Pioneer HPM-100 Crossover Project

westmassguy

This was an interesting project. The HPM-100s are well regarded, and have quite a following. Unlike many Japanese models from that era, these were well designed, and don't have ridiculously large woofers in a small cabinet.
The upgrade consisted of replacing the two existing Film Caps, one NP Electrolytic, one Resistor, one Inductor, and the Binding Posts. The modifications were done per an AK thread. The crossover point between the woofer and midrange was lowered.
Sonicaps, Mills Resistors, Jantzen Inductors, and small, imported, solid copper Binding Posts were chosen.
Due to the size of the Sonicaps, new, longer standoffs were required. Some caps were relocated to the bottom of the board. The old binding posts screwed directly to the circuit board. The new Binding Posts were not long enough, so #16 gauge wire was used to connect the new Binding Posts to the circuit board. Due to the size of the new Inductor, the extension wires were looped, so the board could be removed, slid through the existing opening and then re-secured if needed.

westmassguy

TNHNDYMAN

sweet project. How does it sound now compared to original?

westmassguy

I'll know once the owners installs them.

pitdogg2

Very cool I had the same yrs ago like them except for the woofer flex. When driven by a good amp they would suck in a dimple on the dust cone and I swear I could hear it....or maybe it was the mushrooms:)

westmassguy

Thanks pit, it was the mushrooms...........

pumpkinman

I always love seeing projects like this


Thank you for sharing

westmassguy

You're welcome Sir

voltz

pumpkinman wrote: »

I always love seeing projects like this


Thank you for sharing

Agree! I love seeing a project like this come together! gotta love them Sonicaps.

westmassguy

voltz wrote: »

pumpkinman wrote: »

I always love seeing projects like this


Thank you for sharing

Agree! I love seeing a project like this come together! gotta love them Sonicaps.

Darryl, I'm giving you no-name Chinese Electrolytics in your CRS+s

voltz

are you going to at least write Sonicap on them for me

that reminds me of that post someone had put up of a picture of a really big cap with a small cap inside LOL.

westmassguy

I'll use a P-Touch
I'll spray them white too

Conradicles

Great work those are some sweet speakers.

westmassguy

Thank you Sir

Nightfall

voltz wrote: »

are you going to at least write Sonicap on them for me

that reminds me of that post someone had put up of a picture of a really big cap with a small cap inside LOL.

Nightfall

Nice work, @westmassguy

Not that I've ever seen you post something that looked botched.

westmassguy

Thank you Sir

steveinaz

I would by-pass the tweeter level pot/board while you're at it.

westmassguy

steveinaz wrote: »

I would by-pass the tweeter level pot/board while you're at it.

Not my speakers. Up to the owner

drumminman

Interested in the before and after sound. I've never been a fan of that period of japanese speakers, but I've heard the HPM series was a cut above. The owner must think alot of them.

westmassguy

He does drummin. 35+ year old film caps, NP Electrolytics, and crap Resistors. It should be quite a difference.

steveinaz

I had a pair of HPM-40's that used to be in my 70's mancave---when I had a 70's mancave. Gave them to a close friend of mine. I still have my 1977 PRISTINE SX-780 receiver out in the shop providing entertainment.

vcwatkins

I liked the HPM-100's while they were here 4 or 5 years ago. I thought the HPM-900's were a tad better, but the difference might have been due more to crossover age than original components.

HPM-40's were my high school and college speaker. I recreated that college rig and later rotated in bigger HPM's and SX receivers, 980 and 1250. That was a fun little retro rig. #2 son used it for a couple years and loved it. Still uses the SX-980 for bedroom along with a PL-516 turntable.

I'd love to hear what those 100's sound like after the upgrade. Nice work, @westmassguy .

westmassguy

Thank you sir

steveinaz

vcwatkins wrote: »

HPM-40's were my high school and college speaker...

Sounds like we had similar tastes; I had the SX-780, HPM-40's, PL-516, and CT-F500 cassette deck. Ahh those were the days. Remember how cool FM stereo used to be? Being a native Saint Louisan, we had TONS of great stations on the FM dial.

...and yes, I HAVE a K-SHE 95 flag. LOL

michaeljhsda2

steveinaz wrote: »

vcwatkins wrote: »

...and yes, I HAVE a K-SHE 95 flag. LOL

sweet!

PolkieMan

I had a set from 1976-90, that's when I bought the 2.3 TLS. Got them at Custom HI-Fi in Houston for $186 each LOL

Joey_Ramone

Those are mine, glad to run across the post. Upgrade made a major difference in the 100's, all the range without the overly bright tone. Thanks for the great upgrade westmassguy! Running on a recapped SX-1250 with SG-9500 EQ. Was my favorite system in the house until I got the Spec Rack & HPM -1500's setup all restored. Working on restoring second Spec Rack to pair with a minty pair of otherworldly HPM-200's

westmassguy

Glad to help Joe. And a post on your Monitor 12s:
http://forum.polkaudio.com/discussion/167458/the-elusive-monitor-12#latest

voltz

Welcome to the Forum Joe!! Glad your enjoying those speakers.

love the Joey avatar pic...you need to show off your Vintage gear over in this other thread! super cool rack you have..
http://forum.polkaudio.com/discussion/133781/this-joint-needs-some-more-vintage-hifi#latest