| Author | Message | ||
     Jimmy -aus- |
Hi, I'm new so be kind. I have a 210 HD130 (numeral not letters on the badge), and apart from the power valves, there is another preamp looking valve with the removable metal cover. My amp tech said that the reverb unit is driven by this, as the pre amp is SS. I've read thru this site, and everyone talks about a phase inverter valve, but no one has mentioned a reverb driving valve. So.. 1. Is my amp tech (who is really good and experienced) confused, & 2. What does a phase inverting valve do anyways? Oh, and while were on the topic, can anyone suggest why MM coupled 2 10inch speakers with 130 watts?!? It seems insane, I always have to use external speaker boxes for gigs (and then it is PLENTY loud). Thanks! | ||
| John Drexler |
It's a 12AX7 Phase Inverter tube. | ||
| michael kaus |
John is right. THe 12ax7 is a phase inverter tube. Your <tech> is confused. That is a common misconception that it is a reverb driver but if you look at the schematic, you will see it's nowhere near the reverb circuit. It's part of the driver circuit so maybe you should find someone familiar with MM's to service it! Mike. | ||
| Jimmy -aus- |
Thanks for the responses! Well thats frightening!Looks like most of his experience is in fender and marshall! When the guy first saw my amp he said the speakers were wired up wrong and put them back the "correct" way. I've just read here that HD210 130's speakers are wired the opposite of alot of amps! If it is wired up wrong will this lower the transformers life or something? Thanks | ||
| michael kaus |
I don't know what he meant by wrong or what he did to them but there should be two eight ohm drivers wired in parallel with the hot side going to the north end of the speakers-pretty basic. It gives you a total of four ohms of load. If they were wired in series or with the + side going to the negative side of the speakers, it really wouldn't hurt the transformers, it may just sound funny as it would be retracting the voice coil instead of pushing it out. The important thing is to make sure they are both going the same direction at the same time. that's why you want the + side to the north end of the speaker coil.Mike. | ||
| Jimmy -aus- |
Well it sounds ok so I guess it must be fine. If anyone knows of a MM amp guy in sydney please email me! thanks guys! |