Help with Dual Caliber

[Lupo]

Hi, I bought from Ebay a Mesa Dual Caliber, but I found some oddities on the paint of the graphic equalizer: there are strange bubbles: I can't say if they are bubbles of rust or paint errors (I touched them with my nail and the bubbles are very hard and seems to be of paint), Have you ever see this strange thing on other dual calibers? as well as a strange oxidation of the speaker (It can affect the sound?).
Furthermore V1 V2 V3 are Mesas, V4 V5 V6 are Sovteks: how this can affect the sound?
For example using the rhythm channel at 1 of gain the sound is already crunchy.... if I use the pot with pull mode the sound is very distorted.
I'm attaching the photos and thank you in advance for your help and answers!
I apologize for my uncorrect and basic english.

 

[Lupo]

I apologize for my concern, could someone give me any other advice?
Is it normal to feel vibrations on the wood of cabinet playing at low volume levels: output level 7 and master at 2 on lead channel?
I apologize for my english, thank you in advance.

 

[GuitarBear]

Hello - don't worry about your English... it's just fine.

I am not sure about the paint bubbles around the graphic EQ. I have not seen that before, but it could just be a flaw in the painting - a drip perhaps. Maybe someone else will post with more knowledge than I have.

Regarding the tubes, there is no problem mixing preamp tube manufacturers. My DC-5 has a tube "cocktail" from several different manufacturers (thanks Edward!). As long as the tubes aren't bad you don't have to change them. You might want to experiment with different preamp tube combinations to see what you like best. You could also try different tube values (12AY7, etc) if you want less gain than a 12AX7. This might be what you are looking for if you want to reduce the gain/crunch somewhat. Search for some prior posts about tubes for your Dual Caliber. There is a lot of information here - just keep looking and you will find what you need.

 

[Lupo]

thank for your help!! May I ask you if your wooden combo chassis rattle too at garage volumes for example output at 7 and master at 2?? Thank you in advance!

 

[daviedog]

I have had TUBE rattle that I confused with the cab vibration.
Try to run through a separate cab. If there's no vibration, you have isolated your problem.
For high volume, pull chassis & gasket entirely. Wood & metal vibrate at different frequencies. And by all means, buy new tubes. You'll need down the line anyway..

 

[Lupo]

Thank you very much for your suggestions!
I put new power tubes Mesa STR 440 yellow (the old ones were Mesa STR 420 grey) and the rattle disappeared!
I tried to run my DC5 thru a custom 2x12 cab with FANE Sovereign speakers and there are no vibrations... and the DC roars!!!
Thank you!!

 

[MichaelC4]

I put new power tubes Mesa STR 440 yellow (the old ones were Mesa STR 420 grey) and the rattle disappeared!

Good to hear that.