TRL ST225 - Goodness anyone else own this amp

I will soon be writing a review on this amp and wonder if any fellow Agoners own this gem. If so, please let us hear your comments on it. I am nothing short of amazed by it. I had to "downsize" and sold a tube monobloc amp and tubed preamp combo costing over $15,000 new. Both pieces were fine sounding and well regarded.

I ended up trading a set of speakers for a TRL ST225 integrated amp. I had never heard of this amp before and was not aware of Paul's work.

All I will say for now is this integrated amp bested my previous set-up and is the finest sound my speakers and room have provided.

I am a tube guy folks and this SS amp is still the finest amp I have ever heard. I put $5000 in the bank and have better sounding music. Now that is exciting!!!

They cost some $5500 new and mine was purchased/traded as used. It had just been updated by Paul and came direct to me once the upgrade was finished.

Happy in MN

I am glad to hear that you discover this special gem. I have an opportunity to hear ST225 at a friend's in Philly driving a 3-way with a pair of 15" woofer. With Paul's expertise in design and manufacturing top tier tube gears, I think he manages to harness the 'tube' warmth and magic into a transistor design so that we can rip the benefits from both worlds coming in a SS box. I have been thoroughly enjoying my TRL mono's and have not being even tempted by any amp upgraditis as yet. I look forward to your review.

I've given Paul a deposit on the ST225. I heard this amp at a friend s' house. I couldn't give Paul my money fast enough. The chassis's have been back ordered and so I wait.
I would like to hear more. What equipment are you using.
Thanks Kim
With Paul and Frank here in the great North we are truly blessed.....I can't wait to hear his creations...cheers,Bob

You will just not believe how good this amp is. Forget the word downsize as it will be the finest amp you have owned. Music will flow and you won't feel like it's missing that or could do this other thing better.

It takes a few weeks to fully burn in and sound its best.
Mine is always on now and it runs cool all the time.

I want to let all Agoners know how wonderful this amp is. I have been containing myself as much as possible over the last few weeks, but must now spill out just a little.

Here is the plain truth based on my experience as an audiophile over the last 22 years. Please keep in mind I have owned and heard more reference quality amps/preamps then I care to list right now. I can say with 100% honesty that no preamp/amp combo has come close to being as good as this integrated. For me it is the first perfect amp or component I have owned.

My speakers never sounded this good at low volume. They have never sounded this good at moderate volume. They have never sounded this good at 105 db listening levels. No, they have always sounded like speakers, but now they sound like music.

I stumbled apon it as part of a trade. I had no idea what it was except the person trading with me told me it was wonderful and he is/was trustworthy.

I thought I was down-grading and saving money. I saved big money and upgraded like I have never experienced before.

This is not the best amp within a certain price point. It is the best amp period that my ears have heard.

Yes, I am sounding like an audio nut or some over zealous case. I don't care because it is true Agoners.

Ok, I let it out and feel good!

I will post a full review very shortly.

Love stories like this. Reminds me of the Supratek thread, and after hearing the Syrah in my own system, I agreed with what was said there. Bill, can you give us some examples of other amps/preamps you've owned, just to give us some context?
I have had the D-225 (non-integrated version of the ST-225) in my system for over 2 years now. It was Brian Weitzel's amp which was upgraded to current specs about a year or so ago (for free I might add). I am now using this amp with the TRL Pre-1.5 battery powered preamp. The combination is really amazing.
Dennis - the - menace - I love some of these usernames!

Here are some (just some of the best) of my past amp/preamp experiences at home.


Audio Horizons - My favorite of the bunch
Tom Evan Vibe
Thor TPA1000
Wavac - Forget the model #
Supratek Syrah
Supratek Cortese
Joule LA150


Canary CA339's - best of the group
Mcintosh 402
NuForce SE 9
JC1 monoblocks
Belles Reference 350A
Belles 350A monoblock amps
David Berning Z 270
Thor TPA30's @ 60's
Joule Vamp Integrated
George Wright 2a3 monos
Wavac SET amp 845 based - forget the model #
Monarchy SE250's
Several Blue Circle Hybrid amps
Butler Audio
Vac Musicbloc monos

Hope this helps.

woah... thanks bill. that helps a lot. i love my canary amps. awesome sound. very similar to the VAC, tho a bit more transparent and dynamic, maybe less warm, tho I'm warming them up w/ some NOS tubes. your list makes me want to audition TRL gear!
When I say this int amp is better please understand I don't mean by some small margin. It has utterly transformed my music and my audio experience like no other piece of gear.

After "playing" with so many great amps I figured no system could ever really sound that much better - perhaps a little different or one aspect better here ......

No, the TRL ST225 broke through a plateau I thought was not possible or available in audio reproduction.

I wish more Audiogoners were reading this thread as many more people would be amazed and smiling like me.

