Ampeg SVT Blackline 600 ohm line input?

[Kirkelstein]

Hi-I have an Ampeg SVT blackline with an input jack on the front labeled "Line Input 600 Ohms". I thought that was stock until a guy on Facebook Marketplace pointed it out. The graphic is really good! Does anyone know what this might have been used for? Thanks for the help!

 

[Stylee Mousse]

To run in an MP3 player so you can practice to trax! Oh wait, a record player….

seriously tho, I can see applications but none of them sensible in this era.

 

[Kirkelstein]

To run in an MP3 player so you can practice to trax! Oh wait, a record player….

seriously tho, I can see applications but none of them sensible in this era.

Thanks! A guy thought maybe something to accommodate active pickups or some processor. I'm definitely intrigued!

 

[Stylee Mousse]

So a low impedance line input definitely wouldn’t work for any bass. That would be useable (probably) for an input from a mixer.

since it’s a mod we would have no idea how it’s wired so…

 

[Kirkelstein]

So a low impedance line input definitely wouldn’t work for any bass. That would be useable (probably) for an input from a mixer.

since it’s a mod we would have no idea how it’s wired so…

Thanks-Appreciate it!

 

[agedhorse]

That may not be a user mod, but could be a factory added option for either a specific player or a pre-production prototype, to plug an active line level source (like an SVP preamp or drum machine) into.

This input is normally located on the back, and is labeled ext amp in. A look at how the wiring was executed would shed light on how it came to be.

 

[Kirkelstein]

That may not be a user mod, but could be a factory added option for either a specific player or a pre-production prototype, to plug an active line level source (like an SVP preamp or drum machine) into.

This input is normally located on the back, and is labeled ext amp in. A look at how the wiring was executed would shed light on how it came to be.

Thanks for that-I'll get a looksee in there and get some pics. Appreciate the insight.

 

[mborn]

Back in the dark ages of radio there were 600 ohm transmission lines. That standard was moved over to audio (also during the dark ages) when using long twisted pair audio lines. It also was related to the DB standard which was referenced to 600 ohm standards. Now you know hold old I am.

You can google 600 ohm audio and get a deeper explanation.

 

[agedhorse]

~600 ohm input impedance is what the SVT's power amp was designed around.

 

[Kirkelstein]

~600 ohm input impedance is what the SVT's power amp was designed around.

Thanks for that-I'm getting a picture of the wiring. It's very interesting.

 

[txhawaii]

Back in the dark ages of radio there were 600 ohm transmission lines. That standard was moved over to audio (also during the dark ages) when using long twisted pair audio lines. It also was related to the DB standard which was referenced to 600 ohm standards. Now you know hold old I am.

You can google 600 ohm audio and get a deeper explanation.

google has an article about big radio studios seemingly having issues with "how large networks with long wire runs could be connected while at the same time being able to keep audio levels and frequency response correct."

this modified svt might have come from a recording studio from the dark ages? probably nothing too special for the time considering the technology needs/issues from 50 years ago.

maybe someone from the portaflex group will chime in with info.

THE 600 OHM AUDIO STANDARD, WHERE DID IT GO? - FM Systems

 

[JIO]

Is the fan original or is it a mod?