Wondering Ampegs

[catalin gramada]

Hello. Take a look please at first stage of Ampeg V4B schematics. It is a 100k resistor loading the stage before tone shape network. As I know E Hull was almost fanatic to get rid of distorsions in Ampeg circuits. Why do You think it was loaded so heavy? With 100k in those position can get a loss by a factor of 2 I suppose. To be this one

of the reason? ...I don.t think so...What are You thinking about,please. Thanks

https://irationaudio.files.wordpress...-schematic.jpg

[Justin Thomas]

I can't answer your question, but I can say that E. Hull was out of the company at least a few years before the V4B came along, so his prohibitions against any distortion were no longer applicable. When he left the new owners knew full well that they would have to make changes to stay competitive in the burgeoning rawk market. Ken Fischer actually designed a few distortion circuits for them when he joined in the mid-60s, but they were poo-pooed by Hull at the time. I think they done good.

Justin

[Leo_Gnardo]

The V4B's I've run across get plenty loud and clean, with the power amp running out of steam before the preamp starts clipping. I sure wouldn't worry much about that 100K load resistor. If it worries you, change it out for a 1M or anything else you like, should make for a bit brighter tone but that's about all.

[g1]

I think it would be too easy to distort that first stage with hot pickups if it did not have that 100K load there.
Compare it to the guitar version V4. The guitar version has an attenuator ('sensitivity') switch before the first stage. If you do not use the attenuator, you can not get a clean sound unless you turn the guitar volume way down when using hotter pickups. (the distortion is already occurring before the amp volume control)
I loaned out my V4 to a friend once, he complained he could not get it to clean up. It was because he left the 'sensitivity' switch on 0db when he needed to set it to -9db.

[Justin Thomas]

Makes sense to have it as a permanent fixture, then - my Mustang Bass puts out a more substantial signal than my Tele... Why bother even leaving it as is and adding a switch on a Bass Amp? Just attenuate & be done - no complaints!

Because how many guitar & bass players RTFM anyway?

Justin