ShortScale.org

From GAK
"The Epiphone Valve Junior Head Amp is perfect for any situation where the sound pressure level has to be low, but the tone perfect, with a 12XA7 preamp valve and a EL84 output valve operating in single-ended Class A circuitry. Single-ended means the amp's output is not referenced to ground, so you get the amps' full voltage swing into the speaker. Class A means the output valve is always turned on for a valve amp's trademark quick response with loads of harmonics when overdriven.

Mojo salespeople at work....

"Keep the Valve Junior volume at about 3 and you’ll get punchy, clear tone that makes the strings of your guitar feel like they know what you’re going to play before you even hit them."

That is a damned lie. Strings aren't sentient.

NickS wrote:the amp's output is not referenced to ground, so you get the amps' full voltage swing into the speaker

If the amp doesn't go to ground, then there can't be a voltage. Voltage is the difference in charge between lead and ground.

Clearly I need a ground lift on my amp. It may hum like buggery and potentially electrocute me when it goes faulty (Stone The Crows!), but I'll have freed it to generate the full voltage swing!

TBH, a floating output is fine. It doesn't need to be referenced to ground unless your design requires it e.g. for negative feedback. Bridging amps don't, for example; it's just the voltage of one terminal relative to the other, and old systems with no mains transformer for HT didn't (some old record players and radios - EAR, for example, just used a diode to rectify the mains input as HT for the valves and had a small 6.3v transformer for the heaters). The VJ has a floating output (which is good if you want to take a line directly from the speaker) but that doesn't affect the voltage swing one whit.

NickS wrote:Clearly I need a ground lift on my amp. It may hum like buggery and potentially electrocute me when it goes faulty (Stone The Crows!), but I'll have freed it to generate the full voltage swing!

TBH, a floating output is fine. It doesn't need to be referenced to ground unless your design requires it e.g. for negative feedback. Bridging amps don't, for example; it's just the voltage of one terminal relative to the other, and old systems with no mains transformer for HT didn't (some old record players and radios - EAR, for example, just used a diode to rectify the mains input as HT for the valves and had a small 6.3v transformer for the heaters). The VJ has a floating output (which is good if you want to take a line directly from the speaker) but that doesn't affect the voltage swing one whit.

this is exactly what i was about to post