RSX1055 BM fix!

[Andrew Pratt]

Ok I hope to try this as soon as I can but it may take me a week or longer to find the time...but for those with 1055's here's what you need to do to remove the bass redirect on the multi channel inputs

Find the Terminal board marked 016V-1339V301 and disconnect resistors RW 167 and RW 170.

I think I'll install a toggle switch like someone else did on their 1066 when I get around to doing the fix.

[TonyPTX]

Guidance from Rotel no doubt? Anyone have any board schematics?




"Those that don't know, don't know they don't know."

[Kevin D]

Everything in there is marked pretty good. I'm assuming the hard part would be finding the right board..

*HINT* Start at the multi-inputs and work your way back..

Kevin D.

[Andrew Pratt]

Well I just couldn't wait so after work I stopped by Radio Shack and picked up a switch similar to the one you bought and proceeded to unplug everything and do the nasty on it One thing I noticed right off the bat was that at least on my 1055 the board number was different then the number given above which I assume stems from the version 1 vs version 2 models (I'm trying to confirm that) but regardless the little (and I mean little) resistors are easy to find and gaining access to them isn't to bad. I removed the tuner card as well as all the wire plugs so that I could remove the board completely from the case. I then did exactly the same proceedure as outlined in the 1066 upgrade thread and installed the switch above the firmware upgrade dip switches. One word of caution here is that there isn't much room to place the switch since the tuner card occupies some of the room on the back corner so don't buy too large a switch Anyway I've been testing it with some DVD-A and CD titles and with the sub set to On in multi channel mode if I flip the switch I can hear the sub where as turned off its quite so I'm pretty sure its working properly.:T I took a few pictures of the process but its late so you'll have to wait till the weekend before I get those online

[sdecker]

Andrew,

Cool, I figured that you would do this sooner than later. Do you have the board number for a ver 1 1055(1.49 firmware)?

Im hoping to do this mod this weekend, but will probably wait until your pics are up.

Im not adding a switch, as I cant solder for S**T. So I can just cut one lead on each resister, cirrect?

TIA

Earle

[Andrew Pratt]

Sure if you are just cutting leads you won't even have to remove the board so it will be super easy. Yes I have a 1.X board in my 1055

[TonyPTX]

And how does this affect the warranty from Rotel?




"Those that don't know, don't know they don't know."

[Andrew Pratt]

It doesn't effect the warrenty providing you don't mess anything else up. i.e. if you simply go in and snip the two resistors Rotel won't care...but if you snip the wrong ones then expect Rotel to fix it for free you're out of luck. So my advice is if its something you really want done and either feel comfortable doing it yourself or you have someone that can do it for you then its easy and safe but if you have doubts don't do it.

*Tony please remove your equipement list from from your signiture and move it into your profile instead. The problem with it in a sig is that if someone does a search for Rotel it will find every single one of your posts even if its not applicable to the query.

[sdecker]

Thanks. Ill post when its done.

I cant wait to see Andrew's pics of the mod.

[Andrew Pratt]

Alright I appologize for the quality of the images and how brief this is but I'm pressed for time and I know some of you wanted to get started this weekend so here goes...

I left these all as very large images so sorry for those on dial up but I wanted to leave as much detail as possible...

To get started we need to remove all the wires from the back of the receiver. I took a photo of the wires in case I needed a reference and marked each cable with a marker (non permanent) with a letter code just in case

Next we need a level and safe place to put the receiver. This is pretty heavy so make sure its a solid stable work surface that isn't to dusty or any chance of water getting spilled on it etc. You will need a philips screwdriver (cross) to remove the four screws on each side of the receiver as well as the two smaller ones on the top of the case as shown in this image here I've also marked the locations of the switch position and the screws you're going to need to remove if you want to remove the board later on.

