London Power Standard - finished pic and soundclip

[stephenl]

more pics

[stephenl]

A few more comments:

I didn't use a single run of shielded cable in this thing and it's super quiet.

The separate tone stacks, UL/Pentode, Cathode/Fixed really give an impressive tone palette.

[stephenl]

I know this project veers far from the norm here - using a PCB... All my other builds have been turret, eyelet, and I even did a PTP. It would be cool to see other build it. I initially considered scratch building it like Ian but I'm very happy with the results.

Even if I were to try a scratch build of this, I would probably use KOC's Power Supply Board and Tranny's - good stuff.

The only thing that I'm not sure I love(very little concern though) is the PCB mounted tube sockets... The boards are rigid, well made, and well supported. There's no visible flexing when inserting/removing tubes. The pins are all bent over and well soldered.

[V2]

Looks great. That's a big OT!

I see the bias jacks, and I assume the bias adjustment pots are located behind the octal tube sockets, toward the rear panel of the amp. How will you access the jacks and pots when/if the chassis is loaded into a cab?

[stephenl]

Yes, the bias pots are close to the power tubes - they are integral to the PA board. You could also mount them remotely.

Access to the bias pots and test points maybe isn't ideal for some. I considered other placement options and decided I was ok with it as I don't tend to roll power tubes much - I really like JJ KT66's. I might try some TungSol 5881's - I like them too. You can use any of the common octals.

I may choose to make the front valence on the head cabinet removeable so that you wouldn't have to remove the chassis to bias...I haven't get that far.

[stephenl]

Here is a short clip of me noodling. Guitar straight into amp and speaker - no effects. Miked with Audix i5 into usb interface into ipad2 w/Garage Band...some latency issues(pops and cutout)and clipping. No eq. Tiny bit of reverb added in GB.

https://soundcloud.com/stephen-littlefi ... ndard-clip

[V2]

sounds great!

[stephenl]

Thanks V2. I really like the amp a lot.

Other than a few personal preference tweaks, I really didn't veer from KOC's design.

I'm a total noob at recording - that was my first attempt

[stephenl]

V2, how did yours turn out? Did you resolve the noise issues?

[MakerDP]

Just found this post....

Nice job on the LP Standard! I've been kicking around doing one of these since i bought Tonnes of Tone in the 1990's. I even bought a kit from Kevin back then (no pcb's then) and since I had NO IDEA what I was doing, it was a total disaster! Now that I have a clue about the right way to build an amp, I'm sure it would be just fine to do one now.

Sound clips are SO RARE of this amp so thanks for posting those. It sounds great!

[stephenl]

Thank you. The clip doesn't really do it justice but gives you a basic idea.

I'm starting another one. A fifty-watt this time with built in effects loop and reverb.

I'm going to try something a little different in the power section. I was intrigued by this hifi design I saw over on DIYAudio.

I had Heyboer build up the interstage transformer for me. I have no idea how it will sound ... But hopefully the best of SE and P-P in one amp.

[V2]

V2, how did yours turn out? Did you resolve the noise issues?

apologies for the delay. the noise was due to a bad pot (master, if I recall). The amp turned out pretty good. I'd like to try a 25 watt variant, though....

[MakerDP]

The clips aren't perfect but they get the point across nicely.

I've been wanting to try a Dumble build but I am short on the cash to start a new project from scratch so I actually bought his D-Pre kit today. I'm going to try it in my "experiment chassis" that i use for trying out stand-alone preamp designs. If I like what I hear I will cannibalize a couple of other builds I don't really use anymore for parts and build a full-blown amp out of it.

[stephenl]

V2 - After rolling a bunch of tubes through the preamp, I found that a JJ 12AX7MG for V1 and JJECC803 for V2 sounded best to me. I tried some Mullard and TungSols as well but didn't like them as much. Did you use the LTPI from TUT5? The latest version uses a gain stage + Cathodyne PI - I used a 12AU7 w/ appropriate plate/cathode resistor changes. I used .022 coupling caps throughout. Since I didn't include the effects loop or reverb, I added attenuation between V2 and the GS/CathodynePI.

Maker - I look forward to hearing how the D-Pre turns out.

[gingertube]

Steve,
Will be interested to here how that power section above works out.
Would not be surprised if it gives a fair amount of SE sound. The output section with Ultralinear with cathode feedback will be very clean so with a bit of luck what will come thru' is the EL34 driving the interstage/phase split tranny.

If you have an interest in slightly different power amp designs here is my HiFi design. I've been itching to try it as a git amp too.
http://www.diyaudio.com/forums/tubes-va ... -huey.html

Cheers,
Ian