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Hoffman Amps Forum image Author Topic: Hi  (Read 2966 times)

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Offline 74-335

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Hi
« on: January 11, 2020, 07:10:54 pm »
Hello friends,

I've been lurking on and off for a couple of years here and never felt confident enough to post any questions, due to my relative lack of experience in amp building / modding.

I'm in my mid 40's and actually do have an electrical background, but an accident several years ago has left me with some 'brain issues' (let's just leave it at that).

Some time ago I took up guitar, after a 20+ year hiatus. I have been a pianist for 35+ years and guitar was a bit of a fleeting impulse in my late teens and early 20's.
With this re-acquisition of 6 stringed instruments has come a few amplifiers of popular brands: I have a reissue 65 twin which is only a couple years old, an early 100w silver face quad, a '70's JC-120 (pre bright switch chrome corner) and a more modern Vox NT-15 head, and the venerable Boss Katana 100 (which is really a very nice amp!). Throw in some chinesium fender SS heads and other associated junk and I'm suddenly inundated with gear. Can't help it.

The one thing I am lacking is a JTM-45. I do have a nice 1960 vintage 4x12 which I currently plug the Vox head into, and it has a nice sound, but it's no Marshall.

Something I would like to know from the experienced and experts here, is whether or not the JTM is worth building or is it better to buy one or a clone, like a ceriatone for example.

Live in Australia so exchange rates and costs for shipping and taxes really do hamper the purchase of things like Mercury transformers and the like, so perhaps someone could advise if a used and half-decent built clone would be worth picking up and working on as a project (mods might be cost-effective also?)

Lastly, The initial reason I found this site years ago was because of the epoxy glass turret boards, which Hoffman amps sells, and I always wondered if I could pull the PCB from my twin reissue (ab763) and "go retro".  The other thing is that my quad is getting old now and it needs some "Overhaulin' " so to speak. the serial number dates it to early 1973, it's a 100w master vol no push-pull though (so not the ultra linear silverface).

I am trying to get the correct factory grille cloth for this sylverface quad reverb also - to pretty it up a bit, but no-one seems to have the correct cloth.

Apologies for the long intro, While I have over the years perused several topics here, I have not been able to work out if I can use any of the turret boards in the fender amps, or if I must use the eyelet boards.

I have successfully overhauled the JC-120 and corrected the usual issues with chorus and mono issues, so I'm not a complete vegetable. I can still read schematics and test circuits, I'm able to solder 0402 Smd's so I can do stuff, but my learning process is impeded by the knock on the head and it takes some time to digest. Please forgive if I offer repeated questions or statements in this regard, but remind me if I do it, so I can correct myself.

thanks
If you grab it with both hands, chances are, it'll shock you.

Offline sluckey

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Re: Hi
« Reply #1 on: January 11, 2020, 09:00:55 pm »
If I lived in Australia I would shop at Ceriatone.

You can certainly put Hoffman's board in a TRRI. But if the amp is working fine I would not, unless I was just bored and wanted a challenge. It's more involved than just swapping the boards out.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline 74-335

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Re: Hi
« Reply #2 on: January 11, 2020, 10:40:25 pm »
Thanks Sluckey.

I will give Nik a call tomorrow and have a chat with him.
If you grab it with both hands, chances are, it'll shock you.

Offline Ritchie200

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Re: Hi
« Reply #3 on: January 12, 2020, 12:16:51 am »
You can just run down to Dick Smith and pick up anything you need, right?  Just kidding!  Welcome aboard!  There are lots of nice folks here that will lend a hand when you need it.  Looking forward to seeing and hearing your new build!

Jim

My religion? I'm a Cathode Follower!
Can we have everything louder than everything else?

 


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