bENDER
Greetings everyone!
This is the second time I have hit a major [hopefully not] snag with my Randall RG200. The first one made a stange humming noise after I had it for like 3 weeks and the supplier replaced it. NOW after about 5 months the "new" one freaked out...I was jamming when it made a noise similar to someone falling onto a drum kit with your head hitting the bass drum last and then silence... ☹. This is really starting make my blood temperature rise!
The master volume has never even gone past 4/10 and not impacts of any kind! I can't think that I have damaged anything.
Do you guys think back to the supplier? >☹
AlanRatcliffe
Absolutely! If it's under warrantee, it is the suppliers problem, not yours. If it's a valve, it might not be covered (many manufacturers will only guarantee valves for three months), but otherwise you're golden.
bENDER
Thanks for the advice...back to supplier, now I must just wait for the outcome. :-\
bENDER
It's taken a while...be we African's are gelukkig very patient!
The workshop tech says that the woofer [suppose he means speaker] has blown and then some more electrical goodies. He thinks it might be a short on either my cable or my guitar or both!!! Is this possible? My other amp is still going stong.... ???
Gearhead
He's joking about the guitar. Your guitar, when you're not playing or when you turn the volume down, IS a short. The amp amplifies the signal, even when it is 0 (as in shorted to ground).
He is not likely to be right if he's referring to the speaker cable (if he is) since this would not blow the speaker. At best, there's a remote chance you might damage the OPT.
On the other hand, a blown speaker poses a very high impedance to the OPT and could easily destroy stuff.
If you can, try measuring the DC resistance of the speaker. If it is 3-6 ohms, just test it with another amp, gradually building up volume. If it is some high value, he's at least right about the speaker. He must just explain why it has blown during the warranty.
My advice: Ask for a written report and see what happens. The guy's not going to know who you're taking the report to, so he must stop talking nonsense.
If they won't give you the report, ask for a second opinion and take it to a proper tube tech.
bENDER
Thanks Gearhead.
I have so many questions...sorry for bothering!
+ This RG200 has a single 12AT7 valve that drives the first 2 stages of the Mosfet output cicuit [according to the 1 page booklet that came with it], do you have to replace this valve like with valve amps?
Can you give me some tips on maintenance & preventing shorts, maby just like general pre-cautions. I am really starting to dislike the amp for this unreliableness...It sounds FRIKIN WICKED, but if it brakes the whole time... >☹ and it's not like I am abusing the amp...maby I should wind it....hehehe...punish me master!
I hate it when I feel so helpless...feels as if my hands are cut off....
Gearhead
Firstly, my bad, I got it wrong about the OPT. I looked up the schematic when you started the thread and did not bother to look again. The thing does not have an OPT since it's FET based. It will NOT like a short in the speaker cable (solid state amps may very well blow, tube amp is likely to live through it).
Secondly, your preamp tube is going to need replacement just like any other preamp tube, which is once every 3000 hours or so (I might be a factor of 2 off either way depending on the tube and the schematic). Preamp tubes last a lot longer than output tubes.
It is worthwhile to buy a new tube however, stock tubes tend to be cheapies. You might like the ElectroHarmonix 12AX7EH for aggressive lead tones and less bass. In any case, swapping the tube ('rolling', a matter of pulling the old one out and pushing the new one in) will help you find the tone you like. You need a spare in any case.
For care and maintenance, look at the sticky posts at the top of the amps section.
bENDER
Shot Gearhead!
Got the amp back yesterday, so far so guud. The report says that the output FET's had blown...they replaced the amplifier module...
G-Man
Sorry to perform the zombie ritual on this thread but I have a Randall rg200 g3 and it too has started buzzing, especially in high gain channel 2. How has your amp been if you still have it and did you swap out the tube? I will try replacing that first and then take it from there.
bENDER
Hey G-Man, whahahahaaaa, so funny, since I moved the Randall to the band room and dosing it with some good death metal medicine, no issues...it actually sounds frikin good. It's even acquired some "war" scars after using it in a few GIG's...(Still hunting for the person who scraped & bumped it... >☹ )
The gain channels on the amp are a bit noisy, especially the 2nd, but "normal" noise I'd say, when I turn the 2nd gain full & crank the volume it is a bit out of control (do you make use of a noise suppressor?). The guitarist in our band runs effects through the clean channel, the gain on the Randall is not brutal enough for him....RECORDING nightmare! ? But I like the gains on the Randall for other purposes.
I have not replaced the pre-amp tube, will check that in future.
P.S. Check your main power source, have found that the Eskom power supply fluctuates & stuffs around with the amp sound.
Hope it helps!
G-Man
Oh thanks man that makes me feel a bit better, I do get a bit of buzz at high volumes on those gain channels but the buzz got really loud last practice. I don't have a noise gate or compressor unfortunately, just a volume pedal but even that wasn't helping because the amp was buzzing without any sound coming from my pedals or guitar. Another funny thing was that my volumes were so low on all channels.
So I stuck a 12AX7 in and pulled the old JJ ECC81 out this afternoon and I must say, the volume is back to ear bleeding levels and it just sounds so much warmer, really digging it so far!
Shot for the help!
bENDER
Hehehe, plesier! Thanks for your feedback, I am also going to experiment with the tube as soon as I get a chance. That low volume & noise was obviously caused by the tube that was stuffed, I have a similar issue with my Ibanez TSA-5 [Problem with the power amp tube]...4 frikin months later & still waiting for a 6V6GT tube from a shop!
G-Man
A little tip about the tubes, my local music store wanted to charge me 360 bucks to order me the tube so I looked at rs components and found it for 80 bucks. Sure it's a chinese made tube but I could buy another 3 as backup for the price. And it came the very next day! ?
AlanRatcliffe
bENDER wrote:
...4 frikin months later & still waiting for a 6V6GT tube from a shop!
That beggars belief. Just contact Mr Valve and you can have most any valve within a day or two.
