SuperBee
1518 posts
Nov 08, 2013
5:18 AM
|
I have a 60s era pa, 50 watt, 6CA7 valves I think. I'm trying to understand how to connect a speaker to it but professor Google is not much help tonight.
The thing has a tab strip with various connection possibilities to connect lots of speakers, of minimal impedance, on 100 volt line. but I think I don't want to go there. I guess I really need to open it up and see how it's set up. im thinking I'll need to replace the OT to be able to use it like a guitar amp. Does that seem likely?
----------
JellyShakersFacebookPage
JellyShakersTipJar
|
HawkeyeKane
2143 posts
Nov 08, 2013
7:26 AM
|
" im thinking I'll need to replace the OT to be able to use it like a guitar amp. Does that seem likely?"
Without pictures, it's hard to say. Lots of old PA heads have the ability to run different speaker loads by moving a spade connector between different lugs.
6CA7's you say? Well....the old Kalamazoo Bass 50 used a push-pull pair of those as well for a 50W output. They loaded those up with a pair of Jensen C10N's. You might look into something similar. Offhand...I'd say Lil' Buddies or 10F150-O's.
----------
Hawkeye Kane
Last Edited by HawkeyeKane on Nov 08, 2013 7:31 AM
|
Greg Heumann
2455 posts
Nov 08, 2013
7:57 AM
|
I'm guessing you're looking at a choice of output impedances, PLUS the 100V line option. Mascos had this too, though theirs was a 70V line. All of the choices are coming from different taps on the amp's output transformer. The impedance choices on the Masco are something like 2,4, 8, 16 and 32 ohms. I.e., you shouldn't need to replace it - only use the correct tap, which is a function of the impedance of the speakers you want to connect to and how you connect them together (parallel or series).
I don't know much about the 100V option except it was a way to run a lot of speakers (possibly that had their own little amplifiers?) and you probably don't want to use that.
----------
***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
BlueState - my band
Bluestate on iTunes
Last Edited by Greg Heumann on Nov 08, 2013 7:59 AM
|
SuperBee
1519 posts
Nov 09, 2013
5:39 AM
|
Great, I think I understand now. I was thrown by the table on the back which lists how many 600 ohm speakers add up to various impedance loads, and how to link the terminals accordingly. I think the lowest-impedance output I can set up is 12 ohm. Next is 18. I expect I can work with those.
----------
JellyShakersFacebookPage
JellyShakersTipJar
|
