DC-3 Reverb question!

[zoolguitar]

Hi guys, I wonder if you could help me.

My DC-3 's reverb has ceased to work. When I turn up the reverb on both channels all it does is create awful noise. I changed the output valves only 6 months ago and haven't played it a huge amount.

Is this a common problem that can be easily fixed or could it be down to one of many things? Any help would be much appreciated. Thanks!

 

[bendo]

The first step is to replace with a KNOWN GOOD tube. Is is the V5 tube. Tubes can fail within 6 months. That is why Mesa's pre-amp tube warranty is exactly 6 months. :mrgreen:

Also, make sure the RCA cables are hooked up properly, as that will cause feedback as well.

 

[zoolguitar]

Hi there, thanks for the reply
It's been going on for longer than 6 months. Could the other set of valves have anything to do with it? I haven't changed those in a long time!

 

[bendo]

It's possible, that the oscillation of the signal from the reverb is causing another tube in the pre-amp to go micro-phonic.

If it hasn't been serviced in a while, and FULL set of pre-amp tubes 6 (power tubes also 4) is strongly recommended.

Check Doug's tubes, Tube-Depot, or The Tube Store, Google will direct you in the right direction. The only EL84 power tubes I can get any extended life out of with good tone is the JJs. I've tried, Sovtek EL84s and the Military version, Mullard's, and, Stock Mesa (Sovtek). I wouldn't even consider putting NOS tubes in for fear of them being eaten alive and wasting a bunch of $$$.

For Pre-Amp tubes I run:

V1 - EH 12AX7 or a Tung-Sol depends on what I have on hand
V2 - JJ 12AX7
V3 - Mullard re-issue 12AX7 - This gives a nice rounded tone to the JJs modern sound.
V4 - JAN Phillips 12AT7 Black Plate - More headroom on clean channel. Sounds really silky and full with a nice breakup
V5 - JAN Phillips 12AT7 Black Plate - Same reason as above
V6 - JJ - These last the best here and sound good

You could take it to a tech, but replacing tubes is like replacing light bulbs. Hope this helps, and good luck!

 

[zoolguitar]

Ah ha! So it's not the pre amp tubes I changed it's the other set. I haven't changed the preamp ones in years! This makes more sense.

So you say to change V5? It says V6 is a reverb tube too. Would it be more likely to be V5?
Basically the least amount of tubes I have to buy the better

Thanks for the info buddy!

 

[bendo]

V5 is the reverb driver for the Dual Caliber Pre-amps. V6 is the Phase Splitter/Driver. The DC5 manual does not have a tube map so.... But, the tube maps in the DC-3 and DC-10 manual are the same so...

However, replace them all. All 6 of them. Find one of the pre-amp kits that Doug's tubes or one of the other vendors sells.

Whatever you do, MAKE SURE you use a Tung-Sol or an ElectroHarmonix 12AX7 in V1. You can use whatever 12AX7 you want, but these sound the best.

 

[soundchaser59]

What does it do if you unplug the reverb? If you have the reverb either turned off or disconnected then the amp sounds great?

Reverb tanks are cheap, a lot cheaper than a full set of tubes. Maybe you should try replacing the reverb tank instead? I know any tube can fail at any time, but good preamp tubes tend to last a LOT longer than 6 months. I'm skeptical...... :shock: