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Carlsbro sidewinder all tube - Marshall Mg50dfx 50-Watt Combo Guitar Amplifier

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Which input db to choose for mixer input in carlsbro amp powerline 2000 because there is 3 options +3db 0db -3db, i think 0db is high?

That will depend on what instrument you are planning to plug into it. Set the mains and the channel volume to a low-reasonable level and plug in a play. It the input is distorting, you need to use a lower input level. If it's too quiet, you need to use a higher input level.

Mar 24, 2016 | AMP Music

1 Answer

How do you check the tubes in a guitar amp

A vacuum tube tester is used to test tubes. Years ago, you could walk into an electronics store like radio shack and test your tubes. I suggest you take the amp to good music shop that repairs amps. They will be able to test the tubes.

May 16, 2014 | Fender Vibro Champ Xd Guitar Tube Combo...

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Hi im using the carlsbro gd 4000 in a 3 piece rock and roll band we are using an oldmike shure c606 and we cant get any volume out of the mike and its distorting the vocals we dont know whether the p.a.s...

Proper placement of mics versus the speakers of a PAS is important to avoid feedback. Your speakers need to be toward the audience from where the mic is. If the mic can "hear" the speakers you will likely have feedback. The mic should work even though it is a consumer grade mic.
WORD OF CAUTION: There are a LOT of fake SM58 microphones being sold... even on Ebay... SOME are fairly high quality and others are not.

Mar 31, 2011 | Music

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The output is very low and distorted

The problem is very likely a blown tube. You may be able to see which tube is dead by looking in the back of the amp with the room lights turned low and the amp on. If you can that it is one of the four 12AX7 tubes that isn't lighting up, that one should be replaced. If you can see that it is one of the KT66 tubes that isn't lighting up, buy a new matched pair and replace both at the same time.


If all of the tubes are lighting up, then one or more may be bad, but not yet completely dead. Determining the problem would require more testing. If you have one spare, good 12AX7 tube around, try replacing them one at a time and see if that fixes the problem. TURN OFF AND UNPLUG YOUR AMP IN BETWEEN TUBE SWAPS. If a new preamp tube doesn't fix the problem, order a new set of KT66 power tubes and you should be back rocking out in no time.

Mar 06, 2011 | Marshall Amplification Marshall Vintage...

1 Answer

Why cant i get the same brilliant sound out of this unit compared to a carlsbro cdx 12x2mgs-fet digital reverb (not sure on these exact model nos as reading this second hand) this one sounded awsome ,but...

The mixer should have the same sound quality... the effects MAY be quite different. It is hard to know what you are refering to regarding sound "quality". One must setup the mixer correctly. Critical things are the trim controls and faders. Your faders should be near the unity setting when adjusted. Setting the EQ'a ia important and if you are stereo usage, setting the pan control can be important.

Feb 25, 2011 | Behringer Sx2442fx Eurodesk 24channel...

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My Epi valve jr v3 burns up jj el84 tubes, but the solvteks work it the amp or the tubes?

Check the bias on the tubes! Some brands can run with bias set wrong. Also some amps have 4 output tubes and people don't know that MATCHED pairs have to be seperated to each side of center of the group of four tubes.
You probably only have a single EL84 tube in your unit.
I could not find the schematic for this unit... IF the plates of the EL84 are coloring, the bias is set wrong. The plates should remain BLACK and not coloring to dull red or orange. Telling if the tubes are "burned up" can only be done with a tube checker or electronic test equipment or by seeing a bright purple glow between the elements.
Now this is supposedly only a 5 Watt unit so that means it is for LOW volume practice only... If you overdrive this small amp you can PROBABLY burn almost any tubes you put in it. The sound you can expect out of this will not be louder than most of the consumer boom boxes at full volume.
If you overdrive and "flattop" the unit the power tube will overheat and fail... this amp runs the tube in "Class A" which makes failure under overdrive more likely than in Class AB or B. I can't go into the engineering details other than to say at volumes above the design the output transformer will saturate and the tube will have to dissipate way above its ratings.

Feb 12, 2011 | Epiphone Valve Junior Tube Amplifier Head

2 Answers

I have a Marshall TSL 601. I recently re-tubed my the amp with new Tung Sol tubes and biased per factory specs. With the new tubes installed in both the preamp (12AX7/ECC83's in V1, V2, V3, and V4) and...

First thing is that if you bought MATCHED pairs of the EL34's a COMMON mistake is to install the pairs wrong. Correctely install a pair as the OUTSIDE tubes of the line and then the remaining pair as the middle two tubes of the line of tubes before biasing.

Funny thing, I just ran across this problem you have with a Bedrock brand amp that uses the same configuration as your V3 tube does. This is really a stupid configuration engineering wise as they tie a plate at high voltage to the grid of the second stage in the tube as a cathode follower, This means that the second section has the cathode at a reasonably high voltage relative to the heater with wide audio swings on it as well... Tubes are NOT designed to work that way and result in noisy behavior, One would have to select tubes that have very low heater to cathode leakage in the second section of the tube... What you are seeing is the result of very poor engineering practice. Marshall is probably testing tubes for the leakage and branding them as such...

I think that designers of this circuit have NOT had experience with tubes and have applied transistor type designing to this use... it is plain stupid and myself I would re-engineer the circuit if it was mine or build a tube tester capable of measuring the heater cathode properties to select a suitable tube to use.

Jan 29, 2011 | Music

1 Answer

No volume.

Are the tubes bad? Do they light up? Check the tubes and install replacements if necessary. If it's a preamp tube that went bad, just replace that one tube. If a power tube went bad then replace the set of power tubes. Be sure to get a matched set when replacing power tubes, and to bias them.

Aug 08, 2009 | Fender Hot Rod Deluxe Guitar Combo...

2 Answers

Guitar amp no sound or lighting

Ah yes: complete catastrophe. Usually when everything is not working, it is a single reason and when that single reason is fixed, so is the amp.

Based on what you tell me, I am going to say you have a bad power tube. And I will even go as far to say that you buy a set of tubes and play on them as long as you can. If so, then you not only burned up the tube, but weakened the power section and may have a slooow tube frier. I always tell customers: modern tubes have an effective life of less that 1200 or so hours and that varies. Replace the tubes once per year if you gig with the amp: period. Otherwise, guys like me (doing repairs) stay busy and the tube companies get rich selling tubes to amps with weakened power sections.
It sounds like you burned a power tube and blew a fuse. First, you need a new set of power tubes and some extra fuses (go to Radio Shack and set the value you need in SLOW BLOW fuses).
Then, replace all the power tubes. Don't worry about biasing yet, we are just seeing if there is a problem. Next, replace the fuse.
Turn on the amp and play on it at various volumes and settings. If all is well, take the amp to a tech and get it rebiased. If you can afford it, pay to have the grid/plate and other resistors changed so the power section will be like new (clean slate with new tubes). Your amp will love you for it.
Almost all of the amps I have worked on for performance problems (cant keep tubes to stay alive for very long) are directly related to end user use. When you use a tube until it blows it ALWAYS TAKES SOMETHING WITH THE TUBE WHEN IT GOES (like the power section components). The compents will be weakened and the tubes will 'wear' at different rates that can even move them out of the 20% tolerence they must be within to sound good. 99% of the time a board repair with a retube after a catastrophe fixes the amp until the next time it is 'run into the ground'. Tube amps are NOT invinceble: they are weak compared to solid state and expensive to own. But we love tubes because they sound great. I have solid state to knock around on, when when it counts, I play only with tubes. I have spent hundreds on good tubes because you do get what you pay for.

Hope this helps!

Mar 14, 2009 | Music

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