I had Van The Man in my listening room last night as I listened to his live recording "A Night In San Fran" I was lost my friends - lost in the concert.


I can feel and understand your excitement. I've owned a TRL ST-225 since June or July of 2005 and have even added a pair of their 500 watt battery powered mono blocks, after hearing Howard's (Hchi) before they left TRL.

I even wrote a review back in August of 2005, if you look in the archives.

There are several of us who have had issues posting a reply in this thread, but if you e-mail me, I can send you contact info of other TRL ST-225 owners, who have stories just like ours.

Understand and have had the pleasure of emailing others directly. I am ordering a modified Sony CD player from TRL as I am just floored by Brian & Paul's work.

Take care,

What company is this?? I find no TRL listed in A'gon directory.

What power cord are you using with the ST-225? If you're not already using one have Paul build you the Silver model he sells (for the CDP as well). It uses the same solid core copper wiring as in the amp. Great synergy and I use one on the D-225 and Pre-1.5. You won't believe the price to performance value.

In moving to Las Vegas recently the movers lost one of my boxes. Unfortunately in it were my pair of Silver model speaker cables Paul made for me. It's a tough loss to swallow, but at least the PCs made it.

Check under Tube Research Labs. However, not much on the website. Best to give Paul or Brian Weitzel a call directly.

I am also getting one of his power cords for the ST225. Don't need one for the CD player as it will also have his battery mod. I don't think a power cord will matter on his fully modified Sony with battery?

Like to hear your comments on this.



If you are getting the battery powered Sony DVP NS900V, unless I am not recalling correctly or the design changed from when I ordered mine only the analog stage is battery powered. The digital circuit still requires AC power. You may want to check with Paul or Brian on this.

I never got to listen to my battery powered TRL CDP. It was damaged in shipping and I then decided to trade it in towards the battery powered Pre-1.5 preamp. Brian recommended the Silver model PC as he said Paul voiced the preamp with this cable.
Actaully, the battery power supply for the Sony 900 also feeds the 5 volt regulator that supplies the digital board. I believe that the only sub component powered by the unit power cord is the 3.3V that drives the transport motor.

Brian or Paul would know for sure. Either way, the TRL silver series power cord makes a difference, even with such limited use. (To just drive the transport motor)

Bill: How many hours on your amp since you've recieved it? Just curious if you've experienced much break in?
Yes it now fully broken in. I did find improvement over a 150 hour burn in time. I played it 24/7 for a week and have been listening for another 6 weeks or so.

I say the amp now has over 300 hours on it.

You are correct about AC power running the display and motor transport.

I searched the Tube Research Labs website and I couldn't find any info on this ST-225 integrated in the product category. I think it retails for @ $5,500.00. Grannyring, what speakers are you currently driving?

In TRL's case you just have to pick up the phone and call or shoot off an email. Paul is very responsive. The TRL website isn't all that well maintained and lacking in updated information. The solid state designed gear is a relatively new venture within the last few years. Those I know that have either the ST-225 integrated, dual mono amp version, or mono blocks have been extremely pleased. Paul's new tube preamp design is supposed to be killer as well.
I'm surprised that if this ss integrated is really this good that the makers would be promoting it somewhat.

I so understand your thinking on this. I owned the AH preamp you have with $14,000 Canary CA339 tube monoblock amps. These tube amps tipped the scales at 70 pounds each with 8 - 300b tubes pushing out 50 glorious tube watts per channel. Many think these Canary amps are among the best amps one can own.

This ST225 int amp so utterly surpassed these previous components that it shocked me. I can't say it any clearer then already mentioned above in my various posts. If folks don't and can't believe it, then that is unfortunate.

I repeat, this is not some slight improvement here or there, but another realm, another level of live music playing in my room.

Sherod, I have no reason to overstate the reality of this gear. I have no agenda. I would have never thought gear this good was even available - at any price. I had come to the place where I thought most top end gear all competed on a similar level with only slight differences.

This amp has changed all that.

I can't explain why this amp is not more heavily promoted. What I do know is the ST225 amp will open your audio and music world to levels you never thought affordable or possible. This is the truth of the matter.

If I did not have this amp in my listening room, I may have pushed aside this thread. I understand. Many folks say many great things about new audio products. Posts like this one are everywhere. I understand your comments.

I have owned much great gear and have some credible experience behind me. I stand behind every word I have said with passion as this amp is a must find for many more Agoners.

Oh well, yes I am excited about this amp.

I don't doubt that you believe this amp to sound as good as it does. I am very happy for you that you were able to find such a good-sounding integrated that you feel surpasses much more expensive equipment. Because of your enthusiasm, I would be interested in some day trying it out. At the moment, I am very happy with my all tube set-up, but it's good to know that should I feel like moving to an all solid-state integrated, this TRL ST225 integrated will be at the top of my list to look at. By the way. What speakers are you driving with this new amp? Also, if you could post a photo of this unit, I'd love to see what it looks like, both inside and out.
Not sure how to post a picture on this thread? Can't open up the unit as the allen screws are stripped out to keep folks from peeking in and trying to copy his work. TRL would have to do that. I don't know much about the unit and really have not concerned myself with it as it just sounds amazing.

