Monday, November 2, 2020

ADA PTM-1260 The Perfect Dolby Atmos Amplifer

When building a Dolby Atmos 9.1.4 system, the number of amplified channels required grows quickly.  Below is the 9.1.4 design overview from Dolby.


Dolby Atmos 9.1.4 Structure:


That is a lot of channels.  The ADA PTM-1260 allows you to fit all your amplifiers into one rack with the flexibility to support:

  • 6 channels bridged at 265w/ch @ 8 ohms || 390w/ch @ 4 ohms, or
  • 12 channels not bridged at 77w/ch @ 8 ohms || 140w/ch @ 4 ohms, or
  • A combination of those based on the power requirements of your atmos/in ceiling speakers
A Dolby Atmos 9.1.4 system can be supported by two PTM-1260 amplifiers:
  • Amplifier 1, 6 Channels Bridged :  Left, Center, Right, Wide Right, Wide Left, with one bridged channel open
  • Amplifier 2:
    • Bridged: Left Surround, Right Surround, Rear Right, Rear Left
    • Not Bridged:  Front Left/Right Ceiling + Rear Left/Right Ceiling
 

Here is what they look like racked.  While they can hold their own weight with the face, these amplifiers are way too heavy to rack without help.  I installed shelves that can slide out to ease installation and support servicing.  I selected Kendall Howard 20 inch vented sliding shelves.  The rack holes line right up on those shelves with a thin foam spacer under the amp.







Monday, November 25, 2019

PTM-1260 - Another Fan Replacement

Happened to be able to purchase a used ADA PTM-1260 on eBay that was in need of repair.  In addition to a cold solder joint on the 12v trigger, it had a bad fan.  Looks like the design of the PTM-1260 has changed slightly.  This fan was an ETRI 141LV 115v fan.  I pulled that out and replaced with a Papst 4140N -- just because it has been rock solid in my other PTM-1260 amplifiers and is quiet.  In addition to the change of the fan manufacturer, the board layout changed slightly.  I have included photos of the layout and new fan install -- nice and quiet now.







Friday, January 18, 2008

Welcome!

This site is to one of my absolute favorite pieces of audio equipment... my ADA Audio Design Associates PTM-1260 multi channel amplifier. While many pre-amplifiers have come and gone through my systems, this has been the mainstay.  There is not a lot of information on this amplifier, so this appears to be the only fan site.  It is a custom installation product that is meant to be rack mounted. 

This blog describes the amplifier and has my notes on modifying and maintaining the amplifier. Hopefully you can find everything you need to know about maintaining it here.

Here are a couple photos of this beautiful amplifier.













PTM-1260 Specifications


The PTM-1260 amplifier is one of the most flexible and most powerful amplifiers on the market. It is one of the only 12 channel amplifiers that can easily power a whole house audio system or power a home theater. Here are the features:

  • Highest power 12 channel amplifier on the market
  • 12 channels - supports 6 speaker pairs for a multi-room installation. This configuration provides: 75 watts per channel into 8 ohms; 135 watts per channel into 4 ohms
  • 6 bridged channels - each pair of channels can be combined - bridged - with another pair to support 3 speaker pairs for a multi-room installation; or 6 speakers in a home theater installation. This configuration provides: 265 watts per channel into 8 ohms; and close to 400 watts per channel into 4 ohms
  • Independent channel trigger through the 9 pin serial connector
  • 12v trigger on/off
  • Dynamic front panel LED display - displays music level on each channel in a brilliant red
  • Can be rack or shelf mounted
Product Links
Below are some good links for additional PTM-1260 information:
Multizone Amplifier Comparisons:
I have put together quick amplifier comparison. Included in the comparison are the Niles SI-1260, Speakercraft BB-1260, Russound R1250MC, Russound DPA-6.12, AudioControl Model 860 and AudioControl Model 700.

Click on the link below to view the graphic!




Amplifier Face Options:

Audio Design Associates has several options available for face of the amplifier:
  • Rack Mount - this is a solid metal face with a black anodized finish. This face comes with two rack handles also in a black anodized finish. This option allows for easy rack mounting into a 3U rack space. 4 rack holes are available for securing to the rack. Dimensions are 19w x 5 1/4h x 1/8 thick. Cost is roughly $300 and can be ordered directly from ADA.

