talltxguy
Well-known member
I picked up a Tone Preserver from Vintage Sound Workbench. It's a variac with three settings: incoming line voltage, -6 volts, or -12 volts. On his website are pictures of the old Tone Preserver, which contains an analog monitor. The new ones contain a digital monitor. If you're rather have more control over voltage, you can pick up an Amp Maniac for a few bucks more, which allows you to dial in any voltage. The nice thing about Carl's variacs are that you cannot exceed the incoming line voltage, which is good for a clutz like me who is afraid of hitting accidentally bumping a switch that would zip the voltage to 140 or something crazy like that.
Usually the incoming voltage to my amp is 125 or 126 volts. When I took the pics this morning, the incoming voltage was a respectable 121 volts, which is a rarity! The variac doesn't make any noise and is rated at 4 amps.
I posted the results not because I received any kickbacks or anything good like that but because I preferred playing my Roadster in spongy mode - for any style of music. And the TA-15 does NOT have a spongy switch. In addition, my tech advised me a variac would be a good idea after installing the choke on my TA-15, which slightly increased voltage to the preamp tubes. So far as tone, I do think the TA-15 sounds and feels better at 112 volts as opposed to 124 volts just as I thought the Roadster sounded better in spongy mode than in bold mode.
Here are some bias results in the 25-watt mode:
Incoming voltage output tube mA
121 34.0
115 30.5
109 27.7
Usually the incoming voltage to my amp is 125 or 126 volts. When I took the pics this morning, the incoming voltage was a respectable 121 volts, which is a rarity! The variac doesn't make any noise and is rated at 4 amps.
I posted the results not because I received any kickbacks or anything good like that but because I preferred playing my Roadster in spongy mode - for any style of music. And the TA-15 does NOT have a spongy switch. In addition, my tech advised me a variac would be a good idea after installing the choke on my TA-15, which slightly increased voltage to the preamp tubes. So far as tone, I do think the TA-15 sounds and feels better at 112 volts as opposed to 124 volts just as I thought the Roadster sounded better in spongy mode than in bold mode.
Here are some bias results in the 25-watt mode:
Incoming voltage output tube mA
121 34.0
115 30.5
109 27.7
