Archive for October 2023

3-in-1 Can Capacitor Kit

Replaces multi-section cans with 1.5 inch CTC mounting holes. Fits three 5 mm or 7.5 mm lead spacing, 12.5 mm diameter capacitors

Click the link below to download the installation guide

3-in-1-CGDownload

This kit is intended as an easy way to mount new radial electrolytic capacitors when replacing 1 inch diameter multi section can capacitors with 1.5 inch mounting hole spacing CTC. This design was modeled after an Astron A-25-65 can. These were often used in vintage radio equipment.

Up to three different caps can be installed, and they all share a common lead located in the center. The center common lead has a trace connecting it to one of the mounting holes, making it convenient to tie to chassis ground; if you need to isolate this board from chassis ground, take a look at our insulation kit. The spacer board sits between the new caps and mounting board and adds clearance between the turrets and cans of the caps. Four turrets provide a robust post for wires and other components to attach to when installing.

If you use a positive-common configuration, be wary that the cans of electrolytic caps are often tied to the negative lead (cathode), but not always. Thus, voltages may exist between the cans depending on the circuit, so space them apart as needed.

Based on IPC-2221B guidelines, this board is not to be used in circuits that may see peak voltages above 450 V assuming a typical negative-common configuration.

Specifications:

  • Board material: FR-4 Kingboard TG150 (CTI >175)
  • Board finish: HASL (lead-free solder), green solder mask
  • Copper thickness: 2 oz.
  • Screw hole spacing: 37.79mm center-to-center (Approx. 1.5 inches)
  • Screw hole size: 3.8mm (#6-32 fits slightly loose to allow adjustment)
  • Wiring/turret hole size: 2.4mm
  • Width: 47.59mm
  • Length: 34.14mm
  • Board thickness: 1.6mm
  • Height from surface of mounting board to top of a turret: 7mm
  • Max capacitor diameter: 12.5mm
  • Capacitor lead spacing: 5mm and 7.5mm
  • Insulator board diameter: 29mm
  • Insulator board thickness: 2mm
  • Insulator board hole size: 4.2mm for turrets, 2.6mm for capacitor leads
  • Diameter of turret’s hole: 1.63mm

Note: Dimensions are nominal values. Outline dimensions may vary by ±0.15mm, and hole sizes by ±0.076mm.

4-in-1 Can Capacitor Kit

Replaces multi-section cans with 46 mm CTC mounting holes. Fits four 5 mm lead spacing, 12.5 mm diameter capacitors

Click the link below to download the installation guide

4-in-1-CGDownload
  • Multi section can capacitor replacement

This kit is intended as an easy way to replace old multi-section can capacitors around 1-3/8″ diameter (approx. 35 mm) with 46 mm CTC mounting hole spacing. These cans were often used in vintage audio and radio equipment, such as McIntosh, Marantz, Heathkit, and Dynaco.

The capacitor board fits up to four 5 mm lead spacing, 12.5 mm diameter radial capacitors. An alternate version of this kit designed for larger 7.5 mm lead spacing, 16 mm diameter capacitors is also available.

The negative leads of all capacitors are connected to a thick outer copper ring and two plated mounting holes. This means the negatives will be tied to chassis ground by default. If you need to isolate this board from chassis, take a look at our isolation kit.

Includes one capacitor mounting board, one spacer board, 5 wiring turrets, a mounting hardware kit, and a link to installation instructions. Capacitors are not included. In order to save on paper and toner, we are now including a link to a PDF copy of the installation guide. If you would prefer a hard copy, please let us know and we’d be happy to accommodate.

Based on the IPC-2221B standard, this kit is not to be installed in circuits that will see peak voltages greater than 600 V.

Specifications:

  • Board material: FR-4 Kingboard KB-6165F (TG150, CTI >175)
  • Board finish: HASL (Lead-free solder), matte black solder mask
  • Copper thickness: 2 oz.
  • Screw hole spacing: 45.95 mm center-to-center
  • Screw hole size: 3.5 mm (#6-32 machine screw fits snug)
  • Wiring/turret hole size: 2.4 mm
  • Width: 55.39 mm
  • Length: 37.96 mm
  • Board thickness: 1.6 mm
  • Height from surface of mounting board to top of a turret: 7 mm
  • Spacer board diameter: 27 mm
  • Spacer board thickness: 2.0 mm
  • Capacitor lead spacing: 5 mm
  • Max capacitor diameter: About 12.5 mm
  • Capacitor lead hole size: 1.2 mm
  • Diameter of turret’s hole: 1.63 mm

