DC-5 preamp valves placement onboard?

[bissoboa]

Hello, I am new!

I can't find anywhere in internet which is the relative position of the pre-amp valves named V1, V2, V3, V4, V5 and V6 in the DC-5, looking its board from the top.
I noticed that V1 is the nearest to the input jack, but the others? are them in order from left to right?

thank you very much!
Stefano

 

[MrMarkIII]

You are correct, sir!
V1 is closest to the input jack, V6 the furthest from.

 

[bissoboa]

OK thank you! :wink:
though reasonable, I wasn't sure of this only by looking over the PCB and schematic

Stefano

 

[evilpresence]

I called Mesa and left a voicemail asking them about the positions. They called me back the same day and left me a voicemail saying that the DC-5 was the only amp to his knowledge that they didn't include the schematic in the user manual. He said if you look at the DC-10 user manual, it's identical minus the two extra 6L6 slots.

http://www.mesaboogie.com/manuals/Dual%20Cal%20DC-10.pdf

page 11 is your friend

 

[ErickG]

After reading this post had me puzzled... On my DC-5A there is a Schematic sticker, very similar to the one that is in the DC-10 manual, showing the tube layout. On this sticker it shows V1 being on the opposite side with V6 being closest to the input jack. After reading this post is there a difference between the DC-5A and the DC-5B where the preamp tubes are in opposite directions from the input jack?

Amp sounds good... But has me worried that may be I have the wrong sticker on it somehow? Everything on the sticker is in the right location except for the reverb connections, on the sticker they are on the right side of the power tubes but in reality they are on the left side. This is from looking at the back of the amp.

If anyone knows this about this would be great.

To confirm it's a 5A, it has the plastic rocket switches, the EQ/Reverb input jack is in the back and it has the ground switch as well.

Like I said any information would be great. I can see if Mesa expected people to only run 12AX7s it wouldn't matter, but if I wanted to change out the High Gain Channel tubes for something unique for each one I need to know if the sticker on it is correct or not.

Thanks,
Erick

 

[bissoboa]

Very interesting... Thank you very much for the support! I didn't know the DC-5 manual was missing this schema.
Now, it seems to agree with my initial statement: valves arranged from left to right looking upside the board in front of the amp.
Moreover mine has got the stick on the back not filled, so it can't be wrong :mrgreen:

 

[kekam35]

V1 is always closest to input jack.

 

[ErickG]

Here is a pic of the schematic sticker inside the cabinet. Mine looks similar to bissoboa's, but mine is filled out. I changed a few tubes based on this schematic. If it's true that V1 is always closest to the input jack them for me I have V1 and V6 backwards and need to change them with each other. The amp does sound good with it the way it is, but if I were to change V2 now I would see some other interesting effects I am sure. I put a 12AT7 in V6, at least what I thought was V6, and a SPAX7 in V1, again what I thought was V1.

Looking at bissoboa's picture again mine is flipped with respect to the Power Tubes.

What would you guys say it is? I am thinking the schematic inside my amp is incorrect. ???

Thanks,
Erick

 

[MrMarkIII]

The "flipping" is not occurring left to right, but between looking DOWN on the chassis and looking UP at it from below. V6 is closest to the white and gray reverb cables in both.
Except for the Express, V1 is always closest to the input jack.
The real difference between
"A" and "B" versions are the red and green LEDs next to the channel Gain controls, indicating the channel selected.
"A" versions have them, "B" versions don't.

 

[ErickG]

Okay, took me a little bit here to think through what MrMarkIII is saying; about the looking down and versus up on the chassis. In the schematic sticker on my amp and the DC-10 schematic the V6 slot of always closest to the reverb connectors. So, in my case I have the V1 and V6 tubes in the wrong spots. I will have to correct this and hear what happens. :shock:

Thanks,
Erick

 

[billboogie]

V5 is the reverb tube. Pull V5 tube going left to right and check your reverb, then check the other way and you should have your answer. I believe V1 is nearest input.