Do I need a Preamp or a source selector, Here is what I want to accomplish, Wired the house up with in wall volume controls and speakers through out. I have a 12 channel amp and a another straight 200 what Samson amp. I would like to hook my Turntable, Cd player, Tape deck and Computer up to these amps and be able to select between these sources. I really do not need a volume control but would like an FM tuner.
What should I be searching for, I have looked at a couple of Adcom preamps on Ebay.... Any sugestions
Buffers or gain stages that can drive the long, around the house, cables.
Low output impedance and good current capability. I'd suggest 50r and 20mApk as a start point. Almost any competently designed buffer can achieve this.
If some of your sources have noticeably lower output voltage, then I'd suggest that a gain stage be used to bring all the sources up to similar output levels. This then means that the cables are handling the same levels and any amps you hook up also get fed with similar levels irrespective of what is selected.
A B1 does not come into this category. It has a deliberately low current capability of ~9mApk, that is perfectly adequate for shorter in room cable driving.
Low output impedance and good current capability. I'd suggest 50r and 20mApk as a start point. Almost any competently designed buffer can achieve this.
If some of your sources have noticeably lower output voltage, then I'd suggest that a gain stage be used to bring all the sources up to similar output levels. This then means that the cables are handling the same levels and any amps you hook up also get fed with similar levels irrespective of what is selected.
A B1 does not come into this category. It has a deliberately low current capability of ~9mApk, that is perfectly adequate for shorter in room cable driving.
If your turntable has a magnetic phono cartridge instead of electrostatic, then you need a disco mixer. All inputs on at once, put in the media (or turn on the radio) the output comes out. Many have a headphone jack that will put out significant current.
Peavey makes one that you can get schematics for. They sell parts to individuals, too, in case the used one you buy has bad slider pots (somewhat inevitable). The Herald RA88a I bought for $15 was easily modifyable to mid fidelity with better op amps (than 4558) and an external power supply (to cut the hum), but I've probably got the only one in the US. It had great slider pots! Nice SS front panel, and compact. Numark mixers have SMD parts and ribbon cables, not very repairable or upgradeable to mid-fi. No schematics available, either. Behringer doesn't give away schematics, either.
Or you can buy a preamp, and make a separate stop to switch the input everytime you change. Don't buy a tube one like my PAS2, they have 250k output impedance and can just about drive 6' of RCA jack cable.
Peavey makes one that you can get schematics for. They sell parts to individuals, too, in case the used one you buy has bad slider pots (somewhat inevitable). The Herald RA88a I bought for $15 was easily modifyable to mid fidelity with better op amps (than 4558) and an external power supply (to cut the hum), but I've probably got the only one in the US. It had great slider pots! Nice SS front panel, and compact. Numark mixers have SMD parts and ribbon cables, not very repairable or upgradeable to mid-fi. No schematics available, either. Behringer doesn't give away schematics, either.
Or you can buy a preamp, and make a separate stop to switch the input everytime you change. Don't buy a tube one like my PAS2, they have 250k output impedance and can just about drive 6' of RCA jack cable.
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