Note: Dimensions are nominal values. Outline dimensions may vary by ±0.15 mm, and hole sizes by ±0.076 mm

Ohm’s Law/Joule’s Law PCB Wheel

  • Ohm's Law Wheel Ornament

This is a 10 cm diameter wheel made of FR-4 (typical PCB material) that combines Ohm’s Law and Joule’s Law into one handy reference chart. To calculate one of the inner quantities, use two known quantities and the appropriate outer expression. Example: the power dissipated by a 1 kOhm resistor with 100 mA flowing through it is P = I2R = 0.12 A * 1000 Ohm = 10 W. This particular relationship is called Joule heating or Joule’s first law.

The reverse side features the likenesses of Georg Simon Ohm and James Prescott Joule. Electrical engineers, technicians, and hobbyists alike utilize these laws on a daily basis.

Available in green/gold, black/gold, red/gold, and laser etched wood. Note: The wood version does not have the portrait of Ohm and Joule on the back.

“If I have seen further, it is by standing on the shoulders of giants.”

— Excerpt from a 1675 letter from Sir Isaac Newton to Robert Hooke

Specifications:

  • 1.6 mm thick FR-4, immersion gold finish (wood version is 5 mm thick)
  • One hole provided for mounting or hanging

If you know a friend or family member who would appreciate a PCB medallion with custom artwork on it as a gift (e.g. a picture of a pet, loved one, etc.), we’d love to help you get some manufactured. They also make great Christmas ornaments. Please contact “parts (at) proaudioe.com” for more information. We can order as few as 5 PCBs.

MLD7020 Line Memory Replacement

MN4760S-PAE

  • McIntosh MLD7020 Laser Disc Player MN4760S

This is an FPGA implementation of the MN4760S line memory used in the time base corrector (TBC) sections of some LaserDisc players. This board was designed specifically for an MLD7020 with a dead line memory, breathing some new life into a unit that would have otherwise been a paperweight due to the original part no longer being manufactured.

This board is not available for order at this time. Please contact “parts (at) proaudioe.com” if you would like additional information.

MAC4100 RCA Jack Replacement Kit

MAC4100RCA

Click here to order

Click here to download the installation guide

  • McIntosh MAC4100 RCA Jacks

This kit is designed to replace the original riveted RCA jacks used on the back of McIntosh MAC4100 receivers. A custom RCA mounting board re-uses the original rivet holes for attaching to the back panel and provides plated holes for soldering the input/output shielded cables. The mounting board uses 2 ounce copper and wide traces to connect each RCA jack to their respective solder pads, and the star ground arrangement of the original wiring scheme is maintained. A matte black cover plate is included for replacing the original black shrouds around the RCA jacks.

Please note that the installation process for this kit is fairly complex and will involve drilling out the original RCA rivets, soldering the new RCA jacks to the mounting board, stripping and soldering each shielded cable to the new board, and mounting the new board in place. We recommend testing your unit before installation to ensure everything is working as expected, and then taking plenty of pictures throughout the process to use as reference.

Note: The included black machine screws will be slightly shorter than those in the listing photos to avoid having extra thread length sticking off of the back.

Parts Included

  • One RCA mounting board
  • One matte black RCA cover plate
  • 12 white, 10 red RCA connectors
  • Wire jumpers
  • 10nF/250V C0G phono ground capacitor
  • Mounting hardware kit
  • Installation guide

Additional Details

  • Connection of each group of RCA jacks to the star ground is facilitated via wire jumpers. The mounting board comes with these jumpers pre-installed in the most common configuration, but depending on your unit, you may need to add or remove a jumper. This is documented in the included installation guide
  • The 10nF ceramic capacitor connecting the phono shields to chassis ground also comes pre-installed on the mounting board, eliminating the need to re-use the original

MC2500 Replacement Power Guard Indicator PCB

PAE-045622

  • McIntosh 045622 MC2500 Power Guard Indicator board

This is a replacement power guard display PCB for McIntosh MC2500 amplifiers. This board is used to mount four bi-pin incandescent lamps which indicate the power guard status for both channels of the MC2500.

Includes one unpopulated PCB and one 5 pin right angle Molex connector. Lamps are not included. Boards may have minor cosmetic surface defects, but this will not impact their functionality.

The hole sizes for the lamps were increased to accommodate PC pin sockets (not included) for simplifying future lamp replacement. If you have LED replacements for 7382 lamps that are designed to be powered with AC (11.2 VAC is typical according to the MC2500 schematic), they should also work just as well on this board.

