|
|
| Re: Vibe Controls SC-150 [message #8280 is a reply to message #8279] |
Sun, 18 February 2007 16:40   |
rodak
Messages: 516
Registered: October 2001
Location: Georgia
|
Senior Member |
|
|
The Vibrato should be a pitch change, and the Tremelo a volume change. There is no optical circuit in the SC-150 (unlike, say, a Twin reverb). It does sound like your footswitch is messed up, though.
I also have an SC-150, and while the Tremelo works well, the Vibrato doesn't do much in the way of pitch change - it's more like a Tremelo with an irregular waveform. I've not yet bothered to try to figure it out, but when I do, I'll probably come here for help, too (so I'm hoping one of the other tech guys here will offer some direction!)
www.combo-organ.com
|
|
|
|
| Re: Vibe Controls SC-150 [message #8281 is a reply to message #8279] |
Sun, 18 February 2007 17:12 |
oldnavycdr
Messages: 38
Registered: July 2006
Location: Sanford, NC
|
Member |
|
|
You described my issue exactly. Perhaps the SC-150 just doesn't have a very strong vibe? So, I'm correct in thinking that moving the trem-vib pot should control the change from trem to vib? Thanks for the reply. I'll check out the foot switch and see what is up with that and wait for other posts on the vibe vs. trem.
Old Navy
|
|
|
|
|
|
|
|
| Re: Vibe Controls SC-150 [message #8286 is a reply to message #8285] |
Mon, 19 February 2007 12:48 |
chicagobill
Messages: 2006
Registered: April 2003
|
Senior Member |
|
|
Rodak is correct, the vib-trem control is supposed to change the effect from pitch change to volume change. The metal front amps do this very well, but in my opinion the plex front circuit is not as effective.
The circuit is basically the same as the 200B vibrato, but the 200B is designed as Vibrato only. The vibrato works by mixing the straight in-phase signal with a frequency modified out-of-phase signal. The balance of the signals mixed together is what determines the depth of the vibrato effect.
If the tremelo is working strong and can be varied with the speed and depth controls, then I would check the balanced modulator circuit centered around transistor Q10003. The transistor, the Trem-Vib pot, and the 0.0047 capacitor (C1011), should all be checked.
Bill
|
|
|
|
| Re: Vibe Controls SC-150 [message #8288 is a reply to message #8286] |
Mon, 19 February 2007 20:37 |
oldnavycdr
Messages: 38
Registered: July 2006
Location: Sanford, NC
|
Member |
|
|
It just keeps getting weirder. While checking the amp out today I discovered that the reverb was being controlled by the Intensity pot which should control the trem-vib. Turn Intensity off, reverb goes off. Turn Intensity on, reverb comes back on. This was with the footswitch plugged in. I disconnected the footswitch and got the same result. I then used a guitar plug to "short" the footswith and things returned to normal. I think it is time to get this baby in for a check up. Anyone know a quality Kustom tech in the Northern VA/Washington DC area? The rest of the amp is just fine with Killer Kustom sound...but there seem to be some issues here with the effects and I don't think this baby has had a thing done to it since it came out of Chanute in '72.
Old Navy
|
|
|
|
VintageKustom.com
Search
Help
Members
Register
Login
Home
]