The Friendly 12bar Blues Guitar Forum

Hi Guys
As you might remember is that I have a Ibanez Valbee combo 5W tube amp (that has been heavily modified internally).
In original it has a small cabinet with 6.5" speaker. But a with 12" speaker it sounds much better.
I had a 12" inch Bugera speaker laying around and an idea started to spread in my head.
Why not build a 12" speaker combo cabinet for the Valbee amp.
And here is the result :




The cabinet sides are made of 20mm thick pinewood, front and back of 10mm fiberboard and its covered with vinyl false leather.

Kalle

Very nice work!! I would love to see some pictures of the inside and maybe a sound clip? Did you have any problems matching the ohm resistance?

Yes. "fun" thing to do, I supose.
With youre know how it's no wonder that you know what you do.

Hope you upload a sound clip, if you have a mic.

Take care

Looks great Kalle, good job !
Not to the Demo sounds I'm missing here :)

Golfxzq wrote:Very nice work!! I would love to see some pictures of the inside and maybe a sound clip? Did you have any problems matching the ohm resistance?

The inside of the cabinet is painted black.
Matter of fact, i needed to install reinforcements in the top of the cabinet ( around the amp ) to reduce vibrations from the speaker going to the amp (tubes).
The original speaker was a 4 ohm, but the amp seems to like 8 ohm, as I have used a 8 ohm speaker in this amp for long.

Kalle

HalfBlindLefty wrote:Looks great Kalle, good job !
Not to the Demo sounds I'm missing here :)

Hi , I might do some recordings as got myself a second hand Zoom H4 (handy recorder).
The Valbee is a 2 tube amp ( one 12AX7 preamp tube and one 6L6 power tube in single ended Class A )
You can see the block diagram here

I have totally changed the "Boost" preamp part in the amp from the original "diod distorsion" to true tube distorsion.

/Kalle

Here are som sound samples:
Clean rythm guitar Stormy Monday (ala T-Bone Walker)
https://app.box.com/s/4fir1a9q1pq33epj6nz2
Distorted rythm guitar Layla (Cream)
https://app.box.com/s/682ti46lmabgrzja1tzh

Its my Yamaha electric guitar in both recordings and same amp settings, just pressed the "boost" button for distortion
Kalle

Cool... great sound. Those little Zoom recorders are amazing, they pick up every little detail with hardly any background interference. The amp sounds super, you have done well.

Kalle wrote:Its my Yamaha electric guitar in both recordings and same amp settings, just pressed the "boost" button for distortion

A big difference for a small button! As already said, well done!

Sounds good with that distortion. Fantastic litle thing you have modefied to suit youre needs. It's for youre needs, I guess ? The thing rocks.......

Nice job Kalle, it looks and sounds great!

Kalle wrote: I have totally changed the "Boost" preamp part in the amp from the original "diod distorsion" to true tube distorsion.

Did you add the tube and keep the diodes or did you definitively suppress the diodes ?

Hi
Here comes the technical stuff..
The first thing I did was to cut the diodes, that made a significant improvement.
Next step was to convert the boost stage from a cathode follower stage (driving the diodes) to a normal "overdriven" Triode gain stage.
The same time I added a potentiometer after the Triode gain stage, givin me a "post gain volume control".
This make it possible to have the same volume in Clean and in Boost(distorted) "channel" .
Then I modified the Power Amplifier with a bias current control potentiometer.

This has been my modify and learning project..

Kalle

Golfxzq wrote:Very nice work!! I would love to see some pictures of the inside and maybe a sound clip? Did you have any problems matching the ohm resistance?

Hi
I have updated the first post with better pictures including a picture of the inside
/Kalle

Hi,
Can I have a schematic of your mod. I also have a Valbee and I would like to do the same with it.
Thank you!

Maybe you should write a PN or visit him on soundclick, the last login is a while ago.