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Old 26th October 2010, 07:00 PM   #1
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Default My first build VTA ST-120

I have wanted to build an amp since I saw my first Heathkit as a youth in the early 70's. Ten years ago I bought some Zen boards and built enclosures but got intimidated and stalled in the parts selection.

The VTA kit was high quality and all inclusive with great attention to detail and clear instructions. It was easy to build. Blue and white wire to tab V6. No theory needed.

I made some changes as you can see. I wanted all connections in the rear and upgraded connecting hardware and wire and used 4 carbon resisters.

I'm proud and thrilled. It sounds fantastic too.

Fred Griffith
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Old 26th October 2010, 07:35 PM   #2
taj is offline taj
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Well done! Nice maple cabinet too. It really spruces up an ST-70 chassis. What's next on your agenda now that the intimidation is gone?

..Todd
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Old 26th October 2010, 10:39 PM   #3
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Thanks!
I have a PCB for a B1 passive buffer on the way then who knows, maybe another amp.

FG
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Old 27th October 2010, 04:04 PM   #4
kevinkr is offline kevinkr  United States
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Exclamation Serious Safety Ground Issue!

Quote:
Originally Posted by sawdusttt View Post
Thanks!
I have a PCB for a B1 passive buffer on the way then who knows, maybe another amp.

FG
Very very nice, but you need to make one urgent change, and that is the safety ground from your IEC power connector needs to be connected directly to the chassis at both the rear panel and the main chassis. Should there be a fault the ground current will flow through your signal ground wiring which is not safe. (In this case the shield of your input cable)
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Last edited by kevinkr; 27th October 2010 at 04:08 PM.
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Old 28th October 2010, 05:51 PM   #5
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Hi Fred,

Glad to see that you used shielded cable on the input cables when you moved them to the back panel. When the input wires are on FRONT of the amp there is a short run of about 1 3/4 inches of wire from the driver board to the input jacks and noise pickup from the amp itself is not an issue. When you move them to the rear of the amp, however, those input wires will be more prone to picking up noise from the power transformer. A nice clean looking build. The maple base looks really nice with the amp ..

Bob Latino
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Old 28th October 2010, 08:21 PM   #6
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"Very very nice, but you need to make one urgent change, and that is the safety ground from your IEC power connector needs to be connected directly to the chassis at both the rear panel and the main chassis."

it's hard to tell if the rear access panel is "STAR" grounded to the main chasis, OR, if the screws that secure the rear access panel screw into the main metal chasis or just the wood case.

definitely something to check into.
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Old 17th November 2010, 08:36 AM   #7
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Thank you for the complements and for pointing out my need for a star ground.

Thanks again!

FG
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