all.

My modules sound like they are only "half" of the sound that the samples are, like there is a lack of something from them. I wonder if perhaps new tubes might make some difference but im not sure it would make a difference enough to make them sound like those samples.

ROb has given me some suggestions for Tubes. So i might go and buy a whole bunch and retube my other preamps too. i may be robbing myself of tone from these too considering my experiences above.

Does anyone have a Stock SL+ (later version) that actually sounds close to the sample?

thanks all.