PaisleyWookie
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I'm still getting one of these at some point, I'm just not in a massive hurry because of all this COVID stuff, and I still have amps to play as well.
The 170 does have a very flat output if you tweak the tone controls to do so. They are very powerful and do not have detents at 0, so when I measured the freq response I had to twiddle the tone knobs a tiny bit around 0 to get it as flat as possible.Update: The SD PS-170 has a differential output, making it very difficult to measure since neither side of the speaker out can be tied to ground. By using the case as ground and listening to only the tip of the output I'm able to run sweeps, but I think something is still not right and I don't believe what I'm seeing. If I squint, it does appear that centered tone controls yield a flat output. Probably worth posing a question to SD and I'm planning to do just that.
Unfortunately, I'm not seeing any embedded photo or link.The 170 does have a very flat output if you tweak the tone controls to do so. They are very powerful and do not have detents at 0, so when I measured the freq response I had to twiddle the tone knobs a tiny bit around 0 to get it as flat as possible.
If anyone is planning on doing a lot of work with BTL digital power amps, a differential probe is a great investment. It makes life SO much easier. I just plug one of these into my audio interface (M-Audio 410) and it works great. It would take a bit of math to figure out absolute reading levels, but you don't really need that for frequency sweeps. Here's the link to the one I use:
Unfortunately, I'm not seeing any embedded photo or link.
So to get a near flat response from the 170, I should set the tone controls at or close to 0, not at 12 o'clock?The 170 does have a very flat output if you tweak the tone controls to do so. They are very powerful and do not have detents at 0, so when I measured the freq response I had to twiddle the tone knobs a tiny bit around 0 to get it as flat as possible.
If anyone is planning on doing a lot of work with BTL digital power amps, a differential probe is a great investment. It makes life SO much easier. I just plug one of these into my audio interface (M-Audio 410) and it works great. It would take a bit of math to figure out absolute reading levels, but you don't really need that for frequency sweeps. Here's the link to the one I use:
No - the EQ is boost and cut. 0dB is at 12 o'clock - ish.So to get a near flat response from the 170, I should set the tone controls at or close to 0, not at 12 o'clock?
The link to the probe was showing up earlier for me. Now it's just an Amazon icon, no link.
Thanks, sometimes it's good to check the details and not assume too much.No - the EQ is boost and cut. 0dB is at 12 o'clock - ish.
Still seeing nothing, but a 'Reply' operation shows the Amazon stock #. That's a rather expensive solution, however. I tried using a Jensen 1:1 line-level transformer but was getting very strange results with a lot of noise. I think the problem was my not using any sort of load. I'm betting the Class-D amplifier only behaves properly with a load on it. Will have to check that theory on the bench.
They are Class D power amps that don’t need to see a speaker load. You can power it just fine without one.These type of power amps normally need to be connected to a speaker don’t they, or they’ll break. Say I want to use this with my non headphone FM3, as a cab sim via headphones. Does it need to be connected to a speaker or will putting it through the headphones be enough?
Thanks.
Perfect thanks a lot.They are Class D power amps that don’t need to see a speaker load. You can power it just fine without one.
Minimum recommended load is 4Ohm.Anyone know if this would work with 2 ohms?
Thank you.Minimum recommended load is 4Ohm.
What are you referring to with regards to the updated tone controls of the 200? I have the 700 but I'm not too familiar with the 200.I'd kill for a stereo rack amp like the Powerstage 700 but with the updated tone controls of the 200.