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Old 6th October 2011, 06:38 PM   #41
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Join Date: Dec 2008
Location: Victoria, BC
Quote:
Originally Posted by data View Post
LOL, for a moment I thought the chassis was made from cardboard.

Doh!

https://picasaweb.google.com/aspring...30885357169874

Silly me
The 'scratch-prevention plastic covering was (one of the few) nice touches on mine as well.
At least they have the cutout for the lay-down PT in your chassis. Perhaps they took my 'complaining' to heart. ??

Be sure to put grommets for the transformer through-chassis holes on your shopping list. You will likely have to enlarge the holes to suit.

Now- do the transformer covers actually cover the transformer mounting ears?


Oh, and grab a couple of pieces of hardwood (you have lots of good stuff in Oz..) for the end pieces and chuck that Chinese particleboard....
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Old 6th October 2011, 06:46 PM   #42
data is offline data  Australia
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Too right we have, some Jarrah would look very nice on his chassis
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Old 6th October 2011, 07:16 PM   #43
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These Rifa's look old pulls, ewww. Some valves look old pulls to, but who cares, small signal valves last long. Resistors are nice, i like the yellow caps too. Ditch the old rifa's and you re good to go Round 1!
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Old 6th October 2011, 08:22 PM   #44
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Location: Perth, Western Australia
Default Pictures in the thread

Attempt #2 to get the pics in the thread.

I've had word back from the vendor about the used bits, and he's certain that the valves are all NOS. He's also offered to refund some payment back for the missing parts, so all good there. The most amusing bit of the message was

"The 2pcs capacitors are used. That is because the caps are better than unused.
It is to make the sound better. Sorry for that."

...Anyway, I'm pleased for the offer to either replace or offer a wee discount, so we'll see how we get on.

With regards to hardwood, I absolutely agree - I'll be replacing the ends on it with something much nicer (and yup, there's quite a bit of jarrah in the shed ) I'll probably build it with the existing parts for now, with a view to replacing bits when I get a chance to. Fingers crossed I'll get a bit done this weekend!

Today was a rather long work day, so I'll give the build a shot tomorrow.
Attached Images
File Type: jpg iron.JPG (98.8 KB, 309 views)
File Type: jpg transfo covers.JPG (69.1 KB, 301 views)
File Type: jpg valves.JPG (71.8 KB, 344 views)
File Type: jpg chassis.JPG (95.0 KB, 341 views)
File Type: jpg valves2.JPG (77.5 KB, 288 views)
File Type: jpg boxen.JPG (28.3 KB, 101 views)
File Type: jpg parts.JPG (85.3 KB, 191 views)
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Old 7th October 2011, 02:19 PM   #45
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Default A wee little play with the parts

..reveals a few issues.

Firstly, there's no appropriate mounting holes to suit the output transformers, and as has been pointed out previously by Victoriaguy the flanges for mounting the output transfo's are not covered by the covers. Hmm.

That said the power transfo does actually fit the hole for it, so I'm at least somewhat slightly mollified.... and the cover fits appropriately

I reckon I'll buy a few tagstrips before I kick this off.
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Old 7th October 2011, 02:32 PM   #46
data is offline data  Australia
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Yeah, a few issues, but as long as they are ones you can get around, it isn't too bad.

I'm looking forward to the end result dressed with some nice Jarrah

Edit:Just had a thought, can the output transformers be mounted with the flanges on the underside of the top plate and still be secure? Hmm...would mean a little metal work on the top plate or maybe a mod to the covers might be better? or making new covers might be easier damn, was hoping I could think of something to help

Last edited by data; 7th October 2011 at 02:37 PM.
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Old 7th October 2011, 11:04 PM   #47
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Data-
Here's the workaround I used for the OTs...
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File Type: jpg OT kludge.jpg (40.5 KB, 155 views)
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Old 19th October 2011, 02:49 AM   #48
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Ok, started a bit of work on the unit today. I've ginned up a couple of hardwood sides for the unit out of jarrah offcuts from another project I've on the go (photo's when I'm done finishing them).

I'm using tagstrips instead of the buss style build also. I'm a relative point to point novice here so if anyone has layout suggestions I'd be glad to hear em.

Pics to follow shortly.
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Old 19th October 2011, 05:53 AM   #49
data is offline data  Australia
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Nice thinking on the transformer mounting, straight forward with minimal energy spent

aspringv, with layout, try to keep it as symmetrical as possible, and as you would be doing anyway... keep signal and power apart. I have seen too many amps (especially retail) that have signal wires bunched with heater wires and such. Actually try to keep everything separate so you don't have fields from one wire influencing another, and where they have to cross, do so at right angles.

You are probably adhering to the above anyway, but thought I would just mention it.

Last edited by data; 19th October 2011 at 05:57 AM.
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Old 19th October 2011, 10:42 AM   #50
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Default going nicely

WIP photo. I've mostly wired up the power supply, although not as yet got the inductor in there. So far, kept it relatively tidy, but we'll see ho we go from here.

A few potential issues have come up. Firstly, I quickly fired up the transfo and got a few readings off it. All of the following readings are taken directly off the transfo without any load on it.

First up, the local mains is at 245V AC, whilst the transfo is wired for 220vac so all the secondaries are running a little high.
5v nominal- 5.8vac
6.3v nominal - 7.4vac
330v nominal - 365vac
So I'm a little concerned about these readings - I'll finish it all up and see what they read loaded.

Secondly, the schematic I'm following (attached, courtesy VictoriaGuy) states 1W resistors all round, and I'm wondering what the actual currents are at various points so I can see if I can substitute in some .25W parts I have on hand. Failing that I can just parallel up 4 at a time, but I'd rather avoid that if possible. The only exception to that is the 250R 5W off pin 8 of the EL34 - and I was wondering what the ramifications of using the supplied 330R parts would be? If someone with an understanding of how the circuit actually works could let me know that'd be helpful

Cheers all!
Attached Images
File Type: jpg cheapie amp part1.jpg (129.8 KB, 133 views)
File Type: gif Ezequiel SRPP EL34.gif (8.8 KB, 142 views)
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