No remote, dual mono build, 80 pounds, left and right volume knob, 3 inputs, dead quiet, never even gets warm, stays on all the time.

I own Dali Grand speakers. I have owned them for 5 years. I tried the new Helicon 800's plus several others as the upgrade bug hits, but each time the Grands came out on top.

I still own Joseph Chow's wire and find it to be very good for the money.

04-18-08: Grannyring
Can't open up the unit as the allen screws are stripped out to keep folks from peeking in and trying to copy his work.

That's thorough.

If a fuse needs to be changed inside (if there are any), does this mean you have to send in the unit to TRL?
I am really not sure why the top screws are stripped, but if anything goes wrong the amp would need to go to TRL.
I suppose one could cut a slit and then use a flathead to remove the screws.

Not sure if all units are that way or just mine.

I have no idea if the unit has fuses or not. I know there is a 12(or so) point protection circuit that handles any potential issues. The amp will shut off (one channel) if a problem is detected.

I understand these units are problem free and way overbuilt in the first place.

Lots of folks are emailing me with questions on this amp. Please call TRL as I really know very little beyond the way it sounds. I am sure Paul and Brian can and will help you. They do answer the phone which is so rare.

If someone can tell me how to "post a picture" here I will for those who would like to see it.


My D-225 is also "sealed" but not my Pre-1.5 preamp. I believe in addition to being stripped the screws are also epoxied. Trust me, I've tried to open this thing and its not going to happen. Instead I just sit back and enjoy it now.

Mine has been problem free. Some tidbits I've been able to collect: The power supply is way overbuilt. The transformers are designed by Paul and he has them wound to his own specs as well. Computer grade capacitors are generally used. Paul uses his own choke filter design. The switches are typically Shallco 45 step attenuators with Roederstein resistors and the input selectors are usually Shallco as welll. However, I heard at one time Paul was designing his own so its possible that these are the ones used now. Instead of a typical on/off switch a high quality breaker switch is used. Internal wiring is solid core copper. Not sure about the amp, but on my preamp the internal ground wire to the IEC is not connected. I suspect this is true of the amp as well as it appears to be something consistent in Paul's designs/mods. Cardas binding posts usually my preamp uses Cardas RCA.

Paul has never been a fan of negative feedback so this is a NFB design. While listed at 225 watts (not sure if its RMS or per channel, I think the latter) its closer to 300 watts. My chassis is black and made from steel, but I think some may be the newer aluminum ones (I had custom rosewood side panels made for mine). The dual volume control knobs are usually wood (mine are purple heart) and over sized and the dual input selector knobs brass.

Other than that it just sounds real good. I'm using mine right now with a pair of Audiokinesis Stormbringer speakers after having used it with Spendor 1/2e speakers for the last couple of years.

Yes, the amp is rated at 225, but Paul did say it puts out closer to 300 watts per channel. I have owned monoblock amps rated at 400 watts per channel that can play very loudly. What is special about the ST225 Int amp is even at sound pressure levels of 100db+ the music is not loud in a "headache" way.

I was listening to a live CD of blues/Jazz/Rock at db levels exceeding 105 (I don't do this often) and the music from highs to lows maintained perfect balance with no portion of the sound spectrum suffering. Same perfect balance found at low and moderate listening levels. The music simply grew in size, scale and impact. No hint of distortion, compression or shrill highs. Just perfect tone from top to bottom. This is the first time I have experienced such sonic perfection at 105 db.

The notes seem to float out into the room and swell in size and impact as I turn it up. Many SS amps "fire" the music at you.I notice this especially at loud volumes. Many tubes amps compress and start to get muddy in the bass and shrill in the highs.

Another thing I notice and enjoy all the time is how "take notice" muscular the amp is. No matter what I listen to, guitar & piano solo, Jazz, vocals, rock etc; the weight and flesh are simply awesome. The body of the instrument, the body and soul in voice, the weight and power of bass notes quick and sustained all cause me to take notice in amazement.

I can listen and do listen to music for hours with no hint of fatigue. Again, perfect tonally at ALL volumes.

