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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: In Pentode, G2 is of prime importance posted by drlowmu on August 7, 2012 at 10:24:19:
For G2 supplies :Here are ALL the magnetic parts, off the shelf stuff, no part truly "audiophile inflated" in cost, just Jeff's picks, "the real deal" :
(1) 6 Ohm DCR Power Transformer; Signal Transformer Co., Model A41-175-230. Digikey P/N 595-1307-ND, rated 175 VA, or 760 mA !!! $49.42 for an "under ten Ohm, Ultra High Fidelity" part.
All I will tell you is, "don't live this life without a UNDER ten Ohm DCR PT in your tube audio amp."
(2) L1, 72 mHY is a Signal Transformer Co, dual choke, Model Number CL-1-2. Rated at 1 A. and ONLY 1.4 Ohms DCR as configured, it won't buzz. Digikey P/N 395-14307-ND, only $19.77, one of the biggest bargains in audio, under 10 Ohms = "Ultra High Fi ". Weighs UNDER one pound. Low in stored energy.
(3) L2, 1.5 HY at 17 Ohms, EDCOR model XC75-1.5 HY at 250 mA., lists at $26.13. Small, low in mass/stored energy, and beneficially, open frame, no end bells to mess it up. Three week delivery.
(4) L3, 2 HY at 29 Ohms, EDCOR model XC75-2 HY at 200 mA., lists at $26.13. Small, low in mass / stored energy, and beneficially open frame, no end bells to mess it up. Three week delivery.
We should consider this : ALL THREE of these industrial-made and priced Ls are less than the cost of just ONE high mass and high DCR, clunky "audiophile" LuXXXhl choke. Audio "give-away" here, like a JJ-2A3-40.
(5) The current-drawing resistor MUST ONLY be a Mills MRA-12, of proper Ohmic value. Michael Percy, 5 or 6 dollars.
(6) The 54 uF part can be a (newly designed 105 degree C) Nichicon KX audio-grade cap, value is 56 uF at 450 VDC. and it is INexpensive, a few dollars. Parallel two more for the 110 uF final cap in this G2 filter.
(7) Double Kimber Kable TCSS wire this entire supply, right to the G2 pin on the tube socket.
(8) One other circuit twist .....DO not forget to put a John Swenson snubber, between the power transformer's secondary HV winding, (a C and R, connected in series, and then placed in parallel across the HV winding) and the solid state rectifiers.
(THIS SNUBBER IS NOT SHOWN IN PSUD SIMULATION SCHEMATIC !!)
It will be John's suggested values : 0.022 uF and 330 Ohms. Wima nicely makes a 4,000 VDC rated part, 5 or 6 dollars, BUY that one, which should NEVER fail.
Hey, hey, hey, we are putting a power supply on a GRID, so this snubber is justified, 'will be audible improvement on G2 - big time !!
--------------------------------------------
Now buds, after about 80 years, there is NO more excuses for you to be listening to that nasty sounding, perturbated U.L. (ultra NON linear) connection on your G2......OR, that nasty and non-transparent-sounding actively regulated G2.
William Z., do you ever read my posts ?? This could be ideal for your big "Reference" series amp.
Wake up everyone and smell 'de roses. Circuit suggestions are welcomed and encouraged.
Cheers.
Jeff Medwin
BTW, my friend JLH could also use this separate G2 supply advantageously in his pentode LCR preamp.
Edits: 08/10/12 08/10/12 08/10/12 08/10/12 08/10/12 08/11/12 08/12/12
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Follow Ups
- G2 Parts List......Magnetics. - drlowmu 05:50:06 08/10/12 (3)
- MrBob: Regulation - gusser 11:52:07 08/10/12 (2)
- Sorry, I don't know much about boutique wire.. - gusser 12:28:47 08/10/12 (0)
- RE: MrBob: Regulation - drlowmu 12:13:42 08/10/12 (0)
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