Mods for Hsu STF-2??

dlparker · « **on:** 2 Oct 2014, 11:27 pm »

I've been wanting to upgrade my sub for a long time (Hsu STF-2 - nice little unit).

Questions just for starters:
#1 - what 10" driver would be a good replacement for the stock one
#2 - is there a servo-amp that's plug and play with the stock bash amp?

I'm not going to be able to do this for a while, so if this generates any discussion I'll jump back
in with cabinet interior treatment questions.

If I ever get this off the ground to the point of treating the exterior of the cab I'll feel like I'm seriously
ensconced in fat city..

Danny Richie · « **Reply #1 on:** 3 Oct 2014, 01:15 am »

It might be a better plan to start over than to upgrade parts and pieces.

The servo amps have to be used with the servo drivers. They can't be mixed and matched with other drivers and amps.

PMAT · « **Reply #2 on:** 3 Oct 2014, 06:31 am »

The HSU is just fine as it is for what it is. Leave it alone and sell it to buy a more substantial unit. All kinds of great ways to go.

PMAT · « **Reply #3 on:** 3 Oct 2014, 06:43 am »

I sold mine a while back for $250

dlparker · « **Reply #4 on:** 3 Oct 2014, 07:02 am »

Quote from: Danny Richie on 3 Oct 2014, 01:15 am

It might be a better plan to start over than to upgrade parts and pieces.

The servo amps have to be used with the servo drivers. They can't be mixed and matched with other drivers and amps.

There's no 10" servo driver? I'd start with the driver because I think the amp is in the $400/500, range, right? I thought I
read a reference to a 10" servo driver somewhere.

mlundy57 · « **Reply #5 on:** 3 Oct 2014, 11:11 am »

Quote from: dlparker on 3 Oct 2014, 07:02 am

There's no 10" servo driver? I'd start with the driver because I think the amp is in the $400/500, range, right? I thought I
read a reference to a 10" servo driver somewhere.

You may be thinking about a post I made awhile back about one of my subs. It's an older Von Schweikert VR-S1. It is a servo controlled sealed sub with a 10" down firing driver.

However, it is not the direct servo control of the Rythmik/GR subs. Also, it has been out of production for a few years.

Mike

Danny Richie · « **Reply #6 on:** 3 Oct 2014, 01:55 pm »

Quote from: dlparker on 3 Oct 2014, 07:02 am

There's no 10" servo driver? I'd start with the driver because I think the amp is in the $400/500, range, right? I thought I
read a reference to a 10" servo driver somewhere.

Currently there are no 10's.

bdp24 · « **Reply #7 on:** 3 Oct 2014, 09:32 pm »

Besides which, the Servo drivers (8" and 12") each need a specific amount of enclosure volume, which your HSU may or may not possess.

dlparker · « **Reply #8 on:** 3 Oct 2014, 09:53 pm »

Quote from: bdp24 on 3 Oct 2014, 09:32 pm

Besides which, the Servo drivers (8" and 12") each need a specific amount of enclosure volume, which your HSU may or may not possess.

Okay. Back to an earlier 'plan' of mine - keeping in mind that by 'plan' I mean
totally random musings based on no known scientific or engineering principles.

Two 8" servo subs and amp in a sealed enclosure for starters (one unit). Basic,
utilitarian, man-cave beast to sit wherever he needs to go, with an eye toward
expanding that prototype into a portable system for a PA to include some
configuration of LGK drivers for small portable PA system. LGK & sub in sealed
enclosures with the ability to be somehow wrapped or otherwise protected for
frequent transport and handling by people who may or may not care about the
physical and electrical integrity of the unit.

The first unit is office/studio/main stereo listening system, which I'll probably upgrade
with the affordable accuracy monitors. Right now I'm using a pair of the stock BS-22
speakers that I modded with the tweeter/cap replacement. Love 'em.

I'll stay with that for a while, at least until the 'holy crap' phase is over and I'm back to
just listening to music.

If I EVER get my act together - on at least a personal and professional level and probably
numerous others - I'll start on the PA project, and hopefully be able to expand it into a
modular system similar to the Phil Jones Pure Sound LS mains/monitors and W subs.

Captainhemo · « **Reply #9 on:** 4 Oct 2014, 04:09 am »

Quote from: mlundy57 on 3 Oct 2014, 11:11 am

You may be thinking about a post I made awhile back about one of my subs. It's an older Von Schweikert VR-S1. It is a servo controlled sealed sub with a 10" down firing driver.

However, it is not the direct servo control of the Rythmik/GR subs. Also, it has been out of production for a few years.

Mike

Ok, I should probably know this (but I don't) as I now have the H frame/SW12 16FR's.... what is the difference between direct servo controlled sub and just servo sub ?

