A new start for my DC3

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gromousse

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Hello ! Forgive my poor English, I'm French. I own a DC3 since 1995. The tubes were changed only one time about 1997 I think, I don't know what tubes are inside now. I've always suffered from some issues as bad ground noises, most depending on the quality of ground in the house I think. I also have problems with reverb which is good on rythm channel but tiny on lead channel. I have some questions.
- is it a good idea to change the tubes ? I think so. What can I choose ? I've herad about Electro Harmonix russian 12AX7 for preamp, and sovtek EL84 for power amp. Can you explain further ? Will it change the sound ?
- can I do something for the reverb or is it normal ?
- do you have any solution for ground noises ? A conditioner ?
- is there anywhere banks or examples of sounds, personal settings ?

I left my amp alone for some years, and now I want to get it relive ! Thank you !
 
Well, if the tubes are 17 years old and were used for any decent length of time, changing them with ANY new tubes would be a start. Several people on here have said to check out Doug's tubes online. I have had good luck with JJ tubes from Eurotubes myself. Defintely start with new tubes. Enjoy! :)
 
Ok, so I will search new tubes. Do you have any advise for me on the tubes ? I don't need too much gain, I play at low level generally. I own a fender strat 78's and a Yamaha RGX, Ibanez-style with Seymour Duncan humbuckers. I play blues, rock, no deathmetal. I'd like to find rich sounds but not too much overdrived, such as Pink Floyd, Mark Knopfler, or bluesmen S.R. Vaughan &co...
 
gromousse said:
Ok, so I will search new tubes. Do you have any advise for me on the tubes ? I don't need too much gain, I play at low level generally. I own a fender strat 78's and a Yamaha RGX, Ibanez-style with Seymour Duncan humbuckers. I play blues, rock, no deathmetal. I'd like to find rich sounds but not too much overdrived, such as Pink Floyd, Mark Knopfler, or bluesmen S.R. Vaughan &co...

slt,

au niveau el84 , ne fait pas l'erreur des JJ, sovtek ou autres nullités grouve tube, il existe des anciennes mil specs reflector pas chères russes qui se rapprochent du grain Mullard/Valvo , prends les appairées!

au niveau pré, les productions actuelles de 12ax7 sont pas terribles, néanmoins si tu oublies sovtek, les 803s de jj sont pas mal, pour moi les tung sol sont les meilleurs, en v1 tu peux investir dans une silvania pour avoir le clinquant fender intacte
 
gromousse said:
Ok, so I will search new tubes. Do you have any advise for me on the tubes ?
My advice is not about the tone of the tubes but about reliability.

The DC3 and several other Mesa EL84 based amps are biased extremely hot. This means the tubes are being deliberately abused by the amp, and they will not typically last as long as they should under regular gigging use. It's how they get their EL84 amps to sound so good.

But the disadvantage is that not just any tubes will work well in these amps. The hot bias means that most lesser brands will red plate easily, which can burn out screen resistors and cause strange noises such as "snap, crackle, pop" that always leads to trouble. I went thru 3 or 4 sets of sovteks and GT's and Tung Sol's that would all red plate on me. I did find out that the Sovtek EL84M is supposedly a higher grade "military spec" version that can handle more voltage and more current, but I still had to go thru 2 sets before I found a quad of them that would not red plate.

The only tubes I have ever had in my Mesa EL84 amps that have not given me any problems were JJ's. The tone is not always ideal, but at least they can take the heat and withstand the abuse. I have never had a JJ tube red plate in my amp.

When you get your new tubes, put them in, then turn the amp on (power and standby on, so you can hear the guitar) and then just watch the tubes for several minutes. It will usually take a minute or two or three, but you can see with your own eyes if the tubes are going to red plate. I had mine turned on for at least 1 minute before the red plate would begin. When I got a set that I could watch for 5 minutes without any red plate happening, that's when I allowed myself to relax and start playing. Those tubes are still in it and it's working fine so far.
 
I never did find any documentation that tells how to change the bias circuit on these amps. It is usually just a matter of replacing the right resistors.

However, I just recently found a DC3 head for sale that has been nodded to have bias adjustment points and a pot installed on the back panel. It will be here in a couple of days. I am very curious to see how the mod is done, and how adjusting the bias affects the tones it spits out. If I can get a decent photo I'll post something for it.
 

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