Ramsey Electronics SHA2 manual

SHA2 • 1 SUPER STEREO HEADPHONE AMPLIFIER KIT Ramsey Electronics Model No. SHA2 • Separate volume, treble, bass, balanc e 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 V DC external po wer Want to listen to your[...]

SHA2 • 2 PARTIAL LIST OF AVAILABLE KITS: RAMSEY TRANSMITTER KITS • FM10A, FM25B, FM30, FM Stereo Transmitters • FM100B, FM35 Professio nal FM Stereo Transmitters • AM1, AM25 A M Broadcast Band Trans mitters RAMSEY RECEIVER KITS • FR1 FM Broadcast Rec eiver • AR1 Aircraft Band Recei ver • SR2 Shortwave Recei ver • SC1 Shortwave Con v[...]

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 ........................ 10 Assembly Steps ......[...]

SHA2 • 4 CIRCUIT DESCRIPTION Let’s take a look at the schematic diagram, we will follow through f rom 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 parenthe ses , ‘(xx)’, refer to the right channel sig nal path. Standard configuration settings wi[...]

SHA2 • 5 C12(C24) is another co upling capacitor, and it serves the same purpose as C9 at the start of the circuit. This pr events 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 circu it watches the headphon e output signal level and flashes an LED when t[...]

SHA2 • 6 impedance makes it possible to conn ect multiple devices, like the SHA2, with high impedance to the output without having any signi ficant effect on the quality of the signal. This is called bridging the output. Wondering what impedance is? If you know about resistance you kno w, or I’ll tell you, resistance is a measurement, in ohms, [...]

SHA2 • 7 The power supply VR1, C29 and C28 supply the regul ated DC voltage for the circuit. VR1 regulates the input, which should be arou nd 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 that diode D1 is connected between VR1 and the p[...]

SHA2 • 8 RAMSEY “LEARN-AS-YO U-BUILD” ASSEMBLY STRATEGY Be sure to read through all of the steps and che ck the boxes as you go to be sure you didn't miss any important st eps. Although you may be in a hurry to see results, before you switch on the power check all wiring and ca pacitors for proper orientation. Also check the boa rd for a[...]

SHA2 • 9 SHA2 PARTS LIST CAPACITORS  5 10 nF ceramic disc capacitors [ma rked 103] (C3,13,15,21,25)  2 100nF ceramic disc capacit ors [marked 104] (C1 4,27)  2 100pF ceramic disc capacit ors (marked 100, 101, or 101K ) (C11,23)  4 220nF ceramic disc capacit ors (marked ) (C6,7,8,26)  2 390nF ceramic disc capacit ors(C19,20)  14 [...]

SHA2 • 10 SHA2 PARTS LAYOUT D IAGRAM[...]

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 you r kit. Take your time and be sure to make good, solid sold er connections. Save a couple of the longer leads that you sni p off the back when trimming. You need one of them for a [...]

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SHA2 • 14 lead is not only shorter than the other, it has a band o r stripe running down the body of the part next to the s hort 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 ne gative lead into the other. Push the part down until it sits on the bo[...]

SHA2 • 15  Install C14, 100nF ceramic disc capacitor (ma rked 104).  Install R7, a 2 ohm resistor (re d-black-gold).  Install C23, 100pF ceramic disc capacitor (ma rked 100, 100K, or 101). It’s tucked in between U2 and U4.  Install C27, 100nF ceramic disc capacitor (ma rked 104).  Install R14, 2 ohms (red-black-g old).  Instal[...]

SHA2 • 16  Install R4, another 1 M ohm resistor (b rown-black-green).  Install C28, 10uF electrolytic capa citor. Remember the polarity yet again.  Install C29, 10uF electrolytic capa citor. Placement.  Install C9, 10uF electrolytic ca pacitor. Watch your placement..  Install C2, yup, another pesky 10uF electrolytic. The lead with [...]

SHA2 • 17 stories about DPDT swit ches to bore you with.  Back to jacks, install J2 an d 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 from the beginning of your co[...]

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 bla ck goes into the “-” hole. You can tin the leads by twisting them together and melting some sol der on them or you can simply twist them, put them through the b oard, and solder them. It’s up to you. Just d[...]

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 stereo or 3.5mm stereo to 3.5mm stereo, dep[...]

SHA2 • 20 You can set the left and right channels indep endently 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 blo ck between pins 1 and 2 of H1 and H2, the buffered output follows the input exactly. Whatever you have coming [...]

SHA2 • 21 TROUBLESHOOTING While we hoped it wouldn’t come to th is, it’s possible that your SHA2 didn’t work as soon as you applied power. Th e main thing to remember in a situation like this is . . . don’t panic! It’s usually something simp le and since you built the kit, you know the kit and you’ll find it if you look carefully. Jus[...]

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 produ ct. As al- ways, we have tried to compose our man ual in the easiest, most “user friendly” format possible. As our customers, we value your opini[...]

SHA2 • 23 The Ramsey Kit Warran ty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solved without contacting the fa ctory. Notice that t his is not a " fine print" w arranty. We want y ou to understand y our rights and ours too! All Ramsey kits w ill work if assemble d properly . The very fact tha[...]

SHA2 • 24 TABLE OF CONTENTS Circuit Description ................................ 4 “Learn as you Build” ............................. 8 Parts List .............................................. 9 Parts Layout Diagram ........................ 10 Assembly Steps ................................. 11 Schematic .....................................[...]