If you are simply going to cut the two resistors you don't need to remove the boards just locate the board and then very carefully snip one side of each resistor. The board you're looking for will be marked with the board ID code which should be something like 016X-133339A01 if you have a first generation unit or the code I posted above for second generation units. Eitherway its easy to find since its the same board that has the Component inputs on one end. This image here. That's what it looks like where you're finished but it nicely shows the location of the board and resistors.

Now assuming you wanted a switch installed read on...

You are going to need to remove the tuner board first to gain access to the board we need to work on. There's only one screw holding the tuner board in place and its located on the left hand side as illustrated here. With that out of the way you now need to remove all the screws holding the 016X-13339A01 board in place. This image has them all marked for you. You will also need to gently remove the wire harnesses from the board. These will come loose with a little wiggleing but don't force them! Don't worry about trying to remember which goes where since they'll "remember" where they go and the wires are all cut to the right lenght so its not a problem. Now with the board removed you need to find the two resistors and unsolder one side of each resistor following the methodology set out in the 1066 upgrade thread.

I used a simply DPDT switch from Radio Shack that was $3.99 I believe and some CAT5 cable I had around. Anything similar should work fine and the instructions on the 1066 upgrade thread were a great help.

Here's what my switch ended up looking like with the CAT5 cables soldered in place and here's the board with the wires soldered to the resistor lead and to the board. Again the instructions in the 1066 thread were very helpfull in this process.

That's about it for now...Lauren's crying and we're heading out for a 95th birthday party so I gotta go

[sdecker]

Thanks for the pics Andrew.

This was the most nerve racking thing Ive ever done with my stereo. Nothing like cutting 2 resistors in your receiver.

The BM fix was easy if your just cutting the resistors, as I did. I unplugged one of the cables on the card to gain easier access to RW 170 resistor, otherwise it was literally 2 snips with a pair of small diagnols.

Now I think I have the perfect receiver/preamp. My multi-channel SACD's sound cleaner now, the bass is less thick now, for a lack of a better term. CD's being played thru the multi inputs cleaned up the same way.

Trust me if I can do this mod, anyone can. Thanks to Rotel and our hardworking moderator Andrew.

Earle

[MiguelR]

Guys, I just got my new 1055 and I've been reading a lot around this BM problem and fix. I must confess that I'm a little scared at the though of opening my receiver and cutting a couple of resistors inside it!

So before taking the plunge, I'd like to understand exactly what the problem is and whether it will affect me with my planned setup.

Could someone please describe the problem precisely, including which modes it affects? I know it has to do with the analog inputs, but does it also affect any digital decoding? What about 2-channel via the analogs?

Thanks a lot in advance!
Miguel

[sdecker]

Miguel,

If your 1055 has the current firmware, 1.49 or 2.25, there are no problems with BM except with the multi inputs.

The multi inputs still have the bass doubling until you do the BM mod. It is really easy to do, just take your time and make sure you cut the proper resistors.

The bass doubling issue is:

When you use the 5.1 inputs the 1055 takes all bass(<100hz)from the R/L/C/SL/SR channels and sends it to the sub. The problem is that it that it doesnt remove the bass from the other channels, hence the double bass.

Most people feel that the 5.1 inputs should be a total analog bypass with no BM, or at least allow the user to decide whether to impliment any BM.

Hope this helps

Earle

[MiguelR]

Hi Earle, thanks for your reply!

If your 1055 has the current firmware, 1.49 or 2.25, there are no problems with BM except with the multi inputs.

I just checked, and my firmware is version 2.2.2. Would it be worth an upgrade first?

The problem is that it that it doesnt remove the bass from the other channels, hence the double bass.
Most people feel that the 5.1 inputs should be a total analog bypass with no BM, or at least allow the user to decide whether to impliment any BM.

So which of the two does the BM fix attain? Does it remove the bass from the main channels, or does it remove BM altogether from the analog inputs?

I really want to understand this thoroughly before performing the surgery :? Hopefully tomorrow I will get my SACD player, so I'll be able to do some experiments and judge for myself.

