Finished my first Preamp. The 3 channel LondonPower pre-amp

[SonicSonar]

Hi all.

I completed phase 1 of my amp build process.  And it's about time.
Thanks to Kevin O'Connor, LooseChange (Dan) , and my brother ( Phd. EE) who all helped in getting this project done.
There is more work to be done, for example foot switch, button #4, front face plate, effects loop....
But, those are not needed at the moment, and I can play around with what I have now.


All green boards were bought from LondonPower.  The yellow ones were made by me.  As you can see, there are strips of yellow fiberglass board with wires connected.  This made my life easier making changes and moving things around.  Sometimes you need 3 wires in one spot.  I found that just about impossible to do on the circuit board.  I got the idea to do this from my modification days working on Fender silver and black face amps.

In the upper left of picture is an empty tube slot.  That is my effect loop circuit (http://www.londonpower.com/catalog/product_info.php?cPath=21&products_id=24).  Since I am not a pedal type player, I have no need for it.
The audio signal bypasses and goes to the line out.  Someday in the future I will add it to the circuit.

Directly in the middle, is a led on the yellow board.  Right next to the PSU.  That is my channel #4.  I have not decided what I want for it.
Currently I have 3 channels.  The clean 2 gain stage, marshall 3 gain stage, and the Solano 4 gain stage.
Maybe I can mix the clean with the Solano for the 4th.  

Middle left is the switching circuit.  I created another fiberglass board right next to it, so I modify the switching as I play around with it until I find the combination that works for me.  That is much easier than working with the circuit board.

Here is a closer pic of the switching QRK board. (http://www.londonpower.com/catalog/product_info.php?cPath=20&products_id=16)


This build has been a learning process.  2 steps forward, 1 step back.  No sooner than after finishing the switching board did I realize, the JFets would be better placed next to the audio signal.  Not the other way around.   ugh.

Putting in the LEDs were another pain.  Chassis work in general was difficult.  I would really like someone to make me a nice clean looking faceplate for this instead of the ugly thing I have now.  


As bad as that thing looks, it is quite functional and void of unwanted noise.

I did my best to build this thing similar to the GT Trio.

The pre-amp is in working condition, I will use it now and see what happens 6 months of use.  So far I really dig the tones I get out of this.  The Z-PRE is my favorite. http://www.londonpower.com/catalog/product_info.php?cPath=15&products_id=60.
Originally I had 2 12AX7s in there, but that was way too much.  Brought it down a notch to 2 12AT7s.


The next project I am going to do is the LondonPower Power amplifier.  Plan is to finish that by end of next year.

One last thing.  If you have any questions, please ask.

Thanks

[jjasilli]

 

[plexi50]

Thats quiet a feat! A lot of work. I get lost if it isnt on a turret board

[LooseChange]

Nice job and it all works!!  Man, you really struggled for a while. :-)
I don't think the chassis looks too bad. I like the 1-4 push button channel selector!!

[John]

That looks like a LOT of work! Thanks for sharing!