Techron! (Crown PS-200)

[timgr]

Techron 7520s:

These are industrial amps. They are dead ringers for the PS-200, except for the brown face plate and labeling, and the BNC inputs rather than phono jacks on the back panel.

Functionally, the only difference I see is that the Techrons will function down to DC, and the PS-200 has a low-frequency protection circuit. According to the PS-200 specs, the low frequency protection is defeatable with an unspecified modification.

So, any of you old hands out there know about the low frequency issue? Is there a jumper somewhere that I can change? Is there any hazard to using these Techrons as audio amps, sans the low frequency protection?

They sound great, BTW.

 

[KentTeffeteller]

How about going to AE Techron's site, emailing someone there, and find out. They are superbly helpful. They handle repairs on some older Crown components too.

 

[Renzor213]

Curious what you'll find when searching Techron on the web, as it's a very popular car fuel system cleaner, marketed by Chevron. Actually very good stuff.

 

[timgr]

Curious what you'll find when searching Techron on the web, as it's a very popular car fuel system cleaner, marketed by Chevron. Actually very good stuff.

Heh. I typed in "Techron 7520" and went right to the user manual.

Google takes all the fun out of searching

So what's the connection between Crown and Techron today? From Kent's post, it sounds like they parted at some point. Back in the day, I was told that Crown is Techron.

 

[totem]

Let,s not leave out Amcron, the name used in certain parts of the world.

 

[KentTeffeteller]

AE Techron took over Crown International's industrial amplifier line. They built the non audio amps afterwards. Amcron was used in some countries where the Crown trade name wasn't able to be used. Amcron was an acronym for American Crown. Missionary Tough in the great Clarence Moore tradition. AE Techron was a spin off of Crown. Techron was originally Crown's industrial products.

 

[mhardy6647]

Techron 7520s:

These are industrial amps. They are dead ringers for the PS-200, except for the brown face plate and labeling, and the BNC inputs rather than phono jacks on the back panel.

Functionally, the only difference I see is that the Techrons will function down to DC, and the PS-200 has a low-frequency protection circuit. According to the PS-200 specs, the low frequency protection is defeatable with an unspecified modification.

So, any of you old hands out there know about the low frequency issue? Is there a jumper somewhere that I can change? Is there any hazard to using these Techrons as audio amps, sans the low frequency protection?

They sound great, BTW.

Tim... duude! Nice to see you here; didn't know you were still in the area!

 

[d3imlay]

If my memory serves me from 20 years ago, there was a higher power version called an MA 10,000. It only put out about 50 volts but it could drive well under 1 ohm. They claimed that one amplifier ran the entire PA at Indy.

There was an industrial version used in Picker MRI systems. I believe they used 4 of these 150 lb amp in each system. The amplifier was an H bridge design and used a bank of 20 outputs per leg.

I worked part time for a company called Sound Values and latter Sound Valves who bought a truck load of these amps. I worked on a bunch of them. A number of the reconditioned ones were sold to night clubs. They couldn't be used in home applications as they required 3 phase power. Actually I did modify one for use on single phase 240 volts just to test it. I never carted one home though, not at 150 LB.

 

[mech986]

If my memory serves me from 20 years ago, there was a higher power version called an MA 10,000. It only put out about 50 volts but it could drive well under 1 ohm. They claimed that one amplifier ran the entire PA at Indy.

There was an industrial version used in Picker MRI systems. I believe they used 4 of these 150 lb amp in each system. The amplifier was an H bridge design and used a bank of 20 outputs per leg.

I worked part time for a company called Sound Values and latter Sound Valves who bought a truck load of these amps. I worked on a bunch of them. A number of the reconditioned ones were sold to night clubs. They couldn't be used in home applications as they required 3 phase power. Actually I did modify one for use on single phase 240 volts just to test it. I never carted one home though, not at 150 LB.

the Peterson's and Stereo Cost Cutters as I recall? Sold them some Dynaco stuff, bought some Dynaco stuff from them in the early 80's. What are they up to now?

 

[KentTeffeteller]

Here's you a link to the site. www.aetechron.com

 

[timgr]

...
There was an industrial version used in Picker MRI systems. I believe they used 4 of these 150 lb amp in each system. The amplifier was an H bridge design and used a bank of 20 outputs per leg.
...

GE used Techrons for MRI systems too, at least into the 90s. I expect you are referring to gradient amplifiers, which apply gradient fields to impart spatial encoding to the MR signal. MRI amps are constant current devices, which are typically used stacked and can swing up to thousands of volts when slewing. A typical configuration would be 3 channels (X, Y, Z) stacked, so 6 units. The field produced by the coils is a function of current, and there is significant coil impedance to overcome.

The advance of MRI has left these simpler amps behind, and they only use purpose-built switchers today, AFAIK. I was given this pair of the 7520s about 15 years ago; they came from MRI equipment too, and were shim field amps. The shims are used to smooth out the main field. The magnetic susceptibility of the subject goofs up the main field homogeneity a lot, and the shims attempt to compensate for the disturbance. They had a constant current accessory from Techron plugged in to the socket on the back when I got them.