Related Manuals for DYNACO PAT-4
Summary of Contents for DYNACO PAT-4
- Page 1 PAT-4 PHONO UPGRADE ASSEMBLY MANUAL © 2016 AkitikA, LLC All rights reserved Revision 2p13 January 15, 2015 Page 1 of 23...
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Page 2: Table Of Contents
Figure 7-Both PCBs reassembled onto U brackets, ready for installation (DRD4 kit installed also) ........................12 Figure 8-Changes to grounds for 5 high level input version of PAT-4 ......14 Figure 9-Adding shielded cable as part of the 5 high level input modification ....16 Figure 10-Schematic shows phono preamp with modifications (3 High level and 3 phono level inputs) ........................ -
Page 3: Section 1: About This Manual
This manual gives the information you need to install the phono upgrade to the Dynaco PAT-4 Preamp. Manuals starting from Rev 2p13 cover the Rev B version of the kit, which substitutes a 1K resistor for the original 4K7 R1, instead of a jumper. As of this... -
Page 4: Tools And Supplies You'll Need
Tools and Supplies You’ll Need You’ll need the following tools: 1. flat blade screwdrivers for #4 and #6 screws, #2 Philips head screwdriver 2. needle nose pliers (helpful, but not strictly necessary) 3. pencil type soldering iron of 25 to 50 Watts (no huge honking soldering guns or blowtorches) 4. -
Page 5: Section 2: About The Phono Preamp Upgrade
Section 2: About the Phono Preamp Upgrade Effects of the Modification The phono preamp will be 4 to 8 dB quieter than the stock preamp. Phono High and Phono Cer inputs will no longer be active. You’ll have two more phono inputs because: o The special input will be equalized for phono. -
Page 6: Preparing To Remove The Circuit Boards
Preparing to Remove the Circuit Boards 1. Disconnect the PAT-4 from your music system. 2. Unplug the power cord and allow the preamp to sit for one minute before moving Caution: Be sure that the preamp power is unplugged! 120 VAC can be lethal! 240 VAC can be lethal! 3. -
Page 7: Pc Board Modifications
PC Board Modifications The listed procedure will be repeated for both left and right channel PC boards. In general, you will: Remove the indicated component Clear the solder from the associated PCB mounting holes Install the new component, carefully following the directions, as you’ll mount some of the new components in unconventional ways to generate the upgraded topology of the phono preamp. -
Page 8: Figure 1-Stock Pcb (Before Upgrade)
Figure 1-Stock PCB (before upgrade) Figure 2-Stock PCB (after upgrade) Page 8 of 23... -
Page 9: Figure 3-Detail Of R2-C3-White-Wire Connection
Remove C1 Replace C1 with a 0.33 µF film capacitor (carries the number 334 on the body). Remove C3. Replace C3 with a 1000 µF electrolytic capacitor. Slide a ½” piece of insulation stripped from the supplied black 22 AWG wire over the negative lead of C3. -
Page 10: Figure 4-Preparing C4 For Installation
Remove C7 Nothing goes in its place Remove the jumper Nothing goes in its place. directly below C7 Remove Q1 Replace Q1 by the MPSA18. Match the orientation of the flat to Figure 2. Remove Q2 Replace Q2 with an MPSW45A. -
Page 11: Adding R30 If Your Pcb Doesn't Have A Place For It
Adding R30 if your PCB doesn’t have a place for it Only perform the operations in this section if your PAT-4 is one of the early production models that did not have a place on the PCB for R30. Insert a 48K7 Ohm resistor into the back of the board as shown in Figure 5. Note that two leads fit in the one hole that connects to eyelet 5: C4’s still unsoldered lead, and R30. -
Page 12: Inspection And Preliminary Reassembly
4-40 keps nuts. They have captive lock washers that simplify reassembly. Screw the assembly of PC-boards and U-shaped bracket back into the PAT-4 chassis. Use the original 6-32 screws and the new 6-32 keps nuts (also with captive lock washers). -
Page 13: Final Wiring And Reassembly
Final Wiring and Reassembly Done Done These Steps Are Important! You’ll see that the PEC 555005 attaches to a number of pins around the phono inputs. Cut lead 3 of PEC 555005 near where it attaches to the center conductor of the RCA jack labeled “Phono Low”, leaving the lead as long as possible. -
Page 14: Figure 8-Changes To Grounds For 5 High Level Input Version Of Pat-4
Figure 8-Changes to grounds for 5 high level input version of PAT-4 Page 14 of 23... - Page 15 Untwist this wire from the others, and route it and connect it to eyelet 5 of the REAR PC-16. (On some PAT-4’s, it may be so short that you’ll have to replace this wire with a longer wire.) Desolder (or clip) the wire that connects to back-panel terminal 12 (this ...
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Page 16: Figure 9-Adding Shielded Cable As Part Of The 5 High Level Input Modification
Figure 9-Adding shielded cable as part of the 5 high level input modification Page 16 of 23... -
Page 17: Final Sanity Checks
Final Sanity Checks Here are a few last tests before you reconnect your PAT-4 to your music system. With the top still off, plug in the AC mains. Turn on the power switch. Set your meter to DC volts. Connect one lead of the meter to ground. -
Page 18: Appendix 2: First Class De-Soldering
solder. Remove the soldering iron, but let the toothpick remain in the hole until the solder has solidified. Now remove the toothpick. There should be a hole through the solder sufficiently large to allow you to insert the component lead or wire. Sometimes, a bit of the toothpick will break off in the hole. -
Page 19: Schematics
Schematics Figure 10-Schematic shows phono preamp with modifications (3 High level and 3 phono level inputs) Page 19 of 23... -
Page 20: Figure 11-Schematic When Modified For 1 Phono And 5 High Level Inputs
Figure 11-Schematic when modified for 1 phono and 5 high level inputs Page 20 of 23... -
Page 21: Record Playing Reminders
The ground wire between the turntable and the ground screw on the back-panel of the PAT-4 preamp must be connected to minimize the hum. Usually, that wire runs loosely along with the RCA cords. Check your tracking force and anti-skating force. Re-balance your tone arm if it has been a while. -
Page 22: Appendix 3 - Preparing A Shielded Cable End
Appendix 3 - Preparing a Shielded Cable End This section tells how to prepare the ends of the shielded cable. This process will be repeated four times, at both ends of both input cables (although the cables will have different overall lengths). 1. - Page 23 5. Separate and twist the drain wire. 6. Peel back and remove the foil. Remove the plastic wrap from the red and black wires. The drain (bare wire), red, and black wires are exposed now that gray insulating jacket, foil shield, and plastic over-wrap have been removed. 7.