| Author | Message | ||
     Erik |
Not in front of my HD212 at the moment, but there is a jack on the back that is marked "external speaker" or something. What ohm rating is this? Would this allow me to use another 212 speaker cabinet? Would I then switch the OHM rating from 8 to 4? Thanks in advance for any help. | ||
| michael kaus |
Your jack should be a series jack. It SHOULD say that on the back, by the jack somewhere. If it does, normally you will use the 4 ohm side for internal speaker only and 8 ohm for when you add a speaker. Mike. | ||
| Erik |
There is no note of it being a "series" jack. I'm assuming that the plug would go to an 8 Ohm cabinet and then I'd switch to 8 Ohm but then I'm also getting confused about the wiring on the built in speakers: Does the wiring have to be in parallel on the built in 212 speakers? Another stupid question -- how would I tell? Why would they even have the jack there if the wiring to the speakers wouldn't be set correctly? Thanks in advance! | ||
| Joseph Beggy (navan55) Username: navan55 Registered: 10-2007 |
Hi recently bought a 212HD which sounds great. It has a missing Polarity switch. This has been replaced with what appears to be an input jack!!! The hi-Low switch is also missing and now operates as an on-off only!! It originally came from Holland. Hence a two pin plug needing a three pin adapter. Lastly I'v been offered a MM212 75Watt any comments. Haven't gone through with the sale as yet. What difference can I expect. Thanks. Joe. from Ireland. PS. Looking for the above switches and MM knobs. Tricky. pps Michael has been a great help so far. | ||
| Steve Kennedy (admin) Username: admin Registered: 03-2002 |
Since the amp has been modified from standard, there is no way to know exactly what you have unless the amp is opened up and a qualified Tech or Engineer compares the original schematic (available on this site) to the circuitry inside your amp to determine what it is now and what would be necessary to restore it to the factory configuration. As far as the Polarity switch goes, you are better off without it. This switch simply connects a capacitor to ground on either one of the primary line connections (to bleed-off AC line noise). If this cap shorts, it will connect one side of the AC line to the chassis of the amp. This is why this capacitor is known as the "Death Cap"! This creates a potentially deadly scenario where your guitar strings are at AC line level (because you guitar is plugged into your amp and is grounded to the now "hot" chassis) and your microphone is at ground potential. If you are playing and touch the mic with your lips you get shocked with full AC line current flowing through your body. Not a pleasant experience and it could easily kill you! People have died in this fashion (although it is relatively rare). My advice would be to download the schematic, find a local tech to check things out and go from there. Steve | ||
| Lars Verholt (lmv) Username: lmv Registered: 11-2009 |
The 'polarity' switch was never on there if the amp was originally sold in Europe. The space where this switch would be in a US issue amp was filled with a master power switch (dual pole). A relatively common modification was the hardwiring of either 'lo' or 'hi' by making the front switch a simple on-off button. I've also seen an input jack going to the master volume control (so you can use an outboard preamp). All these mods are easily reversed. As Steve points out, a qualified technician would be able to fix it with the schematic at hand. The dual pole master power switch definitely makes sense in a 230VAC mains power environment. Sincerely, Lars Verholt | ||
| Joseph Beggy (navan55) Username: navan55 Registered: 04-2014 |
Tanks Steve and Lars. I will keep you up to date when I have it sorted. Firstly I'll get the schematics and work from there. Joe. |