Turtlerock Forum

I'm in the process of stripping down a friend's Rose Music Goldentone 1960's valve amp (2 channel, normal and tremolo) to see if I can track down a signal fault. For those unfamiliar these were Ozzie designed and built, usually point to point wired, valve amps. This one has a lovely Rola 12" AlNiCo for its speaker.

What I didn't know is that the tubes used in this thing (a pair of 12AX7s and a pair of 6GW8s) were also Australian made - a brand called Miniwatt. Apparently there were up there with Phillips and AWA as quality tubes. The 6GW8 was originally I believe designed as a TV signal amp tube, but adapted by a few Aussie amp designers for guitar amp use.

I really hope I can track this fault down 'cause I'd love to get this beast warmed up (yes, I do know about power and capacitor issues with old amps that have sat unused for a while) and give it a burl. But I am also lamenting the demise of Australian electronics manufacturing - we don't make valves here anymore, do we? ... and I know of perhaps one audio transformer manufacturer, out at Hornsby.

It's well worth getting that amp going Chris. There is a company here in Melbourne making hand wound transfirmers for audio. They are currently re building their website but it's worth a look.

http://www.black-art.com.au/audio/index.php

Contact Black Art
Black Art Audio, Melbourne, Australia

Australian Phone: (03) 9588 0643
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Hi Chris,
If you haven’t already then check out the Aussie Guitar Gear Heads forum (AGGH!)
http://www.guitargear.net.au/discussion/index.php

A wealth of information with some top amp builders/repairers often dropping in.

The Classic Australian Valve Amps page has a whole section on Goldentone, http://www.ozvalveamps.org/

Unfortunately, the originator of the page, Roly Roper, has passed away, but the enthusiasts from AGGH still maintain the page. It has details of the various models, including photos and schematic diagrams.

Well worth a visit.

Got sound out of it now, the two 12AX7's had blown. Ht and heater circuits check out fine so it was pop in a couple of new tubes and whammo.

Still a bit scratchy when it heads up, sounds like a solder joint issue.

I have also inserted a connector jack between the amp and the footswitch so you don't have to keep a heavy loose bit of metal banging up against the speaker cone during transport, and also put a switched jack between the speaker and the amp (switched so that there is an 8R resistor across the outputs if the plug is pulled, meaning there is always a load across the output - important when dealing with tube amps).

I'm also looking to tidy up the power supply wiring a bit, but then it's probably ready to go back to its owner.

No circuit diagram for this '64 model online so I had to trace it all out - which, sick puppy that I am, was great fun!

Congrats Chris!!!

I remember (just) in around '66/7 using a mate's G'tone at a "show" we did at our high school fete. It think it was a 40 watter with twin 12" speakers.........kick arse compared to my 25 watt FiSonic

Damn - all done so have to hand it back today. Tone and trem circuits all working as they should. 15W of Aussie valve history and it sounds sooo nice. I have new respect for Rob@Harmonic and the other techs on this forum who constantly have to give back great gear to its rightful owner.

Got myself a Lamington 15W kit from Grant at Valve Heaven, so hopefully I won't have to go cold turkey for too long.

Though it is a struggle to give back great sounding amps sometimes, as a tech you know another will soon come along. The greatest pleasure, though, comes from getting an old amp that doesn't work and returning it to its former glory, nothing compares with that feeling.

stosostu wrote:The greatest pleasure, though, comes from getting an old amp that doesn't work and returning it to its former glory

Preach, brother. I got shivers when this thing came alive after a decade.