Sha2 • 1 super stereo headphone amplifier kit ramsey electronics model no. Sha2 • separate volume, treble, bass, balance and loudness • signal level clipping indicator led • stereo loop-through for multiple feeds with separate controls • cd quality audio • runs on a 9 volt battery or 12 to 20 vdc ex...
Sha2 • 2 partial list of available kits: ramsey transmitter kits • fm10a, fm25b, fm30, fm stereo transmitters • fm100b, fm35 professional fm stereo transmitters • am1, am25 am broadcast band transmitters ramsey receiver kits • fr1 fm broadcast receiver • ar1 aircraft band receiver • sr2 shortwave re...
Sha2 • 3 super stereo headphone amp ramsey publication no. Sha2: manual price only $5.00 table of contents circuit description................................4 “learn as you build”.............................8 parts list..............................................9 parts layout diagram .............
Sha2 • 4 circuit description let’s take a look at the schematic diagram, we will follow through from input to output to get a general idea how this kit works, and why. We will look mainly at the left channel circuitry starting at j1. Items in parentheses , ‘(xx)’, refer to the right channel signal p...
Sha2 • 5 c12(c24) is another coupling capacitor, and it serves the same purpose as c9 at the start of the circuit. This prevents the dc portion of the signal on the output of u2(u4) from being sent to the headphones. The clipping detector circuit the clipping detector circuit watches the headphone o...
Sha2 • 6 impedance makes it possible to connect multiple devices, like the sha2, with high impedance to the output without having any significant effect on the quality of the signal. This is called bridging the output. Wondering what impedance is? If you know about resistance you know, or i’ll tell ...
Sha2 • 7 the power supply vr1, c29 and c28 supply the regulated dc voltage for the circuit. Vr1 regulates the input, which should be around 12vdc input to j5, to a level of 10vdc for use in the unit. Yes the internal supply voltage indicates it is 9vdc and here is the reason why. You will notice tha...
Sha2 • 8 ramsey “learn-as-you-build” assembly strategy be sure to read through all of the steps and check the boxes as you go to be sure you didn't miss any important steps. Although you may be in a hurry to see results, before you switch on the power check all wiring and capacitors for proper orien...
Sha2 • 9 sha2 parts list capacitors 5 10 nf ceramic disc capacitors [marked 103] (c3,13,15,21,25) 2 100nf ceramic disc capacitors [marked 104] (c14,27) 2 100pf ceramic disc capacitors (marked 100, 101, or 101k ) (c11,23) 4 220nf ceramic disc capacitors (marked ) (c6,7,8,26) 2 390nf ceramic disc capa...
Sha2 • 10 sha2 parts layout diagram.
Sha2 • 11 assembly steps you’ve got your parts sorted, your iron is warmed up, so let’s get started. We’ll follow a logical order when installing the parts in your kit. Take your time and be sure to make good, solid solder connections. Save a couple of the longer leads that you snip off the back whe...
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Sha2 • 14 lead is not only shorter than the other, it has a band or stripe running down the body of the part next to the short lead that shows zeros or minus signs. Be sure to install the part so that the positive lead goes into the hole marked with a “+” sign and the negative lead into the other. P...
Sha2 • 15 install c14, 100nf ceramic disc capacitor (marked 104). Install r7, a 2 ohm resistor (red-black-gold). Install c23, 100pf ceramic disc capacitor (marked 100, 100k, or 101). It’s tucked in between u2 and u4. Install c27, 100nf ceramic disc capacitor (marked 104). Install r14, 2 ohms (red-bl...
Sha2 • 16 install r4, another 1 m ohm resistor (brown-black-green). Install c28, 10uf electrolytic capacitor. Remember the polarity yet again. Install c29, 10uf electrolytic capacitor. Placement. Install c9, 10uf electrolytic capacitor. Watch your placement.. Install c2, yup, another pesky 10uf elec...
Sha2 • 17 stories about dpdt switches to bore you with. Back to jacks, install j2 and while you’re at it, let’s install j1 and get it over with. Both are 3.5mm stereo jacks. Now install j5, the 2.1mm power jack. Time to install the 9v battery holder. This is where you’ll need that clipped off lead f...
Sha2 • 18 the battery snap is the last part to be installed. The red lead goes into the hole marked with a “+” sign and the black goes into the “-” hole. You can tin the leads by twisting them together and melting some solder on them or you can simply twist them, put them through the board, and sold...
Sha2 • 19 setup and testing it’s time to apply power to your sha2 and start listening to your line level sources. You need: • an ac adapter or a fresh 9 volt battery • a line level audio source (cd player line out, etc.) • a cable to connect the audio source to the sha2. Either dual rca to 3.5mm ste...
Sha2 • 20 you can set the left and right channels independently of each other. H1 controls the right channel of the stereo output and h2 controls the left channel. Pin 1 on both h1 and h2 is marked by a triangle. By placing a jumper block between pins 1 and 2 of h1 and h2, the buffered output follow...
Sha2 • 21 troubleshooting while we hoped it wouldn’t come to this, it’s possible that your sha2 didn’t work as soon as you applied power. The main thing to remember in a situation like this is . . . Don’t panic! It’s usually something simple and since you built the kit, you know the kit and you’ll f...
Sha2 • 22 if you enjoyed this ramsey product, there are plenty more to choose from in our catalog - write or call today! Conclusion we sincerely hope that you will enjoy the use of this ramsey product. As al- ways, we have tried to compose our manual in the easiest, most “user friendly” format possi...
Sha2 • 23 the ramsey kit warranty please read carefully before calling or writing in about your kit. Most problems can be solved without contacting the factory. Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All ramsey kits will work if assembled...
Sha2 • 24 table of contents circuit description................................4 “learn as you build”.............................8 parts list ..............................................9 parts layout diagram ........................10 assembly steps .................................11 schematic ...
