Liverpool Amp - Xtra Small Platform

[RJ Guitars]

I had a little idea for another Liverpool amp... I wanted to avoid the use of the pencil tubes but still keep this as small as possible. I plan to use 12AX7's for the preamp tubes and 7 pin EL95's for the power tubes. I had previously sorted out some component values that seem to work with this same tube set.

I had a bunch of smaller sized transformers leftover from previous bright ideas... I started with a half wave rectifier but I could only get 130 volts of unloaded B+. I decided to try to use with a full wave rectifier and managed to get an unloaded B+ of ~270 volts.

Look for updates as time allows...

[xtian]

Very cool. Where's the OT? Wait, I see they holes for it. How many watts output?

[Cantplay]

Want!

John

[Teleguy61]

Super cool thinking rj, waiting for updates.

[M Fowler]

Fun project rj.

[RJ Guitars]

Thanks guys - your encouragement is always a great motivator!

Very cool. Where's the OT? Wait, I see they holes for it. How many watts output?

I'll need to headphone to make sure the OT is in a good place... there isn't much real estate so I already wish I had pushed the output tubes toward the back a little more.

How many watts? That would require I do the math... hold your breath but I'll guess 6 or 8 watts in the meantime. From my previous experience with this tube compliment I expect it will still be too loud for the living room

[RJ Guitars]

I ran the headphone trick and found a decent spot for the OT... although there really wasn't any place on the chassis that was dead quiet. I'm not sure if that's because the PT is open frame or the fact that there just isn't much real estate to work with there. It didn't seem to matter what angle I tried, distance made the most difference. This OT is a replacement for a Fender Pro Junior.

I have the PS filtering caps ready to mount up next... stay tuned.

[RJ Guitars]

I did a little more soldering tonight... if I did things correctly the power supply is all done. I'll do a few measurements and then I plan to wire up the pots next.

I'm borrowing a page from Zippy's play book and putting the pots and bright switch on the outside of the chassis... puts it all in plain sight. After it's all wired up I'll place the entire pre-wired assembly in the chassis. Never tried it before but it looks like it's simple enough??

[xtian]

Hey! Cool trick. Just remember which way is up for the switch!

[Thomas_H]

Nice build!
love this little builds! Keep us updated!

[gktamps]

I'm borrowing a page from Zippy's play book and putting the pots and bright switch on the outside of the chassis...

I do the same thing, RJ. It's particularly handy for wiring up the bright switch, especially if like me, you rotate the volume pot terminals to face the switch (or mini-pot, as I've been using).

[RJ Guitars]

Nice build!
love this little builds! Keep us updated!

Thank you and welcome to the TAG forum! We don't have too many builders here from South America... the folks here are muito bom!

I'm borrowing a page from Zippy's play book and putting the pots and bright switch on the outside of the chassis...

I do the same thing, RJ. It's particularly handy for wiring up the bright switch, especially if like me, you rotate the volume pot terminals to face the switch (or mini-pot, as I've been using).

Yes, I have rotated the volume pot around on some builds and it's especially helpful when dealing with two bright caps and all that extra antenna wire. In this case I am only going to have one bright setting so I'm not sure how I'll do it.

I am curious if anyone has a good suggestion for very small control knobs. With these tiny little pots there isn't much room... probably need something 3/8" diameter.

[Thomas_H]

Thank you and welcome to the TAG forum! We don't have too many builders here from South America... the folks here are muito bom!

Thanks! I've been reading a lot of stuff here, the smaller builds of famous circuits are amazing.

As for the knobs, I use davies 1900h knobs for my 1590a builds, tayda sells them:
http://www.taydaelectronics.com/hardwar ... black.html


I made a superfly with them:
[img768]http://i1303.photobucket.com/albums/ag1 ... 1f93e7.jpg[/img]

I used 9mm pots in this build, but the 16mm pots fit side by side with this knobs without issues.

[RJ Guitars]

Yes, those are exactly what I need, thanks! What tubes are you using in your super fly? that is definitely a compact unit. I thought the 16mm pots were really tiny, I'm not sure I could see well enough to try 9mm. Also wondering what you used for an output tranny, I assume the big tranny I see is the power tranny?

[Zippy]

Yes, those are exactly what I need, thanks! What tubes are you using in your super fly? that is definitely a compact unit. I thought the 16mm pots were really tiny, I'm not sure I could see well enough to try 9mm. Also wondering what you used for an output tranny, I assume the big tranny I see is the power tranny?

Nyet. The trannie is the output. It uses an external power supply.

http://www.frequencycentral.co.uk/?page_id=11

http://www.freestompboxes.org/viewtopic ... 8&start=40