15 watt Liverpool Combo Build

riscado · Post by **riscado** » Wed Sep 12, 2007 4:37 pm

Hey happy birthday man... and congrats on your grandaughter!

UR12 · Post by **UR12** » Mon Sep 17, 2007 4:50 pm

Hey guys thanks for the congrats!! I had another weekend that I didn't get to spend much time on the amp. I finished all of the heaters and can now flip the power switch and see the tubes glow. Woohoo!!! I did get to spend some time working with some mosfet switches to replace the relays in my 2 channel TW inspired amp. Richie also brought me over two 300B50 Sammi 12" speakers to go in the combo cab and I got those mounted and ready to go so the cab is complete. To many irons in the fire

.

UR12 · Post by **UR12** » Mon Sep 24, 2007 4:38 pm

I finished up the power supply wiring last night and tested the voltages with no load on the power supply. I'm getting about 350v B+ at the plates of the power tubes with no load. I figure this will drop down to about 320v or less once I get the tubes hooked up. The variable voltage regulator is working great and I can dial down the B+ to anything I want. This is the improved design with Paul Ruby's current limiting mod. (Thanks Paul !!...You da man

) I'm still using only 6 parts to do the VVR board, just one wiring change on the board and two component values changed.

UR12 · Post by **UR12** » Wed Sep 26, 2007 4:22 pm

Few more pics from last night. The DC part of the PS is done along with all of the board to tube socket wiring. I hope to get started on the controls tonight.

riscado · Post by **riscado** » Wed Sep 26, 2007 6:02 pm

looking seriously good...

thanks for sharing

zendragon63 · Post by **zendragon63** » Tue Oct 23, 2007 4:57 am

Hi Dana, been kinda keeping an eye on the 15 watt build--hope it is going well and I am excited to see what you end up with. I just finished a 2XEL84 Liverpool copy; it is a Ceriatone preamp board into a Marshall 18 watt chassis with a tube rectifier and a 'wreck PS. Ceriatone OT. Voltages all worked out pretty well. Had a few layout issues but finally got them cleared up. And, while it sounds and plays pretty good (as compared to the YouTube sounds), it does have a very subtle lack of lower end that I can hear in the Liverpool sound clips. I did change the 68K/.0022 to a 150K/.0047. Maybe it's the speaker (1X12 Greenback) and maybe not. What I wanted to ask is why you are chosing to use a 10.2 K OT rather than a 8K that is standard for two EL84s. Is there a reflective load thing going on? And is a Heyboar a fuller frequency spectrum OT? Appreciate your input and hope it may be of interest to others pondering a similar build.

Richie · Post by **Richie** » Sat Nov 10, 2007 4:25 am

I got to play this amp tonight. Very nice, put a smile on my face after the first few notes.. oh yeah.. Its going to be bounted into an 2x12 18 cab.
I know some had said they have trouble with combos, i don't think it will be a problem. Many TMB 18 watters,and a Trex 18 were built in a marshall style chassis,and they turned out fine.

dartanion · Post by **dartanion** » Sat Nov 10, 2007 7:59 am

Pics? Where? I'm dieing to see this baby!!!

UR12 · Post by **UR12** » Sat Nov 10, 2007 1:56 pm

Here are a couple of pics of the amp. I haven't got the Sammi speakers wired up yet in the combo cab. Richie played it through a 4x12 and a 4x10 cab last night and it sounded very good even with the crappy test tubes in there. I'll be tweeking the amp a little and going through changing out the tubes until I find the ones I like. I really want to get some clips of this amp and will post them here when we get them done.

This thing has plenty of gain on tap and I don't believe all of the BS that you can't put a TW in a combo. ( https://tubeamparchive.com/viewtopic.php?t=3790 ) I think Ken just didn't like combos and there should be nothing keeping someone from building a lower powered TW amp in a combo. There are plenty of companies building high gain amps in combos with great success.

The 10.5k tranny sounds great. I figured that if the original Liverpool was running 5.2 with 4 tubes then I would double the imp for 2 tubes and this worked out well. It has the sustain and the Liverpool sound and tactile response (Just like my Ginger clone with the 1/2w switch activated).

This is going to be my last TW project for a while. I don't have any plans of building anymore in the near future. I'll be checking in now and then but I'll be moving on to some new designs of my own that I want to work on.

El_Martin · Post by **El_Martin** » Sat Nov 10, 2007 2:19 pm

Nice work, Dana!

About TW combos: you are right, lots of combos out there with even more gain on tap...

My own 15 W Liverpool is about to be fired the first time.
Wish me luck, it's my first higain build...

What kind of amps are you now into if I dare ask?
I'm not sure, if my next amp will be a Dumble lite or some sort of ultra low power amp. (12AT7)

Ciao
Martin

UR12 · Post by **UR12** » Sat Nov 10, 2007 2:51 pm

El_Martin wrote:Nice work, Dana!

About TW combos: you are right, lots of combos out there with even more gain on tap...

My own 15 W Liverpool is about to be fired the first time.
Wish me luck, it's my first higain build...

What kind of amps are you now into if I dare ask?
I'm not sure, if my next amp will be a Dumble lite or some sort of ultra low power amp. (12AT7)

Ciao
Martin

Hi Martin

Yes, the very best of luck to you on your first hi gain build. Amp building really is great fun and one of the biggest parts of that fun is firing the amp up for the first time.

I'll be playing with some Solid State Relays that Mhuss turned me onto and I have a couple of amps designed on paper that I want to build. They are'nt anything that special just something that I have never done before. I want to try some different combinations of SE and PP amps with different tubes and some things like that. Definately nothing that is going to revolutionize the tube amp industry or have a bunch of bogus LEDs on the front panel

Here is the first tube I will be playing with

It's a dual pentode power tube. You can run 50w from one tube in PP.

Tubetwang · Post by **Tubetwang** » Sat Nov 10, 2007 4:12 pm

i really like the neat and clean layout Dana.

This is something i strive for...

mlp-mx6 · Post by **mlp-mx6** » Sat Nov 10, 2007 4:30 pm

UR12 wrote:I'll be checking in now and then but I'll be moving on to some new designs of my own that I want to work on.

I hope you'll keep us in the loop as your designs progress. Who knows, perhaps you'll inspire yet another category besides Wreck and Dumble here on the Amp Garage!

skyboltone · Post by **skyboltone** » Sat Nov 10, 2007 5:06 pm

What's the TO-220 sand state for? You playing with this too? I got some Iron that's just a bit high for what I'm doing. The darlington transistor here is an obsolete NTE unit that's good for about 600V. It's a 150W. Sure cheaper than a 50W stud mount unobtainium zener diode.
[IMG:497:280]http://i15.tinypic.com/7xl4iud.jpg[/img]

UR12 · Post by **UR12** » Sat Nov 10, 2007 5:56 pm

It's a TO3p case power mosfet used for the variable voltage regulator. 900v 150w 8a. I use it to vary the B+ to the amp.

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15 watt Liverpool Combo Build

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