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Dynaco ST-150 and Topping D50s signal levels

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Jan 19, 2021
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#1
This is my first post and I’m unsure if this is the right forum for it, so please correct me if it should be elsewhere.
I recently acquired a very nice Dynaco ST-150 which I’m going to refurb, but which works well at present. I wanted to try it with a Topping D50s dac which I purchased because of comments on this site. The chain looks like qobuz->roon->topping d50s(usb)->dynaco st-150->elac dbr speakers.
This is in a small den. The dac ouput is 2v at 0db and the st-150 is rated 75w rms into 8 ohms at 1v in.
To achieve 75db at my listening position, with roon dsp volume at 0db, I have to lower the output on the dac to -10 to -15db depending on source material.
So my question. Setting the dac at -6db and roon at 0db I should be getting about 1v out of the dac, correct?
Is it best to vary the rest of the volume with roon’s 64 bit dsp volume control or is it better to leave roon at 0db and vary all volume with the topping d50s volume control?
My apologies in advance if this is a stupid question.
 
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Jan 19, 2021
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Thread Starter #2
Anyone have a suggestion on this? I have tried it both ways and to tell the truth I don’t hear the difference. I also replaced the speaker fuses with .5A quick blo. At -6db( which should be 1v output from the topping) on roon dsp volume( about 75db at my listening position 7 feet away) I measure on most passages between 2-3v at the speaker output. Occasional heavy bass passages will reach 5 volts. Looking at Amir’s review let’s say 6-7 ohms at the speakers on bass passages, does this mean I’m really only pulling less than 1A? Forgive me if I’m totally misunderstanding this.
 
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