Thanks guys! This is a great forum.
Miguel

[Andrew Pratt]

Upgrading the firmware will fix the bass mangement issues on the digital side and allow you to turn off the sub if need be for the analog inputs (CD player etc)

To remove the bass management from the multi channel inputs you need to do the hardware fix on the two resistors. As mentioned above this will remove the added bass that gets sent to the subwoofer on the multi channel inputs so with the fix they'll function as a true analog by pass which is what we want for DVD-A and SACD

[bresna]

I have started to get more and more into multi-channel audio and I've decided that now I have to make this surgical strike on my RSX-1055 to fix my bass doubling. Any chance that someone saved the photos from this post? Wherever Andrew was storing them has goone bye-bye. I'd like to do this but I'd really like pictures.

Also, am I reading this thread correctly: after I cut these resistors, the subwoofer will no longer be getting any signal if I select the "Multi" input?

Thanks,
Kevin

[Andrew Pratt]

Kevin I think I've still got those on file somewhere. The subwoofer will now only get a signal if your DVD player (or SACD player) sends it a signal either through a dedicated channel or by its own bass management setup.

[Andrew Pratt]

here's the image you need.

[bresna]

Thanks a bunch Andrew.

Kevin

[bresna]

So today we're getting another foot of snow today and rather than go stir crazy, I decided to surgically alter my beloved RSX-1055. Scary stuff when you finally get to the cutting!

My unit had the older board so the picture didn't match... you can imagine how scared I got then! Anyway, snip-snip and back in the system it went. I put on an SACD an voila, no sub signals. Excellent. I then put on a DVD and bam, there was the bass. I am happy now.

Thanks Andrew for getting this fix for us.

I do have a question about the level difference between the mulit input and the coaxial digital input. Are they usually very different? My wife hates the sub and would love to watch movies without it. I put on Star Wars Episode V and played the THX intro. The difference between the two was indescribable. The multi input was very weak with almost no bass. I checked my CD player (a Pioneer Elite DV45A) and made sure my speakers were set to "Large" and I had the subwoofer set to "none". Everything looks OK. Should I check something else or just expect that the multi input will have a much lower volume?

Kevin

[Big Kev]

Hi To All,

I have been reading articles on the forum for some time now and find it to be of great help.

I have been reading the BM fix and was worried that if i performed this mod that i would then miss something in the sound.

Well, after buying Santana's Supernatural & Shaman DVD-A discs, i thought that there was too much bass. Procrastinating for 3 hours over performing this mod, i decided to do it.

To say it sounds a s**t load better is a graphic understatement. The sound is so much more focused and clear. I recommend this mod to any who use the Multi Inputs.

Thank You to all for the interesting reading & info.

[bresna]

Big Kev, it is nice isn't it? I am really enjoying my multi-channel music discs a lot more now. Before this mod, I would just "live with" the bass doubling and if I got really bad, like it did on some rock discs, I'd get up and shut off the sub. This is much easier.

BTW, even with the lower volume and lessened bass with the multi inputs, my wife is still going to use them for movies (when I'm not watching one!). She just hates the sub. I don't understand it.

Kevin

[seowfun]

I'm getting a DVD-A/SACD palyer, and I would need to use the multi-input of my RSX-1055. I got my RSX-1055 later October 2003. Does it still have the double bass problem? When you guy said snip the resistor, does it mean cut both end of the resistor to completely remove it from the board, or just cut one end of it, and leave the resistor on the board?

Another question for multi-input is I understand that the receiver will not perform bass mgmt or delay/distance adjustment on multi-input. What about level adjustment for L/C/R/S speakers? Does the general system speakers level adjustment still apply? I know there's an additional option to adjust the level for subwoffer specifically for multi-input.

Thanks!

[Kevin D]

All 1055's had the double-bass setup. When you snip it, just snip one side and pull it away from the board slightly.

Level adjustments also do not apply to the multi-inputs. You will need to set up the levels and delays in your DVDA's setup menu.

Kevin D.