RB1080 modified ???

[calmac]

I have just had my 1080 returned from repair after one of my cats mistook it for it's litter box!!!.
The amp sounds awful compared to my memory of the sound pre-cat and so I decided to do a bit of internal inspection to see if anything was amiss.
The only thing that looked a bit odd is that there are now a resistor and small mylar looking cap connected in series with each other across the positive and negative speaker terminals on both channels.I don't remember these being there before the amp went in for repair and was wondering if this could be at least part of the problem.Is this perhaps the mod to make the amp more resistant to blowing channels or have I just never noticed this before.It does look the mod has been added post production???
Any help will be greatly appreciated.
Gordon

[JDH]

Your better off contacting the Australian distributor direct, I had my RB-1080 modified adn it didn't sound any different after the modifiaction, but it did solve the blown fuse issue.PM me if you want the contact details of someone to contact within International Dynamics.

[Marlboroman]

You just failed to notice that before. The is called a Zobel network and is present on this type of amplifier.

[calmac]

My problem is that the 'mod' didn''t look like something Rotel would have put in the amp and having removed it the sound seems to be less bright and hard although still not right.
What is the purpose of the Zobel network and could it have been negatively affecting the sound or am I just falling into the placebo trap.The amp seems to be working fine without the network.
Gordon

[calmac]

My problem is that the 'mod' didn''t look like something Rotel would have put in the amp and having removed it the sound seems to be less bright and hard although still not right.
What is the purpose of the Zobel network and could it have been negatively affecting the sound or am I just falling into the placebo trap.The amp seems to be working fine without the network.
Gordon

Just Googled Zobel networks and it looks as if these components are perhaps the after manufacture mod for 1080's that were blowing channels.I have never had this problem with my amp and the effect on the sound quality appeared to be the reverse of the effectthat Zobel networks are supposed to have i.e reduction in bass output and increase in midrange and hf output.I have had a look at the schematics for my speakers and these contain a Zoble network in the passive crossover anyway which makes me wonder if the two ZN's were having some sort of negative interactive effect.
Gordon

[calmac]

Just Googled Zobel networks and it looks as if these components are perhaps the after manufacture mod for 1080's that were blowing channels.I have never had this problem with my amp and the effect on the sound quality appeared to be the reverse of the effectthat Zobel networks are supposed to have i.e reduction in bass output and increase in midrange and hf output.I have had a look at the schematics for my speakers and these contain a Zoble network in the passive crossover anyway which makes me wonder if the two ZN's were having some sort of negative interactive effect.
Gordon

ops: ops: Well much to my embarassment I have discovered what the remaining problem was.When I put the poweramp back in the rack after removing the mod I managed to reverse the left and right channels.Normally I run the channel test to make sure I haven't done anything daft but I had removed the tv from the room and therefore couldn't use the setup menu on the 1066.I reconnected the monitor and discovered my mistake.
The system now sounds like it should for the first time since the cat got involved which makes me wonder if the enginner that repaired the amp got the component values for the mod wrong or just inserted it in the wrong place ,as I can't see Rotel authorising a mod that would have such a negative impact on the sound of the poweramp.
Thanks to those who attemted to help , finally I can get back to just enjoying my music.
Gordon

[Azeke]

Calmac,

Don' be embarassed we all make those kind of sophomoric mistakes (Cable 101). Glad to see your amp is up and running properly.

I want to send my 1080 for authorized mod repair, but I don't want to be without it for any period of time, so I just leave it on, to eliminate my fuse blowing issue.

Peace and blessings,

Azeke

[Azeke]

Pulling this thread from antiquity to provide a 1080 update:

Since I had to repair the 1098 for a LCD issue, I decided to finally send my RB-1080 for the mod repair, specifically to resolve the fuse blowing issue. I've been running it for a couple of months now utilizing the 12v trigger, and so far so good (I trust I didn't jinx myself).

Peace and blessings,

Azeke

[calmac]

Good to hear Az,I ended up replacing the 1080 with a new one and having to rebuild the crossovers in the speakers to finally recover from the damaged caused by the cat.
Gordon

[Azeke]

Good to hear Az,I ended up replacing the 1080 with a new one and having to rebuild the crossovers in the speakers to finally recover from the damaged caused by the cat.
Gordon

Gordon,

Sorry to hear about your tail of woe ;-), but glad to hear that you are up and operational :T .

Thanks and best regards,

Azeke