Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TerryD on November 10, 2025, 06:41:52 am
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I bought an all tube amp off Ebay simple stereo in and speakers out with just 2 volume controls. Beautiful
Sounds great with my digital piano external speakers when I run the tube amp speaker outs through a cheap digital amp to eq and fine tune volume and smooths things out. The tube amp makes it sound great.
Tube amp alone distorts to easily. Digital amp before the tube amp not so great.
We are talking low low volumes. The point is a true piano sound.
Running the tube amp speaker out low volume into this cheap digital amp at low volume
Will this destroy anything? What are my options? Thanks, Terry
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You cah feed an amp with the output of one other amp but you must adapt the signal level of the output amp to the signal level of the input of the second amp that is way lower
In guitar world there is an amp that is devoted to send it's output to the input of other amps, the name is Herzog
but I doubt that the resulting effect is what you espect, the "Herzog" is planned to be a "Distortion Machine" and I think you'll not like its effect on playing a piano
if you search a description you find: The purpose of a Herzog amp is to provide a high-quality, all-tube, overdriven tone for guitars
here the Herzog schematic, you can see how a resistor acting as a signal lelel reducer is on the output section of the (Herzog) amp
(https://i.imgur.com/9kRdpCK.png)
And, yes, without a signal level match you can damage seriously your amp
Franco
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Each valve amp output needs a load, eg speaker, dummy load resistor, of the appropriate impedance or resistance. So for a stereo you need 2.
But why is it distorting so easily?
Maybe it's not working correctly?
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Wouldn't the input of this dinky little digital amp offer some resistence? If not how would I put the resisters in line with the inputs? I think it's just the nature of the piano outputs and dynamic range that tends to distort rather than anything wrong with the amp.
Could I just stick two 8 ohm resisters in line with the positive out wires left and right, say at 25 watts?
How about if I used a Niles Audio SVL-1 Speaker Volume Control Line-Level Attenuator and plugged the tube amp into that and then the digital amp to speakers
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Not 'in line', rather 'across'.
So 8R or whatever between speaker output hot and ground.
So that the resistor draws current like a speaker would.