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Old 30th November 2010, 08:30 PM   #1
THD+N is offline THD+N  United States
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Default Another 2A3 build

Here are a few pix of my Stereo 2A3 amp. The small foot print, is very heavy, about 50lbs, it is like picking up Lead or Gold, but in this case Iron.

Iron is from Edcor. 6SL7's and 5V4 are NOS US tubes. 2A3B's are Shuguang single plates.
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File Type: jpg 2A3 Kryptonite (45).JPG (647.6 KB, 563 views)
File Type: jpg 2A3 Kryptonite (48).JPG (659.5 KB, 517 views)
File Type: jpg 2A3 Kryptonite (40).JPG (665.1 KB, 513 views)

Last edited by THD+N; 30th November 2010 at 08:55 PM. Reason: Spelling
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Old 30th November 2010, 08:49 PM   #2
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I like your work "under the hood", and the compact footprint.

jeff
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Old 30th November 2010, 09:39 PM   #3
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Oh yeah... Excellent work! I love it when a plan comes together. Could you post a copy of the schematic?
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Old 30th November 2010, 10:07 PM   #4
jonboy is offline jonboy  United Kingdom
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What make are the transformers?
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Old 30th November 2010, 10:09 PM   #5
tim614 is offline tim614  United States
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LOVES THE LAYOUT!!!!!!!!
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Old 30th November 2010, 11:31 PM   #6
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Congratulations!

Point-to-point wiring, buss grounding, tube rectification, mmm...

What about a schematic?
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Old 1st December 2010, 12:27 AM   #7
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by THD+N View Post
Iron is from Edcor.
and nicely repainted

there's a lot of good knowledge in those pictures
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Old 1st December 2010, 12:41 AM   #8
THD+N is offline THD+N  United States
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I do not have a schematic drawn, but will draw one up and post in the next day or so.

Here are the Edcor model numbers used:
Output transformers are - CXSE25-4-2.5K
Power transformer is - XPWR118-120

For the money, the Edcor output transformers are definitely the "best buy". They have great low end extension and good high frequency response. My measured frequency response (-3dB points) is 7Hz~22.5kHz.

There was a strange low frequency anomaly (+ 0.5dB bump) between 5Hz and 20Hz, so I formed a low frequency cut-off with an input cap that brought my frequency response up smoothly starting around 7Hz.

I'll post a FR graph (with and without input cap) for comparison for those who are interested.
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Old 1st December 2010, 01:45 AM   #9
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Nice chassis. What was its previous occupation?
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Old 1st December 2010, 01:50 AM   #10
Matt BH is offline Matt BH  United Kingdom
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Nice

How did you get the crackle looking paint?

Cheers Matt.
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