Forums - First time build

mboxler

Senior Member

Posts: 69

Re: First time build
Reply #30 - 01/04/13 at 14:50:46

My "plate" is 8X8.

As you can see in post 23, as long as the two holes you drill to pass the wires through the plate are not on top of the board, you should be okay. My enclosures were a little small, and the first time, I had the PS transformer turned 90 degrees from where it is now. That's when I realized the wires were above the board, and difficult to work with.

I have an inch clearance between the holes and the board, and had no problem. Unfortunately, the transformers overlap the board by and inch, so a couple of board mounting screws are under a transformer.

Reminder. I was told it is a good idea to turn the PS transformer 90 degrees from the OP transformers.

With my setup, 10 inches wide and 9 inches deep would have been much easier to work with. Again, I'm using the PCB mounted pot, so the board is 1/8 inch from the front. If I had used a separate pot, I would have needed more room in front.

Good luck guys!

Mike

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jpv

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Posts: 110

Re: First time build
Reply #31 - 01/25/13 at 01:22:25

Ok find the mistakes. Don't look too hard.
I got the plate I am mounting the board to cut and painted. I used a heavy guage steel and would go with a much thinner metal next time. It was a major pain to cut. The plate is big 12 x 18 and gives me plenty of room.
I was going to cut it down but I figured I could use the room and it looks nice. I have from the top left, a standby switch, Power switch and the volume control, The power transformer on the left, Holes for the tubes then the two speaker transformers. On the bottom is the power jack, two sets of inputs, The small hole is for a toggle switch to select the input, then the speaker post holes.

So now that I am ready to assemble whats next?
I put the input and selector switch on and mounted the speaker post.
I am not sure how to ground this. If the wires need to be twisted, separated, or any of the little details going from here on.
Do I complete the build then power it up or do I test it before I get to far?

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VPI Scoutmaster, Grado Sonata1, Counterpoint pre amp and amp (modded by Altavista Audio), Proac sp. and home made subs. Lots of room treatment. Anti-cable sp cables, Decware IC, ZKit 1.

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mboxler

Senior Member

Posts: 69

Re: First time build
Reply #32 - 01/25/13 at 15:24:52

Hi John...

Don't you hate learning curves? I'm glad I started with aluminum...easier to drill.

Did you use step down drill bits? If not, an investment would do wonders, although I don't know how much they would cost to deal with heavy gauge steel. You can easily round out the holes, and smooth out the edges. The holes you drilled for the transformer wires need to be very clean, or do what I did and buy rubber grommets to "snap" inside the holes to prevent cutting the coating around the wires.

I tested my board "outside the box". Granted, it meant a lot of temporary solders, but I wasn't brave enough to put everything together first. You may be braver!

The most important ground is attaching the IEC ground to the chassis. This can save your life. Drill another hole a couple of inches from the IEC hole, and run a short wire from the IEC ground to a bolt through that hole. I used a bolt, nut, washer, and lock washer. I ended up attaching the chassis ground to this as well. Make sure you scrap any paint from the edges of the hole. You want a good electrical connection.

I've been told...always twist wires. I could only twist the heater wires, as everything else had such short runs that I had no room to twist.

If two sets of wires cross, make sure they cross at 90 degrees, if possible.

This part of the project is nerve racking. Take youe time.

Mike

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jpv

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metal kid

Posts: 110

Re: First time build
Reply #33 - 01/27/13 at 18:37:57

Here is an overview of the backside so far. The red/black wire has not been attached yet. I have one SPST switch with nothing going to it yet. The plan is to use it for a stand by switch. I need help with that.
I have it grounded in from two spots. One IEC groung and the Chassis Ground. Is that all I need?
Do you see any mistakes with what I have done so far?

Once I get this looked over I will do the power up. I will post that later.

John

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VPI Scoutmaster, Grado Sonata1, Counterpoint pre amp and amp (modded by Altavista Audio), Proac sp. and home made subs. Lots of room treatment. Anti-cable sp cables, Decware IC, ZKit 1.

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mboxler

Senior Member

Posts: 69

Re: First time build
Reply #34 - 01/27/13 at 20:03:09

I can't see anything wrong. Actually, without the red/black CT wire attached, you could fire it up! The brown wires are connected, so you should see the tube filaments glow. That will be cool! Uh, I mean hot. Great first test. There will still be high voltage going thru the diodes, but without the center tap wire connected, the voltage cannot be rectified. The buck will stop there. Make sure the loose red/black wire cannot touch anything.