Specifications:

  • Board material: FR-4
  • Board thickness: 1.6 mm
  • Copper thickness: 1 oz., traces duplicated on both sides

MC2100, MC2105, MC2300 Can Capacitor Replacement Kit

066-095-PAE

Click here to order

Click here to download the installation guide

  • McIntosh MC2100 MC2105 MC2300 Capacitor Kit

This is a replacement kit for the GE multi-section can capacitors used inside the McIntosh MC2100, MC2105, and MC2300 power amplifiers. These cans were stamped with McIntosh part number 066-095. Other models may also use this can. High quality, genuine Nichicon capacitors rated for operation up to 105°C are used to ensure a long operational lifespan, and a custom PCB with thick 2 oz. copper provides a robust and elegant mounting solution. Four wiring turrets facilitate the connections to each of the four caps. No more gutting the old cans and sticking new caps inside!

Includes four Nichicon capacitors, one cap mounting PCB, one spacer PCB, a hardware kit, and a thorough step-by-step installation guide.

Installing this kit will require soldering, drilling out the original can’s mounting rivets, and stripping/attaching wires in a tight space. If you do not have prior experience safely testing and repairing amplifiers at the component level, please have a qualified professional install this kit in your unit.

The following capacitor values are included:

  • 82uF 200V (Replaces 80uF 200V)
  • 82uF 200V (Replaces 80uF 200V)
  • 150uF 160V (Replaces 150uF 150V)
  • 56uF 160V (Replaces 50uF 150V)

Note: The capacitor symbols (square, triangle, half-circle, dash) on the cap PCB were arranged based on the orientation of the original can in the MC2300. Other models, such as the MC2100, typically had the cans oriented differently, meaning the position of the symbols on this board may not align with your original installation.

MC2100, MC2105, MC2300 Input Preamp Board

128-165-PAE

Click here to order: Assembled, PCB Only

Click here to download the installation guide: Assembled, PCB Only

  • McIntosh 128-165 MC2100 MC2105 MC2300 Input Preamp Board

This is a new-production input preamp board for the McIntosh MC2100, MC2105, and MC2300 power amplifiers. This board follows the original component layout closely, and no changes were made to the original circuit design. Available assembled and tested, or as an unpopulated PCB.

The new PCB is double-sided and uses 2-ounce copper, plated through-holes, an immersion gold finish, and matte black soldermask. Silkscreen reference designators and symbols are provided on both sides. Robust wiring turrets replace the original hollow posts that cables solder to. All component footprints are sized to fit the original parts. In addition, all axial electrolytic capacitors have footprints for radial parts of various sizes, both input film caps support two different lead spacings, and both electrolytic output caps can be substituted with film caps of the appropriate physical size. A capacitor sizing guide is included with unpopulated kits.

Assembled boards are built using high quality components, including Vishay MRS25 series low noise metal film resistors (1% tolerance, 600 mW, 50 ppm TCR), Nichicon electrolytic capacitors (UPM series for supply filters, UKZ for audio stages), WIMA film capacitors, and new transistors. All assembled boards are burn-in tested for 24 hours and run through an Audio Precision analyzer to confirm that they meet the performance specifications listed below.

Parts Included (Assembled Board)

  • Assembled and tested MC2100/2105/2300 input preamp board
  • Anti-static bag for storing your original input board
  • Two 22 kOhm resistors for MC2300’s below S/N 4Y426
  • Installation guide with redrawn schematic, board layout, and parts list

Parts Included (Unpopulated PCB)

  • Unpopulated MC2100/2105/2300 input preamp PCB
  • 16 wiring turrets (one extra)
  • Anti-static bag for storing your original input board
  • Resistor lead forming tool
  • Installation guide with redrawn schematic, board layout, and parts list

Typical Performance

Typical performance of both channels (Audio Precision analyzer, 2 Vrms output from DUT):

  • Gain: 20.83 dB @ 1 kHz
  • Frequency response: +0.01 dB, -0.25 dB from 20 Hz to 20 KHz
  • Signal to noise ratio: -97.1 dB below 2 V output (20 Hz – 22 KHz analyzer fltr, unwtd)
  • THD+N: Less than 0.007% from 20 Hz – 20 KHz (no analyzer fltr, unwtd)
  • IMD: Less than 0.005% (DIN 250 Hz/8 KHz 4:1)

Note that these specifications apply to the preamp board by itself and do not reflect the overall performance of your McIntosh amplifier. We have tested an original MC2100 input board in the same manner and found that this new board slightly exceeds the performance of the original.

