Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Cabinets-Speakers => Topic started by: Sonny ReVerb on September 04, 2017, 03:21:29 pm

Title: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on September 04, 2017, 03:21:29 pm
Got some work done on the cab for my Ampeg R12-R variant. I had to build a new crosscut sled first, because my old one warped while in storage. If anyone is interested, check out William Ng's videos on YouTube. He's an excellent woodworking teacher that shows how to build an accurate crosscut sled (https://youtu.be/UbG-n--LFgQ) and a finger joint jig (https://youtu.be/NutwD7B6tmE).

Probably sacrilegious, but I'm putting an Ampeg circuit in a Fender style cab. I've done several head cabs and a 1x12 speaker cab, but this is my first blackface style combo cab; not an easy shape to duplicate. It turned out pretty well, so far. Close enough to square, but my clear pine revealed a nice flaw when I made my final cut. A little wood filler did the trick.
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on September 04, 2017, 03:22:55 pm
Test fit...
Title: Re: Cab for my Ampeg R12-R variant
Post by: sluckey on September 04, 2017, 04:26:36 pm
You may want to put some "bear claws" on those tubes...

(http://hoffmanamps.com/MyStore/catalog/images/springfender.jpg)
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on September 04, 2017, 04:50:10 pm
I considered retainers, but most of the 60's amps didn't use any. This will most likely be a home amp that might journey to a blues jam once in a rare while. Do you think there is much of a problem with tubes falling out of the sockets? It's a bit of work to pull them out.
Title: Re: Cab for my Ampeg R12-R variant
Post by: bnwitt on September 05, 2017, 07:52:29 am
I think current quality on modern day tube sockets warrants the retainer clips.  The chassis looks pretty tight without Tolex.  Will it fit once covered?  Or are you just staining?  Box looks great by the way.  no knots?  That looks like clear high quality pine for sure.
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on September 05, 2017, 03:46:23 pm
Thanks, Barry. The fit is a bit tight. I measured my stock to length, but didn't allow for any extra. Since I made the fingers 1/32" proud I lost 1/16" in length. Just enough for a couple of layers of Tolex. The Tolex is pretty thin, but I'll probably have to get busy with the sandpaper to make a little room.
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on September 10, 2017, 09:17:29 pm
Anybody like blondes?
Title: Re: Cab for my Ampeg R12-R variant
Post by: sluckey on September 10, 2017, 10:07:39 pm
That's sexy! Does the chassis fit?
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on September 10, 2017, 10:27:44 pm
Yes. You can probably see in the shot of the back that I had to sand in a bit of relief. I would call it a precision fit, however next time I would not build it quite so precisely  :icon_biggrin:

I'll add some shots of the finished item tomorrow.
Title: Re: Cab for my Ampeg R12-R variant
Post by: bnwitt on September 12, 2017, 08:24:08 am
Very nice job Sonny!  Good work on the tolex corners for sure.  Very professional.
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on September 12, 2017, 02:26:15 pm
Thank you, Sir! The cab did turn out pretty nice. The grill cloth could be straighter...

Here are a couple more pics:

Title: Re: Cab for my Ampeg R12-R variant
Post by: davidwpack on October 05, 2017, 05:22:41 pm
Nice! I recently became an Ampeg convert after restoring two vintage B25-B heads. Amazing sound those Ampegs ey? I think my next scratch build will closely model the Ampeg preamp. They work exceptionally well for OD/distortion pedals too in my opinion. Again, nice work!
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on October 08, 2017, 10:22:11 am
Thanks. I agree, these amps sound really good. I took this one to a local blues club and had a friend give it a go. He played through it for a whole set. He was playing a Gibson ES-150 in a trio. I thought it sounded killer. Afterwards, he commented particularly on the reverb, saying it would be cool as a standalone unit (build idea?). He also said he could turn it up without feedback from the hollow body, which was unusual.

I'd like to try adding the tube driven reverb circuit to some other amps.

From Wikipedia:
Quote
In 1961, Ampeg became the first company to incorporate reverberation (reverb) in an amplifier with its Reverberocket, which preceded Fender's Vibroverb amp by nearly two years.
Title: Re: Cab for my Ampeg R12-R variant
Post by: davidwpack on October 08, 2017, 12:25:08 pm
Yeah, I've got a '67 ES 330 (fully hollow with P90s). I can get the Ampegs remarkably louder and standing a lot closer compared to my Laney and my KT66 scratch-build before feedback. Ampegs are simply pure magic to my ears and I cannot say enough about them. Also, I was wondering; are your power tubes the 7027As?
Title: Re: Cab for my Ampeg R12-R variant
Post by: Sonny ReVerb on October 08, 2017, 02:57:57 pm
No, I followed the early R12-R schematic mostly (different tone stack) and used 6V6's.