Now you will understand how to hook up the red/black center tap wire. Run the red/black wire from the transformer to the second switch. Run a wire from the other pole of the switch to red/blk on the pcb. Actually, I'd call the first switch the standby switch, as it will only conduct heater current. The second switch will power on the amp.

Turn on sequence...

1) Standby switch on. Let tubes heat up for 20 to 30 seconds.

2) Power switch on. B+ DC current can now flow, because the power supply has a center tap. Now you can measure test points.

Turn off sequence...turn both off at the same time, or turn off the power switch, followed by the standby switch.

Make sense?

Mike

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jpv Seasoned Member Cause inside everyone is a heavy metal kid Posts: 110	Re: First time build Reply #35 - 01/27/13 at 21:14:39 Does the Volume control need to be grounded? I see a Ground case of Vol control on th PCB. What is that for? When is it used? John
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mboxler Senior Member Posts: 69	Re: First time build Reply #36 - 01/27/13 at 23:22:53 From Nimrod...scroll to the bottom http://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1341162665/all I used the pots soldered to the board. Perhaps you could PM him for more specifics. Mike
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jpv

Seasoned Member

Cause inside
everyone is a heavy
metal kid

Posts: 110

Re: First time build
Reply #37 - 01/31/13 at 02:19:35

Well It works

No smoke, Hum,or exploding parts yet.
My plan is to run it for the next hr or so and do this a few times until I am sure it all OK. Then it on to the main system.
Right now I have it hooked up to the PC audio outs. Sound good thru the POS speaker I am using to test.
The voltages measured in the range.
I will post photos later.

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VPI Scoutmaster, Grado Sonata1, Counterpoint pre amp and amp (modded by Altavista Audio), Proac sp. and home made subs. Lots of room treatment. Anti-cable sp cables, Decware IC, ZKit 1.

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jpv Seasoned Member Cause inside everyone is a heavy metal kid Posts: 110	Re: First time build Reply #38 - 02/01/13 at 00:54:11
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jpv

Seasoned Member

Cause inside
everyone is a heavy
metal kid

Posts: 110

Re: First time build
Reply #39 - 02/01/13 at 01:22:02

The picture in the previous post is the underside of this amp. I put the labels from Edcor on the plate for reference. I tried to keep the wiring as neat as possible. I mounted the 3 large resistors on the socket side to keep the heat producing items on top. The speaker wires are connected directly to the binding post bypassing the PCB.
I also color coded the wire with shrink tubing red right blue left.. Just a little OCD :)

There is a front view. I have two power switches the rt side one is the power for the heaters. Next to that is the power to turn the power on to the rest of the system.
In the rear are two sets of inputs and toggle switch. IEC plug on the rt and the speaker post on the left. The base is red oak stained and polished with a satin wax.

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VPI Scoutmaster, Grado Sonata1, Counterpoint pre amp and amp (modded by Altavista Audio), Proac sp. and home made subs. Lots of room treatment. Anti-cable sp cables, Decware IC, ZKit 1.

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mboxler Senior Member Posts: 69	Re: First time build Reply #40 - 02/01/13 at 14:23:59 Great Job! Love the red oak. You may have mentioned this already, but what kind of speakers will this amp drive? Mike
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jpv Seasoned Member Cause inside everyone is a heavy metal kid Posts: 110	Re: First time build Reply #41 - 02/01/13 at 14:38:25 Well thats my next project for the spring time. I will hook this up to my main system and see how it does driving Proac Tablettes. My other thought is to create a desk top speaker to use with my PC. I need to research ideas on what is out there.
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jpv

Seasoned Member

Cause inside
everyone is a heavy
metal kid

Posts: 110

Re: First time build
Reply #42 - 04/29/13 at 00:36:13

Well it has been a few months since I finished and I have done a lot of listening. I am really happy with the results. While the amp doesn't have the power my SA-12 has, I can get my Proac Tabeletts to an good listening volume. I did have a friend bring over her Klipisch Heresy speakers. Now that was the ticket. She was amazed how a 2 watt amp could "get so much sound out of them". We played music until 3:00 AM
What was really crazy her kids in their 20's never saw a LP or a turntable before.

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VPI Scoutmaster, Grado Sonata1, Counterpoint pre amp and amp (modded by Altavista Audio), Proac sp. and home made subs. Lots of room treatment. Anti-cable sp cables, Decware IC, ZKit 1.

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