We recommend testing your unit first to ensure it is working properly. If you are repairing your unit, please make sure your symptoms are originating from the preamp board before you replace it. Replacing this board will not resolve problems present in the rest of the unit, such as the power supply or amplifier sections. If you have not replaced the original multi-section can capacitor in your unit’s power supply, we recommend doing so; we offer a replacement capacitor kit with a custom designed PCB for this task.

Please do not attempt to install these boards if you are not thoroughly familiar with safely diagnosing, repairing, and testing amplifiers at the component level with test equipment (signal generator, oscilloscope, load, etc.) and a current-limited power supply.

MC2100, MC2105, MC2300 New Production Driver Boards (Unpopulated)

128-077-PAE

Click the link below to download the installation guide

128-077-PAEDownload

March 2024: These boards are currently out of stock, however we are working on a revision that will use all modern-production semiconductors and an improved circuit design.

These PCBs are intended to replace damaged driver boards in the McIntosh MC2300 amplifier. The PCB itself was also used in other models such as the MC2100 and late-revision MC2105 units, and the new board should work in these models with some component changes. Bear in mind that the silkscreen reference designators/symbols are based on the MC2300 schematic, which largely matches the schematic of late-revision MC2105 units, but does not match the schematic of the MC2100. Early revision MC2105 units (s/n 10M01 to 26M07) used a slightly different PCB with multiple circuit and layout changes that would require modifications to the board to implement.

Includes two unpopulated PCBs, four TO-39 spacers, and a thorough install guide with re-drawn schematic, board layout, and parts list.

Please do not attempt to populate and install these boards if you are not thoroughly familiar with safely diagnosing, repairing, and testing amplifiers at the component level with test equipment (signal generator, oscilloscope, load, etc.) and a current-limited power supply.

Here are the main differences between this board and the original:

  • Plated through-holes, wider traces, 2 oz. copper with ENIG (gold) finish and hard-gold plated fingers (better long-term repairability)
  • Silkscreen with reference designators and symbols based on the MC2300 schematic
  • Footprint for the TO-66 (“football” shaped) transistor Q105/106 has pads for substituting it with a TO-220, TO-126, or similar package transistor
  • All original wire jumpers (driver collectors and feedback line) are implemented on the board as traces
  • A footprint is provided for the compensation cap that was put in parallel across the feedback resistor in some revisions (labeled C123/124*), as well as the resistor across the driver input (R175/176)
  • Two different lead spacings are provided for the ceramic disc cap footprints
  • Diode footprints use square pads for the negative terminals and polarized electrolytic capacitors use square pads for the positive terminals
  • Chamfered board edge around the fingers
  • Footprint for axial electrolytic capacitor C121/122 is a bit shorter than the original; please use axial caps around 25mm in length or less. C101/102 is the same length as the original; use axial caps 23mm in length or less.

Specifications:

  • Board material: FR-4 Kingboard KB-6160 (TG130, >175 CTI)
  • Copper thickness: 2 oz.
  • Board finish: ENIG (immersion gold), hard-hold plated fingers, glossy green solder mask
  • Width: 127.45 mm
  • Length: 105.10 mm
  • Thickness: 1.6 mm

Other Notes:

  • The PCB follows the general layout of the original, and no changes were made to the schematic, but it is not an exact replica. The parasitic elements of the board itself (inductance, capacitance, resistance) will thus be slightly different from the original board, and you may find that the values of the compensation capacitors need to be slightly adjusted for good stability. Substituting semiconductors may also require changes to the circuit and should be done with caution.
  • C101/102 on the silkscreen was drawn as a nonpolar cap, but polarized caps are typically used here. The positive terminal is the pad closest to the edge of the board.
  • The symbol for D103/104 bias diode was drawn as a Zener to indicate that it is not an “ordinary” diode, however it is not a Zener; it is a stabistor/forward reference diode with a typical forward voltage of around 1.4V (see service manual/semiconductor datasheet).
  • If using a TO-66 device for Q105/106, take care when installing the heatsink because the base/emitter leads have small pads on the top of the board that could touch the heatsink (i.e. collector) due to the size of the mounting holes. Using short standoffs, fish paper, or a TO-66 insulator underneath can help here.
  • The silkscreen reference designators follow a L/R pattern, so transistor Q105/106 is Q105 on the left channel and Q106 on the right channel.