Utopia, can you tell us more about your GM70? I will have mine done in a couple weeks. I am running a two stage at 850v B+ driving the GM70 with a 12HL7 with a CCS on the HL7. Here is a pix so far. Also, what are you doing for the filliment PS?
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I've seen so many of other folk's projects on this forum, so I figured I'd get in on the action, too. Pictured here is yet another RH84. Since I happened to have a pair of Hammond 125ESE's lying about, I breadboarded the circuit just to see what all the fuss was about - and it sounded incredible! Good enough, in fact, for me to spend some serious coin on the pair of nice James 6112HS OPT's for the final build.
The PT is a Hammond 270HX (275-0-275, 200 mA); the filter choke is a Hammond 193H (5H @200 mA). The end bells were stripped of the old finish and painted with a satin black heat-resistant paint. I wound up using a 5V4 rectifier instead of a 5U4 to shave 1A off the filament current and provide a "soft start". The meters monitor both power supply voltage and current, and were purchased from Weber Kits (yes, I know the meters aren't registering in the photo - the amp had been switched on just before snapping the shutter).
I constructed the chassis frame of Brazilian Cherry (Hymenaea courbaril). The corner columns were turned from curly maple and regular (American) cherry. All woodwork was given a coat of sanding sealer, sanded smooth, and finished with three coats of spray lacquer. The aluminum deck was lightly sanded and given several coats of hammer-finish paint. The light spots on the paintwork aren't chipped paint, BTW; they're just reflections from the lights I used.
The PT is a Hammond 270HX (275-0-275, 200 mA); the filter choke is a Hammond 193H (5H @200 mA). The end bells were stripped of the old finish and painted with a satin black heat-resistant paint. I wound up using a 5V4 rectifier instead of a 5U4 to shave 1A off the filament current and provide a "soft start". The meters monitor both power supply voltage and current, and were purchased from Weber Kits (yes, I know the meters aren't registering in the photo - the amp had been switched on just before snapping the shutter).
I constructed the chassis frame of Brazilian Cherry (Hymenaea courbaril). The corner columns were turned from curly maple and regular (American) cherry. All woodwork was given a coat of sanding sealer, sanded smooth, and finished with three coats of spray lacquer. The aluminum deck was lightly sanded and given several coats of hammer-finish paint. The light spots on the paintwork aren't chipped paint, BTW; they're just reflections from the lights I used.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Here's my new Moebius preamp...
http://img202.imageshack.us/img202/8306/img0251ux.jpg
http://img177.imageshack.us/img177/8058/img0252r.jpg
http://img202.imageshack.us/img202/8306/img0251ux.jpg
http://img177.imageshack.us/img177/8058/img0252r.jpg
Just an ST-70
I rebuilt/restored this ST-70 from a rusted junker a few years ago. I had been rarely using it, but now does daily duty on my main system.
I had the bell covers nickel plated. PTX is the upgrade model from Triode Electronics. driver board is from diytube. Input transformers are from Jensen. I added a brace on the underside going across the long way under the transformers to make the chassis very solid.
I rebuilt/restored this ST-70 from a rusted junker a few years ago. I had been rarely using it, but now does daily duty on my main system.
I had the bell covers nickel plated. PTX is the upgrade model from Triode Electronics. driver board is from diytube. Input transformers are from Jensen. I added a brace on the underside going across the long way under the transformers to make the chassis very solid.
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The place I ordered the components, didn't have 82 ohm resistors, so i put 10 820 ohm resistors in paraller...
preamplifier 4P1Ł
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
