New (to me) 5:50 plus hiss

Hi all

I'm looking for advice on a 2nd hand 5:50 plus I just bought from the local dealer. According to them the amp is three months old and had been sold to a person who didn't get on with it and ended up going with a Lonestar instead.

Anyway, it seems to me that the amp has fairly loud hiss (S.C. or H.B. makes no difference) and a weird infrequent popping noise, as well as a loud thumpy pop when switched into standby (also the loud pop when switching channels and one of them is on 5 watts - but I knew that was a "design feature").

Normally I'd just take it back to the dealer and ask them to look at it, but I know (after a long saga troubleshooting a new deluxe Tele earlier this year ... I've been very very good and very lucky...) that there are weird electrical noises happening in the airwaves at my place that some pieces of equipment (like the Tele) pick up like antennae. Because they're coming via the environment, they're hard to quiet ... but I digress. Anyway, the weird electrical noise in the house thing makes me wonder whether it's worthwhile taking the amp back to the shop for a look - ie it may not be faulty, it may just not be dealing particularly well with its new environment ... or that behaviour may be normal.

So three questions really.

1. Is noticable hiss normal (eg on, say, crunch with gain at about 7:00 (ie hardly any)?
2. Is the popping behaviour normal?
3. Is the hiss issue one that may be evident even with new stock tubes (ie should I forget going back to the dealer for diagnosis and just go with a retube using, say, Doug's tube recipe).

Apologies in advance if there's an answer to this somewhere I didn't find. Most posts I did find said the hiss issue from the original series is absent from the plus series, which left me unsure whether this meant the hiss was outside of spec or whether the spec and my expectations did not meet.

Anyway, TIA for your assistance in settling a new parent's nerves

ru32day

My 5:50+ developed a small bit of hiss recently. I replaced the V2 spot with a Mesa SPAX7 and the hiss is now gone. The only pops I have is when I switch the EQ on/off with the footswitch on channel one. It only pops the first time and I've found that if I switch it on/off while my amp is in standby warming up I do not get any pops. I'm assuming there's a bit of static that gets discharged.

Thanks for that advice, Jeff - I'm now thinking there could be a combination of factors at work in my case.

I might try an EFI/RFI filtered powerboard for the random pops and maybe a hiss reduction and go back to the dealer for assistance on the standby pop and general hiss issue.

Almost worked up the bottle to try some tube rolling into the V2 spot, but lost my nerve. Maybe I'll feel brave again tomorrow.

Cheers

ru32day

Changing tubes is the easiest thing you could do.


http://mesaboogie.com/news/2010/11/mesa-amplifier-tube-troubleshooting/


http://www.mesaboogie.com/US/Dealers/FAQs/faqs.html#diagpre

And changing tubes with Doug's Tubes is a smart choice!

More really helpful advice. Thanks heaps. Bottle slowly returning I think

I've been lucky, the only time I get a "popping" is if I change wattage on a channel when the amp is not in standby. If changing tubes doesn't fix your hiss, a simple fix might be to get a noise gate pedal in the loop.

Tubes on way from Doug. Will report result.

EFI/RFI filter does seem to be helping a bit. No random pops yesterday, but since they're infrequent anyway, that could be coincidence.

Agree that noise gate in the loop would be the final option. Hope it doesn't come to that.

Well it's done.

Ordered tubes from Doug on Thursday night and they were delivered to my home during the day on Monday. Unremarkable you might think, except I live in Australia! I've had stores over here take longer than that to get around to mailing something, let alone having it on my doorstep. I'm hugely impressed with the service. I had eMailed Doug earlier for advice and his response to that was super quick too.

Anyway, did the deed tonight (with much trepidation) and the clean channel is now silent on very low gain and very quiet when the gain is increased. The blues channel is noisier in comparison, but not badly so, just not totally silent.

Previously I wasn't hugely impressed with the 25 watt setting and tended to go with 5 or 50. Now 25w sounds fantastic!

The amp has moved one further step back from the edge of ice-pick (previously it very narrowly avoided ice-picky on occasion). Counter-intuitively, the amp seemed a little "colder" sounding to me overall though and I felt the bass a little less in my body.

So I tried the EQ out. Had it sounding just as I wanted in seconds and good old feeling in the belly returned. Weird ... before the tube swap I preferred the un-EQ'd tone and couldn't dial in an EQ'd tone I particularly liked at all.

Anyway all has ended very well. Quiet amp, perfect tone, all power settings now sounding great, happy camper! Thanks for your advice and encouragement. They really helped the nerves

ru32day said:

Well it's done.

Ordered tubes from Doug on Thursday night and they were delivered to my home during the day on Monday. Unremarkable you might think, except I live in Australia! I've had stores over here take longer than that to get around to mailing something, let alone having it on my doorstep. I'm hugely impressed with the service. I had eMailed Doug earlier for advice and his response to that was super quick too.

Anyway, did the deed tonight (with much trepidation) and the clean channel is now silent on very low gain and very quiet when the gain is increased. The blues channel is noisier in comparison, but not badly so, just not totally silent.

Previously I wasn't hugely impressed with the 25 watt setting and tended to go with 5 or 50. Now 25w sounds fantastic!

The amp has moved one further step back from the edge of ice-pick (previously it very narrowly avoided ice-picky on occasion). Counter-intuitively, the amp seemed a little "colder" sounding to me overall though and I felt the bass a little less in my body.

So I tried the EQ out. Had it sounding just as I wanted in seconds and good old feeling in the belly returned. Weird ... before the tube swap I preferred the un-EQ'd tone and couldn't dial in an EQ'd tone I particularly liked at all.

Anyway all has ended very well. Quiet amp, perfect tone, all power settings now sounding great, happy camper! Thanks for your advice and encouragement. They really helped the nerves

Click to expand...

So.......have you noticed any other differences on sound when you switched out to Doug's Tubes? Did you change the pre-amp tubes too?