• From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Topic: 12AU7 in V1 to lower gain

Hey all,

I just had some extra $ching$ laying around, and I though it'd be a good time to play with preamp tubes! So much fun, and safe!  cool

In the past:
I had 12AX7 Groove tubes, and didn't like them
I've had ECC83 JJ preamp tubes, and thought they were too high gain
my preamp setup before yesterday had two NOS 12AX7's and three JJ's...SO

I decided to try something more low gain. I bought an Electro Hamonix 12AU7 for V1 (which colors sound most) and a EH 12AT7 for V2. The final three preamp tubes I bought Mullard 12AX7.

The tubes are going into my Rivera Knucklehead 100 watt. Before, with JJ preamp tubes and the gain kicked in, having the gain (volume) on 4 or 5 was almost too heavy. With my "low gain setup," I noticed a difference. With the vol gain set to 4 it's really dirty blues, and on 5 it's rock... so there's  a sweet spot. Cranking up the gain gives you hard rock and metal combinations yet. I might try the 12AT7 in V1 next, we will see.

One thing i heard is that V1 should be your quietest tube when you tap on it, and this 12AU7 is the loudest. I haven't had any problems in the way of feedback or anything yet, so we will see. Plus I'd like to play with different combinations more.


It's really fun now that I've been playing Rivera amps for like 12 years, I can really start to notice subtle differences. This difference was pretty huge though.

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool
  • From: North Carolina
  • Registered: 2008-10-26
  • Posts: 2,926

Re: 12AU7 in V1 to lower gain

I bet the differences are huge!  I hope its what you were looking for, besides its like you said if you wanted gain you got that other Rivera thats lower wattage.

AD3THREE's Website

  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: 12AU7 in V1 to lower gain

AD3THREE wrote:

I bet the differences are huge!  I hope its what you were looking for, besides its like you said if you wanted gain you got that other Rivera thats lower wattage.

Traded it for this Knucklehead straight up.  cool

I do have a modded Blues Jr though for lower wattage stuff.

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool
  • Nairbr
  • Nairbr
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  • From: Perth, Western Australia
  • Registered: 2009-10-25
  • Posts: 53

Re: 12AU7 in V1 to lower gain

Hi
Another important tube for your sound is the Phase Inverter, I like using a Sovtek 12AX7LPS (Long Plate Spiral) they are warm sounding and remove any harshness in your gain signal.

GUITARS - Les Paul R9 VOS Cherryburst, Les Paul Traditional, Fender Rory Gallagher Tribute Strat, Fender CS 40th Anniversary Strat.
AMPS - Ceriatone 50w ODS HRM, Ceriatone 30w Stray Cat
EFFECTS - TC Electronics GMajor, T Rex Spin Doctor, Univibe
  • Registered: 2009-02-24
  • Posts: 197

Re: 12AU7 in V1 to lower gain

I've done alot of tube swapping in my years.  These are just my experiences:

12AU7 will have good tone, but probably lower the gain WAY too much to be useful.
12AT7s are bright/thin. Not bad for reverb drivers or phase inverters, but I've never heard one sound good in V1 or V2.
12AY7 has more gain than 12AU7, might work, but never did for me.

For me, the magic tube in V1 (or V2) if you want to lower the gain a bit but retain the great tube tone is a 5751. However, it really must be an NOS 5751...  you can get the JAN Phillips or GE 5751 relatively cheap I think. New production 5751s just don't cut it. Also a good one for the reverb driver or phase inverter.

  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: 12AU7 in V1 to lower gain

I had some NOS tubes in V1 and V2.... decided to change them out.
I did buy a 12AT7 and it's in V2 next to my 12AU7...

The more I'm playing it, the cleans are really good, and the gain is just dialed back a bit from the regular 12AX7's, noticeably dialed back. I will like this for a time, best part is that it's easily reversible!

The phase inverter is always the last tube, right? So V5 in my case?

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool
  • Registered: 2010-02-01
  • Posts: 175

Re: 12AU7 in V1 to lower gain

ruger9 wrote:

For me, the magic tube in V1 (or V2) if you want to lower the gain a bit but retain the great tube tone is a 5751. However, it really must be an NOS 5751...  you can get the JAN Phillips or GE 5751 relatively cheap I think. New production 5751s just don't cut it. Also a good one for the reverb driver or phase inverter.

+1

The 12au7 in V1 made my Trainwreck clone too tame but a 5751 in V1, 12au7 in V2 and 12AT7 in PI works a treat :-)

  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: 12AU7 in V1 to lower gain

Sweet!

I will try this after this weekend!

V1 - NOS
V2 - 12AU7
V3 - Mullard 12AX7
V4 - Mullard 12AX7
V5 - 12AT7

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool