Carr Sportsman - bought yesterday and it has a strange buzzy overtone

Sharky77

The amp sounds incredible with the volume low and the headroom high, no background noise at all. As soon as the volume is at 11-12-1 o clock and it starts to break up this weird buzzy sound happens on top of the guitar tone. As you can hear in the videos it dies away before the main guitar tone. I've tried it into an external cab and it still does the same thing so it's not cabinet or tube rattle. Anyone out there heard this before? 

The guy I bought it from had a full set of JJs installed last year by an amp tech when one of the original 6V6s went. Strange that the amp works so perfectly when it's not breaking up. 

Any help would be hugely appreciated!

Couple of videos at the link below, they won't embed for some reason

https://imgur.com/a/jpa3JuI

Th4fonz

Ok I know this may sound stupid but is there nothing vibrating in the room books or something?  I’ve definitely had a weird noise before and it’s been one the radiator vibrating on the wall from the noise and something on my shelf.

Sharky77

Definitely not that as I've switched rooms and switched houses so it's been 4 rooms so far. It doesn't sound like something is rattling either, it's coming out of the speaker. I've also had stuff vibrating in the room many times with amps and you can track it down. This is different from that.

Thank you for chiming in though @ ;

Much appreciated!

allen

I had a problem with my Carr amp. I emailed Steve Carr and he replied very quickly and really helped me trouble shoot it. He even helped me replace a cap (small one!) and stuck with me through the entire trouble-shooting process right the way til it was sorted.

If you send him the video I am pretty confident he will do what he can to help you sort it.

marlinman

Almost sounds like a rattle inside the cab but I assume you’ve checked for that.

You could try asking Steve Carr for some advice, he has always been super helpful when I have had questions on stuff regards my Carr Skylark.

Nobody will know more about the Sportsman’s possible issues than Steve.

ChrisCox1994

it could be valve seating maybe?

Sharky77

I emailed Steve yesterday and am waiting on a reply, thought I'd try here aswell as I know lots of people here are very knowledgeable and have owned Carr amps. 

I think the fact it happens into an external cab rules out cab rattle. It also isn't volume dependent, it can be loud with the headroom control turned up and it doesn't do it. It's related to when the amp starts to break up. 

Thanks for your help guys!

Sharky77

Checked all the vales and they are seated properly 

Winny_Pooh

Check valve seating then try a different speaker. 

donbot

Have you tried with the reverb all the way off? 

Sharky77

Checked valve seating, 2 other speakers and the reverb all the way off.

Steve did reply but seemed to just imply it was normal to sound like that.

He said it was better to run the volume low and headroom high and use an overdrive pedal but one of the reasons I bought this amp was to be able to set it at the edge of break up. 

In the demos I've heard of it people push the volume and it sounds great. Also in the manual most of the presets have the volume turned up and the headroom low. 

If anyone has one of these amps and can chime in I'd really appreciate it

MikeP

Don't know the amp, does it have power scaling? Breakup at low power can get weird...

Modulus_Amps

You say it doesn't do it with the headroom control up high or higher? So high headroom setting and on the edge of breakup.

The trail sound is horrible, it could be a faulty part or could be related to the headroom control implementation. The fact that Steve has said to use an OD pedal makes me think it is something inherent in the design

I suspect the headroom control is a voltage control for the power amp. It would also need to adjust the bias voltage for the power amp since it is fixed bias. When you change the voltages in the power amp it could affect the harmonics and overtones as the amp moves away from its intended operating point.

smigeon

This sounds a bit like a problem I had with my Carr Viceroy. It was eventually fixed simply by replacing the 6L6’s.

Wazmeister

Olly, my first thoughts was that it was a value problem...

However, I would check the amp seating screws into the cabinet itself, and the handle screws. I'm sure that you have already done this.

None of my Sportsman (men) made this noise, and the break up was superb.

I would maybe change the power tubes.

Sharky77

Thanks everyone for your comments and suggestions - really appreciate it!

It seems the Sportsman is both fixed and cathode bias. @Wazmeister do you know if I can put in some new 6V6s without having to rebias? About to order a pair of TAD 6V6GT STR Redbase to replace the JJs

MikeP

Modulus_Amps said:

You say it doesn't do it with the headroom control up high or higher? So high headroom setting and on the edge of breakup.

The trail sound is horrible, it could be a faulty part or could be related to the headroom control implementation. The fact that Steve has said to use an OD pedal makes me think it is something inherent in the design

I suspect the headroom control is a voltage control for the power amp. It would also need to adjust the bias voltage for the power amp since it is fixed bias. When you change the voltages in the power amp it could affect the harmonics and overtones as the amp moves away from its intended operating point.

Err, that's what I just said, isn't it, err,  just with clarity and knowledge... and expertise...

Wazmeister

Sharky77 said:

Thanks everyone for your comments and suggestions - really appreciate it!

It seems the Sportsman is both fixed and cathode bias. @Wazmeister do you know if I can put in some new 6V6s without having to rebias? About to order a pair of TAD 6V6GT STR Redbase to replace the JJs

The manual link is here mate;

https://static1.squarespace.com/static/601888bcfc7ec86a753648e1/t/625c3e05a3f00554fbf38090/1650212358656/Sportsman+.pdf

"Biasing your Sportsman

The Sportsman utilizes a mix of cathode bias (self bias) and fixed bias and as such does not require a bias adjustment when changing tubes. Please use well-matched pairs of output tubes for maximum performance. The Sportsman can only use matched pairs of 6V6 power tubes."

JezWynd

It sounds like a volume induced vibration to me. Sound dies away as volume fades. Could be valves but more likely something loose in the amp or cabinet.

Sharky77

JezWynd said:

It sounds like a volume induced vibration to me. Sound dies away as volume fades. Could be valves but more likely something loose in the amp or cabinet.

@JezWynd ;As stated above it makes the same noise into an external cab so it's definitely not anything loose in the amp or cab that is rattling. I've experienced that many times and this sounds different. 

@Wazmeister thanks mate I realised as soon as I had asked you that it would probably be written in the manual. Thanks for copying over though! 

I've replied to Steve - will update the thread if the new tubes resolved the issue. Annoyingly all my other amps are 6L6s so had to order some 6V6s - hoping that solves it

GavRichList

I just had issues with JJ 6V6s rattling. I think they might be junk. Long story short; bought some TAD 6V6GT-STR’s and lo and behold, the issue resolved.