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Old 15th February 2013, 07:41 PM   #281
PWR RYD is offline PWR RYD  United States
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Is the schematic in post #126 the latest and greatest?
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Old 15th February 2013, 08:04 PM   #282
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Yes, that is the latest except for the addition of the LED driver tube bias option.

I have attached the info for that. Whether it sounds "better" with LED bias or conventional RC bias is a personal preference.

There are a couple of other versions of the circuit, one includes plate-to-plate feedback which in my opinion slightly degrades the "open" sound of the amp.

It is important to use the LC filters for the driver tube plates, instead RC filters like in some versions.
Attached Files
File Type: pdf LEDbias.pdf (32.7 KB, 93 views)
File Type: pdf LEDbiasinstructions.pdf (36.0 KB, 63 views)
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Old 15th February 2013, 08:08 PM   #283
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Here is the schematic and chassis layout so folks don't have to go search for post #126

Also the choke, L1, for the driver is Hammond part# 155H.
Attached Files
File Type: pdf setschematic.pdf (61.5 KB, 137 views)
File Type: pdf setchassislayout.pdf (64.6 KB, 64 views)
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Old 15th February 2013, 08:34 PM   #284
PWR RYD is offline PWR RYD  United States
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Thanks Scott. I am considering scratch building this design with an Allied 6K7VG power transformer and Edcor GXSE15-6-5K output transformers. Will that iron work pretty well? I already have the 5U4GB and KT88's. I also have some 6DJ8s that might work in place of the 6N1P.
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Old 15th February 2013, 08:51 PM   #285
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Yes, that iron will work well. You will get better frequency response if you use the Edcor CXSE version, although at a substantial cost difference. I used the GXSE in my first build of this version and they do sound good. I believe user "skippyboy" is using the GXSE. Maybe he will chime in here.

Definitely do not use the 6DJ8 in place of the 6N1P for this design. If you need a 6N1P-EV, send me a PM. We can work something out. I have a bunch of them.

Scott

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Originally Posted by PWR RYD View Post
Thanks Scott. I am considering scratch building this design with an Allied 6K7VG power transformer and Edcor GXSE15-6-5K output transformers. Will that iron work pretty well? I already have the 5U4GB and KT88's. I also have some 6DJ8s that might work in place of the 6N1P.
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Old 15th February 2013, 09:14 PM   #286
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FYI:

The 6 position terminal strip is Mouser part #534-829TS.

The turret board is Mouser part #534-15293. Comes as 5 sections of 5 positions each.
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Old 18th February 2013, 12:29 PM   #287
PWR RYD is offline PWR RYD  United States
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Thanks Scott. How do the custom transformers you supply with your kit compare to the GXSE and CXSE?
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Old 18th February 2013, 12:41 PM   #288
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Quote:
Originally Posted by PWR RYD View Post
Thanks Scott. How do the custom transformers you supply with your kit compare to the GXSE and CXSE?
They compare to the CXSE. All kits are sold though.
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Old 4th March 2013, 07:02 PM   #289
PWR RYD is offline PWR RYD  United States
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I picked up some green LEDs for the driver tube bias. Two in series measure a forward drop of 3.686 V. Is this okay?
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Old 4th March 2013, 08:09 PM   #290
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Yes, that will work fine.

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I picked up some green LEDs for the driver tube bias. Two in series measure a forward drop of 3.686 V. Is this okay?
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