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Old 28th November 2003, 07:52 PM   #11
gyusher is offline gyusher  United States
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Default Wow. . ., . .

I think I will owe everyone an explanation. . . When I posted my first post I was put in Moderation as every new member. . .When the post came out and no picture I thought I had done something wrong so I kept posting pics. . .Looks like they might all show up at once. Believe me I am proud of this amp but not that proud. . .Please forgive my eagerness to get started. . . . .
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Old 29th November 2003, 12:16 AM   #12
gyusher is offline gyusher  United States
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Default Now at Normal. . .

I see the over see-ers took the excessive pictures out. at least someone was thinking, it was not me.
Now I will say Hello again. . .I am interested in whats going on here even if I dont understand much of it. I have a lot to learn and what better way than to learn from the best in their field. I look forward to adding to the discussion when I can and its appropiate to do so. Mostly I enjoy reading your back and forth discussions.
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Old 29th November 2003, 06:30 AM   #13
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Don't feel bad. I don't know how to work this thing either.
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Old 29th November 2003, 08:37 AM   #14
gyusher is offline gyusher  United States
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Default Easy. . . . .

"Don't feel bad. I don't know how to work this thing either."

Thanks for the kind words. . . Let me tell you what I had done to the model 3 Forte'. This is a list prepared by the "Fixer" when he repaired my amp.
"Forte’ Model 3 enhanced” 10-18-03
1) Replaced the stock 700 VA toroidal with two 600VA units for dual mono operation.
(Actually I checked the original Toroid, it was only 1 volt lower than the ones I put in).
2) Replaced the 12000mfd per side (24000 total) capacitance to 40,000mfd per side (80,000 total). The replaced caps are superior grade Cornell Dubilier 100 volt types (stock were 45/90 volt types).
3) Replaced the two 25 amp bridge rectifiers with 50amp parts.
4) Performance was enhanced to Dual mono, power into 8 ohms from 200 to 250 watts and 4 ohms from 300 to 410 watts.
Turn on rush will be about the same as the 565 you have. The 565 have about 70,000 to 75000 mfd's while the Forte has 80,000 mfd's.
The Forte can be used with a Variac to up the voltage without any problems (i.e. 140 volts AC instead of 120) in such a mode, it will give you about 380 watts RMS into 8 ohms. That means it will act like 2 565's. However in that mode it should not be driven into 2 ohms whilst the 565 can. Under normal voltages, the Forte CAN be paired up with 2-ohm loads. (i.e. 120v ac not 140 v ac)
Caution: Do not try to up the voltage on any Adcom, you will fry the outputs. They are rated at 90-0-90 volts DC Max while the ones in the Forte are rated at 100-0-100 volts DC. (The nominal rails on the Forte is about 79-0-79 and after you up the AC side to 140VAC, the DC rails will go up to 92-0-92) as you can see at 92-0-92, the Adcom's outputs will blow yet the Forte's will be OK.
Funny thing, Toshiba invented the perforated emitter technology and came up with the devices used in the Adcoms (D424/B554) then sold it to Motorola. The replacement devices that Toshiba made were the first "Super-Beta" devices i.e. do not lose current drive into lower impedance’s, and these are what are used in the Forte's (A1302/C3281).
Infact many Luxman, Carver, Sunfire etc. amps use these same devices. They have the reputation in the industry to keep constant distortion even into lower impedance.
Well, by virtue of installing 2 toroids instead of 1, the amp will clip at higher levels than before because the 2 Toroids can give more current than 1. So by default, the amp is more like a 250wpc amp rather than a 200wpc amp. (Actually it clips at 282 watts into 8 ohms).
What I did not do is increase the voltage by much, If I did that, then heat build-up would have been an issue. So reliability is as default while current drive is increased.
The same is the case with the Adcom 555 and 565. Both have DC rails of 82-0-82 but the 555 has a 675 VA toroidal and makes 200wpc while the 565 has the same rails i.e. 82-0-82 but makes 300 watts, well because it has a 2500VA power supply.
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