Other Amps

New amp build

1

Starting a new amp build. Cab is the usual dovetailed pine box and birch baffle.

2

The circuit is a Marshall 1974x with a few twists. There is a standard Marshall channel with full tone stack and Master Volume, and the second channel is Vox voiced with an EF86 preamp.

Also running higher voltages than usual with a pair of 6GK6 power tubes for the output.

4

Looking good PD. Do you have a jig / fixture for your dovetails?

Nice clean boards you've got there.

5

Yea, I use a Porter Cable jig. I go thru stacks of lumber and pick out the knot free sticks.

8

I hope it sounds as good as it looks! Circuit description sounds yummy. Thank you for sharing your builds. Building and fixing threads are great.

9

Chassis progress. I’m using a Hammond power transformer out of an AO-43 monoblock. A little higher B+ than usual for this circuit. The output transformer is from a 6L6 powered amp, good for about 30 watts. Run it 8K:8 ohms, should sound huge.

10

I’ve decided not to use the 6GK6 power tubes. Different pinout than an EL84. Someone down the road might try sticking a pair of EL84’s in and cause some sparks to fly.

Instead I’m using a pair of 7189’s. Same pinout and parameters as the EL84, just able to take more voltage.

And yes, the controls do go to 11.

11

Great looks! Is that a silk screened control panel?

12

Nope. Two layer material cut with a laser. Very trick. Done for me by a friend. Wish I had those skills.

13

For those interested, running the smallish 4K:4 ohm OT at 8K:8 ohm for EL84’s, that was BZ’s idea.

Thanks man.

14

Nope. Two layer material cut with a laser. Very trick. Done for me by a friend. Wish I had those skills.

– Powdog

Me too!

15

Love the chicken heads and the fact that it goes to 11.

16

Can't you get you can get more juice out of 7189 than you can out of an EL84? I'm using pairs of the Russian equivalent (6p14p-ev) in my stereo amp. Sherwood used them in hifis at 10 watts a pop.

Very cool build! Maybe somedayI'll make a dovetailed pine cabinet for fun. For me it would be mostly for weight. Are you putting tolex on it. Does it end up being significantly lighter than a 1/2" baltic birch cab (generally what I use) Good call of Billy Zoom's. It's like when you try 6L6s in a deluxe build and have to use a 4 ohm speaker as a result of the different load resistance of the 6L6 . Those Hammond PTs are skookum!

17

Oh boy! I can’t wait to see this one take shape!

18

With a 5U4 rectifier, I expect to see around 350v on the 7189 plates. 20 watts sounds about right.

Laurens Hammond ran 6BQ5’s at those voltages. All of the tubes I’ve pulled out of Hammonds have been European made (England, Holland, W.Germany). Tough tubes.

19

Russian 6P14P tubes would handle those voltages with the same pin out

20

Bet it's going to sound killer.

21

I have about 450 volts on my 6p14p-Evs...hee hee ..BOOM! biased to 10 watts per pair.

22

I worked on a Traynor Guitar Mate last week with EL84s and 425 volts on the plates.

23

Dang you have the coolest looking panels on these amps

24

The cabinet kinda looks familiar. More pics!

25

This is what I’m shooting for.


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