can i use Seperate Power Transformers for the Individual Parts and still have everything work in sync?
info on Stereo 80
Yes, you can.
The preamp can actually be cut off from the amp board and operate on a separate power transformer.
The preamp has a spot for it's own diodes,D4, for rectification from a single secondary ac transformer like a wall wart (see pic). However, it must be an AC output! I'd say 12vac minimum 24vac max
(You can always crack it open and bypass the diodes.)
I have operated the amp off a single secondary, the top wattage performance was weak! but doable in an office situation. There are some 24v 40va units out there for surplus/ new.
I also floated the ground, and the amp worked. It made a virtual ground with the power resistors. Not recommended.
Yes, you can.
The preamp can actually be cut off from the amp board and operate on a separate power transformer.
The preamp has a spot for it's own diodes,D4, for rectification from a single secondary ac transformer like a wall wart (see pic). However, it must be an AC output! I'd say 12vac minimum 24vac max
(You can always crack it open and bypass the diodes.)
I have operated the amp off a single secondary, the top wattage performance was weak! but doable in an office situation. There are some 24v 40va units out there for surplus/ new.
I also floated the ground, and the amp worked. It made a virtual ground with the power resistors. Not recommended.
Attachments
i notice on the specs of Power amp kits they will have a Voltage required to run them Properly (something like 24-0-24)
would you use a Transformer that Totals at 24 Volts (12-0-12) or one that is 48 Volts (24-0-24)
the Zero is Ground right?
Funny you should bring this up. I'm in the beginning stages of designing such a system for my garage/workshop area. The heart of the system will be a slightly "used" car stereo. They're pretty good these days and include such niceties as CD/MP3/WMA players and radio presets. I'll probably use a circuit from Rob Elliot or one of the "chip-amp's" for output power. I'll probably use one of those 12-volt gel-cells for memory backup. (Like burglar alarms use.)
Part of my goal is to incorporate it into a nice case such that it appears like a "vintage" stereo system. I'll let you know how she turns out.
Part of my goal is to incorporate it into a nice case such that it appears like a "vintage" stereo system. I'll let you know how she turns out.
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Artie-
Head units today usually have a pretty good amp section built in. Some do put out a legitimate 25x4 RMS and that would be loud on 4 high efficiency speakers in a shop...
Although nothing wrong with going bigger.. 🙂
Head units today usually have a pretty good amp section built in. Some do put out a legitimate 25x4 RMS and that would be loud on 4 high efficiency speakers in a shop...
Although nothing wrong with going bigger.. 🙂
For being compact I dont think you can get better than the LM3886 chips. Compact, quite efficient, and a good sound. I have some running from the transformer from an old Technics ZU-55 which produces 38-0-38 rails, a bit high but they can take it. I dont use 4 ohm speakers.
stereo 80 xformer
The Stereo 80 kit use a 21-0-21 vac,, that turns to +/-31vDC. This voltage is good for 4...6..8 ohms.
It can accept 25-0-25 vac (for +/- 37vdc), and perhaps more (I'll be testing the break/ smoke point soon ~😉. That voltage is better for 6..8 ohms.
The LM4766 chip preforms quite well compare to LM3886, better yet, it is stereo. The whole stuffed power supply and amp section is 1.3 x 3 x 5.5 inches. If not enough wattage, use 2 (dual mono) and config in parallel or bridge mode.
// Artie
I had a car stereo pushing through a old linear amp in my garage. It was a clean 20w/ch chipamp type running off a 1st gen switching pwr supply. It was quite effective!
I recently upgraded it to 4ch x 30watts. Now in the Ford ranger!
The Stereo 80 kit use a 21-0-21 vac,, that turns to +/-31vDC. This voltage is good for 4...6..8 ohms.
It can accept 25-0-25 vac (for +/- 37vdc), and perhaps more (I'll be testing the break/ smoke point soon ~😉. That voltage is better for 6..8 ohms.
The LM4766 chip preforms quite well compare to LM3886, better yet, it is stereo. The whole stuffed power supply and amp section is 1.3 x 3 x 5.5 inches. If not enough wattage, use 2 (dual mono) and config in parallel or bridge mode.
// Artie
I had a car stereo pushing through a old linear amp in my garage. It was a clean 20w/ch chipamp type running off a 1st gen switching pwr supply. It was quite effective!
I recently upgraded it to 4ch x 30watts. Now in the Ford ranger!
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the Sony 35 Watt Plate Amp i had has one of those LM3886TF's in it...
it still works so i could reuse it...though id much rather use a Fresh New one.
besides a Power Supply what else does an Amp need to sound half Decent?
What do those 11 Pins on the LM3886 Do? (Individual Function)
if i do decide to DIY the Amp (not a Kit) what are some other Transistors that are Reccomended?
True, but I already have a Marantz, Nakamichi, and Harman Kardon head units that don't have built-in amps. Unfortunately, all three of these are older cassette versions. I'd have to do some mods to have CD/MP3 capability. But . . . they'ld look cool. 😛
I've had the Nak and HK head ends but never a Marantz mobile unit. You sure it's Marantz and not McIntosh?
Nak made a "pre-amp only" car unit some time ago.. I would love to see something similar these days for USB, MP3 and ipod switching and control.
ok...an idea here...
is it Possible to Use a Hard Drive independent of a Computer to store all major Functions and Media?
(Thinking Outside the Box)
is it Possible to Use a Hard Drive independent of a Computer to store all major Functions and Media?
(Thinking Outside the Box)
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