Help with Acoustat Model 1 + 1

I recently bought a pair of Acoustat Model 1 + 1 with Hafler Mk121 transformers. I foolishly bought 'em without testing, and of course, the transformers were near-DOA, but I was able to get 'em repaired and the speakers working. However, I'm struggling with the following and would very much appreciate your counsel:
1. Am I best served leaving the transformers plugged in? Do they need to stay charged? They seem like an electrical fire waiting to happen.
2. I've been testing the speakers with a 150w/ch 80s HK integrated; high voltage/high current, but still need to crank the amp up to get decent volume level. Is it possible I'm underpowering even at 150w?
3. The Acoustat passive sounds marginal; will I encounter any special difficulty trying to integrate a modern powered sub?
Thanks in advance for your insights.
Hi, Acoustat and all other electrostatic speakers I know of should be plugged in all of the time. They take a while to sound their best after being unplugged.

I am not familiar with your HK amplifier, but I know electrostatic speakers are hard on amplifiers and very few solid state amplifiers sound good with electrostatic speakers. Your least expensive solution will be a used Acoustat TNT 200. This is a 200 watt per channel amplifier designed for driving Acoustat speakers.

Acoustat 1+1 did not come with a subwoofer and in my opinion does not need a subwoofer when powered by an appropriate amplifier. The 1+1 should have plenty of bass on its own. The Model 1 came with a subwoofer.
Yeah, I think the 1+1 does need lots of power and you should leave them plugged in all the time. If that bothers you, you might want to look for other speakers.

The Acoustat TNT200 should be more capable than your HK amp. I used a Hafler DH500 on mine back in the day and they were the only speakers that made the Hafler's fan kick up into the high speed. With the Acoustats, the larger models with more ESL panels per side were more efficient than the ones with only one or two panels each... so they played louder with less power.

You can run the Acoustats full range and dial in an active subwoofer using the sub's crossover and volume controls to match it to the Acoustats. If you want to roll the Acoustats off and cross the sub in higher, you will need an electronic crossover or a different set of Acoustat interfaces to accomplish that. But something like an inexpensive (used) Paradigm X-30 active crossover would do the trick.

On the other hand, buying a set of Tekton Lore-series speakers and powering them with a modest tube amp might give better results and they would not have to be powered up all the time...
rrog, plato, thanks for the feedback. per your suggestions i had a buddy come by last night with a 450 w/ch carver pro amp, which although hardly an audiophile-grade piece, made a huge difference--it's clear i was underpowering them even with 150 honest watts. (a bit disconcerting when plugging in the amp makes all the lights flicker, however). the extra juice markedly improved the sub as well. quite exceptional sounding overall--narrow soundstage but eerie realism, detail, etc. i would be curious to compare them to a less challenging, power hungry speaker like the tekton or maybe zu, but these acoustats certainly do justify their reputation.
I am using Maggie 1.7s and recently added a pair of JC1 amps. These are good for 800 watts! I had read even these little Maggies need lots of power but I was not expecting the improvement over the Cambridge Audio power amp I had been using, good for 350 watts into the four ohm load. So I suggest finding the most and best watts you can afford.

You may want to experiment with tubes driving your 1+1s, especially if you have a friend who will loan you an amp(s). They won't produce the bass that that giant Carver will, but that 3-D magic will likely get even better. I've had various Acoustats for 30 years, switched to tubes from solid state 10 years ago, haven't looked back.

klinerm, i'm surprised that tubes would have enough juice--what specifically are you running your acoustats with?
You don't need JL-3s to drive your 1+1s. A pair of Quicksilver Silver 90s will do just fine. One of the best amps I have heard on Acoustats is the TNT200. It was designed by Acoustat for Acoustat speakers and it sounded better than my Levinson driving 1+1s.
i appreciate the responses. first, an errata--i actually own the model ones (single panel w/passive sub), not the 1 + 1. in any event, i finally settled on a hafler 9500 amp. as i understand it, hafler based on the tnt200 design after he acquired acoustat in the mid 80's. thus driven, the acoustats are pretty great--they have that non-fatiguing, eerie realism that you only get with electrostatics. their main limitation is soundstage width--they have a definite, narrow sweet spot--which is not an issue in my 9' x 18' listening room. i often see these monoliths listed for near give-away prices (i assume most wives hate 'em), and while not for everyone they're an inexpensive entry to real high end.
I had MY Accoustats catch fire. I was luckily in the room when this happened, and quickly unplugged them, and returned the transformers to Accoustat for repair. I then sold them. I believe I was driving them with an amp called Ampzilla which was 200 watts a side. I don't remember the sound per se, but I remembered being pleased with bass problems that I can recall
Back in the 80's I had the Acoustat model three and drove them with a single Conrad Johnson (tube) MV 75A-1 and I used a Janus subwoofer,no longer made but some maybe around.

This was a nice sounding system,one of my favourites, but I moved on and went thru numerous stats and cones until I'm right back with a pair of 3 panel Acoustats, only this time with their own tubed servo amps.

I feel no need to use subs this time around.

The amps and speakers are fom the middle to late 1970's, the amps have been modded, but everything is left on,(standby)and no fear of fire etc.

If you are fearful,have a qualified service tech have alook at the Transformer/interfaces and if everything is fine, no problems, keep them plugged in and ready to go.
They sound much better when they've been powered up for awhile.

In case you grow tired of them and return to cones, just store the 1+1's, don't sell them.

You'll want to go back to them, so don't let them slip away.