Originally Posted by dgolombowski
I don't understand the attitude. I have previously complimented you on this modification as well as your detailed instructions. The mod performed as advertised and I was grateful for your help. Unfortunately in my case it I apparently needed the full speed of the fan to keep the internals cooled. (I also have twin fans running directly below the SX3200 in a Middle Atlantic mount) I did extensive testing before going back to the OEM configuration. My setup may be unique (6 ft. tall completely enclosed rack with a glass door in the home theater side. The cabinet extends into an adjacent utility room. The cabinet is 30" deep and has two fans on each side and a three fan panel on the top of the cabinet.) but you cannot dispute the fact that returning the fans to full speed cured my issue. I am using this amp of drive a pair of SVS PC-Ultra subs.
You seem to have taken my input personally and you should not. In most scenarios your mod will likely work great but it did not work for me. After all the whole idea of this forum is to share our experiences.
There is not issue, Try concentrating on the message I gave you. My post simply says that you must have created a situation which for whatever reason compromises air flow by being in a very enclosed situation. Series wiring is not your problem, inadequate air flow is.
You never answered both my questions on the ohm loads you are driving. If one is driving two ohm loads or four ohm loads stereo, obviously your amps will generate more heat. So my second message was also part of the conditions you put your amplifiers in, which is requiring full blown fan operation, in your case
The amps are two speed fans (according to the manual), and I have never seen the second speed. Seeing as you managed to go to temperature protection for some reason, I was curious to see if yours went into the second speed.
Other interesting info would be how long it took for you amps to go into temp protection under the conditions you are currently using. As i show, my amplifiers are somewhat closed in, as the cabinets are closed back. The air gets pulled out the back of the amplifier and then gets pushed back to the front via hitting the back of the cabinet and then flowing out the two inch spaces on each side to the front. This in itself is an airflow restriction on my part that has no effect on adequate air flow in my case.
Note the SAmson version of the HPA amplifiers have very thick fan filter at the front. I have removed those filters. They are very restrictive of air flow. I replaced mine with regular punched hole grates, to match the rest of my system. So if airflow is an issue at slower fan speeds you may wish to to without the filter.
The fans in the samson are Jamicon 24 volt as in all HPA series amplifiers. When you turn the amplifiers on with the fans in series each fan will get 7 volts of power. With the fans at normal SPEED 1, the fans will get 14 volts each, not 24, with the fans wired normally. They are hooked up to a 24 volt power supply, so I imagine the other 10 volts kicks in at the SECOND speed, that I have never seen!!!. HAVE YOU!?
As I have further advised, the LM2596 method can reduce voltage to the fans, and the speed can be adjusted more. So if the fans are too noisy for you, (note the fans on these units are on the quiet side of pro amps to begin with), you can try the LM2596 method. That method will allow full adjustment of each fan
from zero to 14 full volts at the start speed. In series you are fixed at 7 volts per fan. The Lm2596 will let you go to 9 10 11 12 13 volts, Allowing a more relaxed fan speed reduction, if your situation requires it. Obviously it does.
The cerwin vega cv 2800 units which are the same as the samson part for part, have no restrictive filters in front. The simple removal of the filter changes air flow considerably, but not if you manage to get your rack handles off, and shut the front door while your amps are running LOL. I guess when you series wired your fans you forgot to check to see if the handles came off easy on the inside, hence you asked me if I knew.
All my amplifiers are 8 ohm stereo loaded, or 4 ohm stereo loaded via Bridge Mode. So in my favor of course is very easy amplifier loading as 8 ohm bridge loading,(4 ohm stereo equivalent), is actually less taxing on the amplifiers as you get 3 to 4 times power at half the rail voltages. All my amps run in 8 ohm stereo and 8 ohm bridge.
With all the 2 ohm loaders on AVS. I am surprised many more do not blow there amps, especially after reducing air flow. Lots of behringer ep 2500 and 4000s blown, and I see people modding the fans and 4 ohm bridge loading like crazy. ( I imagine most are not running here to tell everyone thier amp blew!!.