-jay

dlparker · « **Reply #10 on:** 4 Oct 2014, 04:18 am »

Quote from: Captainhemo on 4 Oct 2014, 04:09 am

Ok, I should probably know this (but I don't) as I now have the H frame/SW12 16FR's.... what is the difference between direct servo controlled sub and just servo sub ?

-jay

God forbid that not knowing the answer should prevent me from answering. It's never done it in the past. But I'm going
to show at least SOME restraint and proclaim loudly that this is only a guess.

They're synonymous?

Danny Richie · « **Reply #11 on:** 4 Oct 2014, 04:40 am »

The older servo control system were accelerometer based. They were not bad but don't have the control or reliability of the patented direct servo systems from Rythmik.

And by reliability I mean some of the accelerometers would fly off after a while.

dlparker · « **Reply #12 on:** 4 Oct 2014, 04:52 am »

Quote from: Danny Richie on 4 Oct 2014, 04:40 am

The older servo control system were accelerometer based. They were not bad but don't have the control or reliability of the patented direct servo systems from Rythmik.

And by reliability I mean some of the accelerometers would fly of after a while.

As in physically fly off?

Danny Richie · « **Reply #13 on:** 4 Oct 2014, 05:17 am »

Quote from: dlparker on 4 Oct 2014, 04:52 am

As in physically fly off?

Yes, they would come off.

dlparker · « **Reply #14 on:** 4 Oct 2014, 05:20 am »

Quote from: Danny Richie on 4 Oct 2014, 05:17 am

Yes, they would come off.

Bet that generated a youtube video or two..

dlparker · « **Reply #15 on:** 10 Mar 2016, 05:51 am »

More questions on the Hsu STF-2 sub. Just got mine back after having sold it (I thought) on eBay. The plate amp is now not working, but the speaker is fine. I'm trying to find a replacement plate amp at a reasonable price. If I do find a suitable replacement, I'm thinking about replacing the polyfill (I think that's what it is) damping material with no-Rez. Will this improve the stock STF-2 at all, or am I just as well off leaving it as is and replacing only the plate amp?

Also looking for replacement floor spikes. They were not returned with the unit. Does anyone have the thread specs on the spikes?

drewm · « **Reply #16 on:** 10 Mar 2016, 07:09 am »

Quote from: dlparker on 10 Mar 2016, 05:51 am

More questions on the Hsu STF-2 sub. Just got mine back after having sold it (I thought) on eBay. The plate amp is now not working, but the speaker is fine. I'm trying to find a replacement plate amp at a reasonable price. If I do find a suitable replacement, I'm thinking about replacing the polyfill (I think that's what it is) damping material with no-Rez. Will this improve the stock STF-2 at all, or am I just as well off leaving it as is and replacing only the plate amp?

Also looking for replacement floor spikes. They were not returned with the unit. Does anyone have the thread specs on the spikes?

You'll probably want to call HSU for the amp as the plate is probably a custom size, unless you plan on running an external amp. Or have an electronics person figure out what component blew.

dlparker · « **Reply #17 on:** 10 Mar 2016, 09:39 am »

Quote from: drewm on 10 Mar 2016, 07:09 am

You'll probably want to call HSU for the amp as the plate is probably a custom size, unless you plan on running an external amp. Or have an electronics person figure out what component blew.

I haven't heard back from them yet, but that would not surprise me. And the electronics are undoubtedly customized to the specifics of the cab/speaker.

Doublej · « **Reply #18 on:** 10 Mar 2016, 03:14 pm »

I am surprised given the number of failures of subwoofer plate amps that there isn't someone out there who has figured out what the most likely root causes are and then created a youtube repair videos.

In answer to your direct question, I have seen recommendations for using a best fit Parts Express subwoofer plate amplifier and making cabinet adjustments. I think there are a couple of threads on this topic on the Hsu support forum.

Good luck.

dlparker · « **Reply #19 on:** 10 Mar 2016, 05:05 pm »

Quote from: Doublej on 10 Mar 2016, 03:14 pm

I am surprised given the number of failures of subwoofer plate amps that there isn't someone out there who has figured out what the most likely root causes are and then created a youtube repair videos.

In answer to your direct question, I have seen recommendations for using a best fit Parts Express subwoofer plate amplifier and making cabinet adjustments. I think there are a couple of threads on this topic on the Hsu support forum.

Good luck.

Thanks. I looked at the back of the plate amp and decided pretty quickly - klutz that I am, that it was pointless to try and do anything with the amp. I'll check the forum.

Still curious about the no-rez, though. I figure while I've got it open I might as well line the interior of the cab with it.