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so then.... [message #31102 is a reply to message #31101] |
Sun, 22 May 2005 07:27 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
PakProtector
Messages: 935 Registered: May 2009
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Illuminati (2nd Degree) |
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With an 8k a-a, B+ can be 360 V, plus 75-80V of cathode bias, and B+:ground can be 450. No problem getting a 200v p-p swing( per plate ) out of a supply like that. Go to 10k a-a and we can be absolutely sure of Class A operation if bias is in the 80-90 mA area. Use a CCS instead of a resistor, or perhaps an unbypassed R for the cathodes. I suspect the R will give better overload performance than the CCS. I'd rather build a low gain pre like Guinevere with 12B4's and roll a bit of gain into the adjustable volume control/buffer stage. Or take 12B4's and keep the 5687 gain of Guinevere. there is something to be said of two stage amps and linestages with gain. Work together on system requirements instead of building the whole thing to a specific standard of sensitivity( which will set limits on tube choice somewhere in the chain...). regards, Dogulas Praise the Lord, and pass the 813's!
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Re: so then.... [message #31104 is a reply to message #31103] |
Mon, 23 May 2005 19:08 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
PakProtector
Messages: 935 Registered: May 2009
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Illuminati (2nd Degree) |
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Hey-Hey!!!, I am building a pair of monoblocks with 4E27 finals. It is a valve somewhere between a HY69 and an 813 in ratings and dissipation limits. L-C power supply of between 600 and 700 volts. Current delivery of ~300 mA. Ultra-Linear rigging of the finals and E-Linear front end. Cascode differential amp like Merlin. I am not exactly sure how the finals like their U-L connection, so I will be fairly sure of getting where I want to be with those options.I need to get paid a few times before I order the Iron, but I don't think anything will change very much. I have been fairly sure of this design for a bit now. It's just a matter of scale, those OPTx's would be just as happy with a pair of EL84's as 845's. Still need to decide upon the specifics of the cascode front end, there are quite a few options. I will be posting notice before ordering the OPTx's so as many folks as possible can throw in their money and net us a good price on a bigger run of them. regards, Douglas
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Ha! [message #31124 is a reply to message #31095] |
Sun, 29 May 2005 06:40 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) |
PakProtector
Messages: 935 Registered: May 2009
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Illuminati (2nd Degree) |
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I like this Al guy already. I must find a way to make his acquaintance. regards, Douglas
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