OT Crossover Wiring

**westend9** · March 8th, 2017, 02:42 AM

There are about as many ways to wire an amp as grains of sand on a beach, some better than others.

One criteria of the above example was the size of the case as dictated by the customer. It was pretty much a 10 lb sausage placed in a 5 Lb casing.

I've found no instances of any audiofoolery in having AC wires in close proximity. Typically, phases are opposite so that there is inherent cancellation of induction. The transformer was encased in it's copper and brass housing to eliminate inductive noise to the amp boards. The length of input and output leads to those boards, dictated by the placement of the high temperature devices on the heatsinks. This is a Class A amp so it operates at it's highest quiescent current when at idle. Believe me, temperature rules when biasing this amp.

I thought it might be of some interest to see the variety of different wire used inside the amp. Maybe not.

I don't see the obsession about not using a terminal block. They are made for exactly this purpose and others went before using similar process. I find it neater and more secure than soldering and laying wire in air space or laying them down within the case. Again, grains of sand.

About the only caveat I had in retrospect about "neatness" is that the input wiring could have become an antenna because of the layout. In use, that was proven to not be the case.

BTW, the input wiring from the switch to the boards (white) is teflon jacketed, teflon and copper shield, A Belden Product manufactured to use in very high frequency mil spec communication wiring. I've used it in a number of audio applications, including high-end SS preamps and it has shined in those applications.

**LowOhms** · March 8th, 2017, 03:22 AM

Originally Posted by westend9

There are about as many ways to wire an amp as grains of sand on a beach, some better than others.

One criteria of the above example was the size of the case as dictated by the customer. It was pretty much a 10 lb sausage placed in a 5 Lb casing.

I've found no instances of any audiofoolery in having AC wires in close proximity. Typically, phases are opposite so that there is inherent cancellation of induction. The transformer was encased in it's copper and brass housing to eliminate inductive noise to the amp boards. The length of input and output leads to those boards, dictated by the placement of the high temperature devices on the heatsinks. This is a Class A amp so it operates at it's highest quiescent current when at idle. Believe me, temperature rules when biasing this amp.

I thought it might be of some interest to see the variety of different wire used inside the amp. Maybe not.

I don't see the obsession about not using a terminal block. They are made for exactly this purpose and others went before using similar process. I find it neater and more secure than soldering and laying wire in air space or laying them down within the case. Again, grains of sand.

About the only caveat I had in retrospect about "neatness" is that the input wiring could have become an antenna because of the layout. In use, that was proven to not be the case.

BTW, the input wiring from the switch to the boards (white) is teflon jacketed, teflon and copper shield, A Belden Product manufactured to use in very high frequency mil spec communication wiring. I've used it in a number of audio applications, including high-end SS preamps and it has shined in those applications.

He should have mounted the transistors two inches higher on the heart sink, raising the PC boards by that distance. He could add a $5.00 bracket, at the top of the amp, with a plexiglass plate bolted to it. The RCA input signal jack could be mounted on that plexiglass ( double insulation ) plate. The amplifier's top cover could be plasma cut during construction, to allow the end user access to the RCA jacks. Lead length would be direct, and maybe two inches, or less.

Its almost a FREE better-engineering solution, using an open mind, common sense, and its from me, a business major. The boards will also be further-distanced from the power transformer.

He needs to place the AC outlet, some wheres on the opposite side of the amp. And use a 20 A. IEC, not a crummy typical 15 A. one.

Low Ohms, .......Jeff Medwin

**westend9** · March 8th, 2017, 03:36 AM

Originally Posted by LowOhms

He should have mounted the transistors two inches higher on the heart sink, raising the PC boards by that distance. He could add a $5.00 bracket, at the top of the amp, with a plexiglass plate bolted to it. The RCA input signal jack could be mounted on that plexiglass ( double insulation ) plate. The amplifier's top cover could be plasma cut during construction, to allow the end user access to the RCA jacks. Lead length would be direct, and maybe two inches, or less.

Its almost a FREE better-engineering solution, using an open mind, common sense, and its from me, a business major. The boards will also be further-distanced from the power transformer.

He needs to place the AC outlet, some wheres on the opposite side of the amp. And use a 20 A. IEC, not a crummy typical 15 A. one.

Low Ohms, .......Jeff Medwin

You truly are not looking at the layout of this amplifier and understanding some of the design criteria. You repeat that 2" thing like aliens brought it to the Egyptians. There is no possible placement of the amplifier boards that would accommodate the use of a 2" length of wire. The boards are approx 6" in length and there are positions of connections that prohibit the use of a such a small length. Further, a short length isn't necessary to carry the signal to/from the amp board. What's more important is that the junction temperature of the main devices be dissipated as efficiently as possible, i.e. no, they can't be raised to accommodate a 3" shorter wire. This is just foolishness, I'm now understanding. It is like teaching pigs to sing--it's difficult and the end result doesn't sound that good.

BTW, this will be my last post where Jeff Medwin has any type of discussion about or within.