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
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Thanks guys - this is great stuff... I knew I would get great feedback from you guys. Excellent - thank you !!!

 Al, you are right, both of these are poor matches for sure. I like being able to look at the specs and get feedback from people that understand this better than I.

I know enough about it to ask for help and feedback. Both these pres seem to be poor specs matches even though I know they may sound great.

The only reason I don't want go to a Pass preamp is because I really want to try and get tubes into the chain.

I am getting new to me speakers delivered on Monday. Magico S5's and many of the folks tell me their sealed box design can really benefit from warming a little warming up of the lower midbass being one not used to the speed and type of bass these offer. Little tube richness in there plus I love tubes but know to properly drive Magico's would cost a fortune with tubes. Heck the Pass X350.5 is pretty close to a tube amp so a tube pre with this amp should make a tube lover happy - I hope :)

My buddy told wanting tubes try and find a tube amp that can both get the desired output impedance and preferably one without a cathode follower. Those tend to cause different impedance swings verse a pre uses tubes in paralell to lower impedance.

In my price range what do you think of a BAT VK50SE. It is in my mid $2k price range and people speak high of them. Some say they can be a bit dark but people that combo with Magico speaker might be a nice match. There is a 51SE but its a $1,400 more and out of what I want to spend.

What do you guys think? Thanks so much! 





Pass Labs X350.5 amplifier with input Impedance 30k ohms Balanced or 20k ohms Single ended*

I believe that you have those two numbers reversed. The way I read it on the Pass Labs website:
Input Impedance (SE & BAL Kohms)   30/20.

The way that reads to me is that the Input impedance is 30Kohms for SE, and 20Kohms for BAL.

Still, the fact that the Hovland output impedance rises to 4.3 Kohms at 20 Hz would make it a poor choice for even an amp with a 30K input impedance. I would think a 50Kohm amp would be the minimum for the Hovland.
The final for the HP-100 is not a cathode follower. It is Jfet, so it is a source follower. It is coupled through a hermetically sealed tantalum capacitor.
Thanks guys 

Darn I was all set with the BAT until I read this: 

The BAT's input impedance measured a high 220k ohms, and its output impedance at 1kHz was 414 ohms from both sets of output jacks. This figure rose slightly to 422 ohms at 20kHz, which is a negligible change. At 20Hz, however, the source impedance was a very high 4.6k ohms, which suggests undersized output coupling capacitors, even with the Six-Pak option, which I assume was fitted to the review sample. Care should be taken when mating the VK-500SE with power amplifiers that have an input impedance of less than 10k ohms. The voltage-divider action of its high source impedance at low frequencies and the power amp's input impedance will roll off the low bass.
Read more at https://www.stereophile.com/content/balanced-audio-technology-vk-50se-line-preamplifier-measurements...

One of the guys above smartly stated he thinks the Pass is 30k input impedance - so that is better but still everyone says must be careful with tube preamps and the input impedance specs are great unil 20k.  i just don't want the BAT's bass to roll off. I mean 20k is low so I don't want to go crazy over the numbers but i also want to be smart and set it up properly. Do you think the BAT could be ok?