  • Select Series - this is a solid metal face with a black anodized finish. This face does not come with rack handles, however you can add your rack handles from the rack mount face if you would like. This is the face that I have on my amplifier in the photos in this blog. It provides a nice finish when the amplifier is shelf mounted. Dimensions are 18w x 6h x 1/8 thick. Cost is roughly $300 and can be ordered directly from ADA.

  • Aluminum, Chrome or Brass - This face is the face that you typically see in the magazines. The brass finish was pretty popular in the 90s and early 00s. The most popular now seems to be the chrome finish. It looks fantastic. I have never seen the Aluminum finish. These typically come in the rack style. Cost is very high, so you really gotta want it: $1000.

  • 30th Anniversary Aluminum - I saw this as an option in the 2008 catalog. They don't have a photo in the catalog or on the site. It probably looks amazing. I emailed ADA, and this face will only be sold on new units. You can't buy this face seperately unfortunately :-(

You can install this face yourself if you are comfortable working with electrical equipment. Note that the inside of this has some high voltages. I won't walk through the process to replace one here, but it does require opening the top of the unit, removing the front face which involves around 8 screws, and unscrewing the original rack handles from the inside. Then you put it all back together. Takes about an hour. I recommend buying little black neoprene washers from your local Home Depot to place between your new face and the screws so that you don't scratch it when tightening. The black plastic washers that come with wall mounting screws work perfectly!

Here is a photo of the chrome plate

Connecting RCA Cables:

When I first purchased this amplifier, I had a tough time getting the audio to sound right. A call to ADA support quickly helped me figure out the issue. First, the guys at ADA are fantastic. They are responsive over email or phone, and they treat you like a customer.

So here are the things to keep in mind when connecting your audio cables:

  • This amplifier is super sensitive to the use of directional cables. If you use them make sure that they are installed in the right direction. If you install a cable in the wrong direction, the audio may be distorted, or no sound will be generated. Most cables come with arrows, so just follow the directions.
  • Hum. I found that if the RCA cable is pushed all the way onto the female receptacle, such that the RCA metal cylinder is touching the amp's metal back-plate, that a hum is induced. Just pull the RCA cable a milimeter back and you are all set. This might be due to the fact that the cables are directional. ADA doesn't recommend directional cables.
Replacing the Fan:
This amplifier is cooled with a single fan that pulls cool air in and over a large aluminum heatsink. The fan is a heavy duty, cast aluminum, Papst 4840N axial fan. This fan is from the 4000 series of axial fans, and is the quietest fan available from Papst in the series. Features include:

  • Measurements: 119 x 119 x 38 mm

  • Airflow: 50 CFM

  • Voltage: 115v 50-60Hz

  • Noise: 26 dB(A)

  • Bearings: Sintec sleeve bearings
  • Life: ~57,500 hours / 6 years continuous use
  • Cost: $40 including shipping
  • Vendor: OnlineComponents.com
  • Replacement Time: 1 hour



If this amplifier is used in a wholehouse implementation, the amplifier will most likely run continuously. A home theater would provide much less wear on the fan. My fan began acting funny after about 6 years... right at the life span specified by the manufacturer. It began by sometimes not coming on when the unit was powered up, and then gradually began running more slowly until one day it just wouldn't turn.

Aside from being quiet, the fan is easily replaceable. Here are the steps to replace the fan:
  • Remove the top: There are about 16 small screws that keep the top on. These are easily removed with a philips screwdriver.

  • Remove the fan: There are four screws that hold the fan to the inside of the left wall. Use a 1/8 inch hex key to remove the four screws. The metal fan protector will come off to.

  • Remove Power From the Fan: At the top left corner of the fan is a power connector. The connector is easily removed from the fan by pushing it down so that it disconnects from the two pins on the fan. Take care not to touch any other components within the amplifier.

  • Remove the Ground Cable: Now that the power connector is off, you will see that down below near the base of the fan, is a ground cable. This is held on by a single screw that can be easily reached with a long screw driver. Once that is removed, the fan can come out.

  • Replacement: Now just reverse the steps to put the new fan in.
  • Dust Guard: I tried adding one of those aluminum mesh dust guards but the noise of the air flowing through the mesh was significant.