Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ratgon on April 24, 2017, 07:49:09 pm

Title: Finished PR build and Sluckey's AC-15 questions
Post by: ratgon on April 24, 2017, 07:49:09 pm

Hi all! I checked in a couple weeks ago after a bit of a hiatus but I've managed to finally finish a couple projects I'd been working on. Most recently, I've finished this Princeton Reverb from Doug's parts and Sluckey's info. I had trouble with the trem originally but finally sorted it out. I also spent a lot of time working on the cabinet. I personally shy away from having the amps look like the classic amps they're buiult on, because, well they aren't. I just really like designing the cabinets almost as much as I like the amp building.

Anyway, I'm really happy with the amp and it's sparked a lot of interest in my music circle asking if I could " build one for me!" I've never really considered building these things to sell and I'm not really now. But, if someone is willing to buy all the parts and let me build it for them then jeez! That's like winning the lottery.

So, one friend, who's likely the most serious about actually doing this wants me to build him an AC-15. I hadn't really had much experience with this amp in the past so I've been doing a lot of research on it. Of course, all roads lead back to Sluckey and Hoffman! I'm really hoping I can get a chance to take on this project.

This is by far an epically more complex amp than I've made so far. I'm still very new to this but I'll just have to be very patient and diligent with my work. I've gone back to school and that'll regulate how slow I go with this anyway. Built in patience!

So, I'll be asking for help and encouragement along the way. As I write this I'm watching Pompeisneaks's (sp?) videos on his AC-30 build. It's amazing how all roads truly do lead back to here.

First question for Sluckey is what are the dimensions of the chassis you used? I guess turretboards.com is no longer so I'd like one that seemed to be relatively roomy like yours.

Also, I'd like to build in the mods you speak of so I guess I'm asking if they are a fairly straight ahead addition to the original layout.

LAstly, I notice that Doug's parts list for the AC-15 (which I'll be using) doesn't include an EF86. Is the 12au7 listed a replacement for that?

Anyway, thank all of you for all the past and future help. I'm grateful to have a community to help in this obsession as I start from the beginning.

Title: Re: Finished PR build and Sluckey's AC-15 questions
Post by: sluckey on April 24, 2017, 08:04:55 pm

Quote

First question for Sluckey is what are the dimensions of the chassis you used?

Chassis size is listed in my pdf document on my website.

All mods are straightforward and easy.

12AU7 is ***NOT*** a replacement for an EF86.

Title: Re: Finished PR build and Sluckey's AC-15 questions
Post by: ratgon on April 24, 2017, 10:42:43 pm

Thanks Sluckey. I really appreciate it!

I'll keep you posted.

Title: Re: Finished PR build and Sluckey's AC-15 questions
Post by: terminalgs on April 25, 2017, 08:04:22 am

Cool looking amp.  Is that contact paper?

Quote from: sluckey on April 24, 2017, 08:04:55 pm

12AU7 is ***NOT*** a replacement for an EF86.

new EF86's are $20, NOS czech units are $35 with a few clicks of a button.  If you need to tighten the belt on the BOM expense list, I'd do it somewhere else.  Especially when you consider the amount of time it takes to build an amp, the first preamp tube should be primo (be it a EF86, a 12AX7, or anything..)

Title: Re: Finished PR build and Sluckey's AC-15 questions
Post by: ratgon on April 25, 2017, 08:47:12 am

Thanks!

No. It's the result of some experimentation I've been playing with. Instead of covering the amp after it's built I cover the Birch before I work it with fabric or paper or whatever and a very thin but incredibly tough and durable layer of epoxy resin. I'm basically veneering it. But it opens up unlimited finishes and it's forever.

And thanks for the EF86 info. I actually didn't think a 12au7 was a replacement but I figured I'd ask since God knows I don't know a lot. I just noticed there wasn't an EF86 on Dougs parts list AND I hadn't noticed the 12au7 in Sluckey's layout.

Thanks!

Title: Re: Finished PR build and Sluckey's AC-15 questions
Post by: pompeiisneaks on April 25, 2017, 01:20:15 pm

Looks very cool!

I'm possibly going to go back and put some kind of gasket on the EF86 socket as well as silicone rings, as it has a bad ring when I play it due to the microphonics of the damn tube :) (not really loud, just there and obvious).

~Phil

Title: Re: Finished PR build and Sluckey's AC-15 questions
Post by: ratgon on April 25, 2017, 07:07:24 pm

Thanks Phil!

And thanks for the heads up on the ef86. I haven't used one before but I've certainly heard about the microphonics. I just got some nice scrap .09 aluminum today to start to try and build a chassis for the next project. I can't seem to find a really spacious chassis like the one Sluckey used so I'll bust out my bending brake and see what I can do.

Title: Re: Finished PR build and Sluckey's AC-15 questions
Post by: ratgon on April 26, 2017, 07:40:30 am

Thanks! There it is. This'll kick the project into gear.

Thanks Sluckey.