The rule of thumb is the input impedance of the amp should at least be 10x the output impedance of the preamp. You can do the math and you will see if you think it is a good match?
PLEASE match Advice Pass Labs X350.5 (20k) to Hovland HP-100 (2500ohms) Miss-match ???
GUYS / GALS NEED YOUR HELP PLEASE!
A friend said this preamp is outstanding and will sound great with Pass Labs amps and to not get caught up in the specs but the measurements say different.
Pass Labs X350.5 amplifier with input Impedance 30k ohms Balanced or 20k ohms Single ended*
(*source Pass Labs Manual)
Hovland HP-100 source impedance 2500ohms*
(*source Stereophile)
Guys / Gals, can I used my Pass Labs X350.5 amp with Hovland HP-100 preamp? Has anyone used Pass amps with Hovland pre's. I will be using Magico S5 Speakers and Bricasti M1SE DAC but want it to sound the best it can. Should I just stick with the Aesthetix Calypso pre I was leaning toward before my gut said to go for the Hovland HP-100
Hovland HP-100 Preamplifier: * Output impedance: approximately 2500 ohms or according to Atkinson, Hovland HP-100 (2500ohms) its source impedance was high at 2.4k ohms, rising to 4.3k ohms at 20Hz. The partnering power amplifier would best have an input impedance of at least 47k ohms if the bass is not to sound lean*. The Pass Labs doesn't meet the x10 requirement it is supposed to but it is sort of close when looking at it. What do you guys think? I am not sure what to do but you guys will know what to do?
Stereophile: Its input impedance was a usefully high 100k ohms in the midrange and bass, with just a small reduction to a still-high 86k ohms at 20kHz. Despite the claim that the HP-100 uses a cathode follower output stage, its source impedance was high at 2.4k ohms, rising to 4.3k ohms at 20Hz. The partnering power amplifier would best have an input impedance of at least 47k ohms if the bass is not to sound lean.
Read more at https://www.stereophile.com/content/hovland-hp-100-preamplifier-measurements#YZXZfGLbbL2COkLR.99 https://www.stereophile.com/content/hovland-hp-100-preamplifier-measurements#YZXZfGLbbL2COkLR.99
A friend said this preamp is outstanding and will sound great with Pass Labs amps and to not get caught up in the specs but the measurements say different.
Pass Labs X350.5 amplifier with input Impedance 30k ohms Balanced or 20k ohms Single ended*
(*source Pass Labs Manual)
Hovland HP-100 source impedance 2500ohms*
(*source Stereophile)
Guys / Gals, can I used my Pass Labs X350.5 amp with Hovland HP-100 preamp? Has anyone used Pass amps with Hovland pre's. I will be using Magico S5 Speakers and Bricasti M1SE DAC but want it to sound the best it can. Should I just stick with the Aesthetix Calypso pre I was leaning toward before my gut said to go for the Hovland HP-100
Hovland HP-100 Preamplifier: * Output impedance: approximately 2500 ohms or according to Atkinson, Hovland HP-100 (2500ohms) its source impedance was high at 2.4k ohms, rising to 4.3k ohms at 20Hz. The partnering power amplifier would best have an input impedance of at least 47k ohms if the bass is not to sound lean*. The Pass Labs doesn't meet the x10 requirement it is supposed to but it is sort of close when looking at it. What do you guys think? I am not sure what to do but you guys will know what to do?
Stereophile: Its input impedance was a usefully high 100k ohms in the midrange and bass, with just a small reduction to a still-high 86k ohms at 20kHz. Despite the claim that the HP-100 uses a cathode follower output stage, its source impedance was high at 2.4k ohms, rising to 4.3k ohms at 20Hz. The partnering power amplifier would best have an input impedance of at least 47k ohms if the bass is not to sound lean.
Read more at https://www.stereophile.com/content/hovland-hp-100-preamplifier-measurements#YZXZfGLbbL2COkLR.99 https://www.stereophile.com/content/hovland-hp-100-preamplifier-measurements#YZXZfGLbbL2COkLR.99
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- 111 posts total
I have a bit more info from Stereophile: They say someone with solid state amps with input impedance of under 10k ohms this will not be a good match (see below) but my Pass Labs X350.5 has a 20k ohm impedance. So it is double what they say I should avoid so this makes me think I am ok but just not sure. I am hoping someone much smarter than I with much more experience and knowledge can chime in and help me. I thought this info helpful and wanted to share. I know I can be safe and stay away but its a local sale and a decent deal so I wanted to turn to you guys/gals! Thanks Stereophile: This graph was taken into the kind 100k ohms load. Reducing the load to 10k ohms, a typical input impedance for many solid-state power amplifiers (fig.5), increased the second harmonic almost tenfold, to -60dB (0.1%), and added some third harmonic. Dropping the load to the admittedly punishing 600 ohms raised the second harmonic to -44dB (0.6%, not shown). It is probably inadvisable to use the Hovland with those few power amplifiers that have input impedances below 10k ohms. Read more at https://www.stereophile.com/content/hovland-hp-100-preamplifier-measurements-part-2#fmWMvbWLqXD0mMfO... |
Yes, definitely a bad match. You have the answer in your post. "The partnering power amplifier would best have an input impedance of at least 47k ohms if the bass is not to sound lean*." I had experience with a bad matching pre/power. In addition to lean bass, it also sound lifeless, no dynamics. When I changed amps to a proper match and 1/3 less power, the bass was there and it was more dynamic with less power. Also, the first amp sound great with a correct matching preamp. |
- 111 posts total