Having fun,


You described the sound quite accurately. Seems you've become quite acclimated to the ST-225. Glad to hear you are enjoying it. Now just wait until you hear the CDP with it.
Based upon my recollection of conversations with Paul, I don't think the amps have fuses in them, but circuit breaker switch only. Besides the full spectrum tonal balance Bill experienced, one among other things that impressed me is the "density" of the sound "images" in the stage that the amp is capable of casting. I am lucky to hear some very good setups of a few top amps (i.e. Gryphon, Jadis, Goldmund, ASR, Halcro, DartZeel, Kondo, etc) at various friends' dwellings. Personally, my TRL amps have never disappointed. For people seeking truthful, distortion-free, grain-free reproduction of music, IMHO TRL amps should definitely be on the short audition list before purchased.
Just pulled a past email from Paul about never using fuses in his own designs, but circuit-breaker switches for the reason yielding much better sound. FYI, here is the spec I have collected about the amp:

Input Impedance: 68kohms
Input Sensitivity: 1.1Vrms
THD: < 0.05%
Gain: 30db
Noise Floor: < -100db
Rail Voltage: +/- 76 VDC
Power: 225 watts
Power consumption: 600 watts
Your right Howard, it has been known for years now that fuses are not the way to go . Hopefully, someday the others will catch up.
Paul told me the gain on my amp was about 37db and input sensitivity .8V. I would have to agree with the gain number as most preamps I used with this amp could not get past 10 o'clock on the volume control before reaching my preferred listening level (about 90db or so). Only exceptions were the K&K Audio TVC and the TRL Pre-1.5.

On the power consumption I find the number interesting. I once had an Exact Power EP-15A. With this component as you plug gear into it the display tells you how much power consumption is being utlized. I plugged in my DAC and transport and the display read 30 watts. When I plugged in the amp I expected an increase along the lines of 500 watts or so, but the display increased to 45 watts. On occasion it would rise to 60 or 75 watts when I was playing music. I thought there might be something wrong with the EP-15A so I called tech support at Exact Power. They had me run a simple test. They asked me to get the power consumption rating for my TV and then plug it in to the EP-15A. Sure enough the display jumped up 150 watts, which was the correct power consumption rating.

I'd like to know the slew rate and damping factor of the amp. However, I've learned that Paul eschews specs when designing and relies on his ears much more.
I was listening to great music tonight and am so thankful for this amp. Natural is the word of the night. Music flowed so naturally and easy.

Every CD I play just gets my full attention.

I keep my amp on at all times and have not noticed a larger electricity bill? Can't be pulling that much juice from the wall? The amp is never even warm to the touch.

Paul did confirm the amp uses no fuses as they degrade sound.

You're going to get spoiled not having to replace tubes any more. Just imagine the long-term savings. Adios to tube rolling. (O:
Yes, tubes are a thing of the past for me in my main system. I may play with a small tube based system for my bedroom someday.

An excellent tube circuit design would yield the liveliness, sound stage, layering, and ambient decaying that many ss designs still come short of. In contrast, an excellent ss design has bass extension, impact, dynamic, and transient attacks that many tube can't quite match. That's why I have been preferring the ss amp and tube pre combo. The ss amp design gives me the luxury of having it turned on 24x7 and not worrying inability to drive difficult-load speakers. Because of TRL extreme low noise-floor, grain-free nature, it makes matching higher sensitive speakers possible also (heard ST-225 with 90+ db speakers before). The tube rolling at pre gives me that flexibility of adding a touch of warmth and improve liveliness without sacrificing (much) neutrality and full spectrum balance. I have no complaint but prasie for my TRL monos. The high gain amp design makes finding a matching pre a bit tougher. However, that's the inconvenience I am willing to go through considering the musical fulfillment the amps have brought for thus far. :)
Grannyring: Thank you for your post. I was considering 2 of the amplifiers within your list and you may have just saved me thousands of dollars. I have been in contact with one ST-225 owner and plan on visiting him in a week for a listen. He also has the TRL 3 ways, TRL cabling and their modified Marantz SA-8001, so I feel that I'll have a good idea as to their house sound.

Hchi: How much does the battery power supply help? Is it worth the extra money? How much room does the battery power box require? I'm assuming they are sealed batteries, so no smell?

Glad to read your comments! I have ordered the battery operated Sony player from TRL and expect in in a week or so.

Wow, Terryn that's quite the find for your total enjoyment. Can't wait to hear what you think of that rig ! Hope it's in a decent size studio. The speakers alone are worth their weight in precious metals. The metals seems to be the only thing that is worth much in the states nowadays.
Terryn: I think the battery PS takes it up to a different league. I won't hesitate if I could do it over again. The batteries used are the seal, deep-cycled ones. Since my mono's are customized units, they come in as a 4-piece configuration. However, I don't think this is standard. If memory serves me right, Jack's battery chassis comes in 24" x 12" x 12" military metal ammo case. Users have the freedom to use the amps with and without the battery. With the battery turns on, the noise-level drops further, the soundstage expands, the weight and the "density" of the sound images improves, everything just gets taken up a couple notches or more. It is not as much as an arch-welder like GT-800; luckily none of my speakers runs around 1 ohm, so I don't need it. Sonic-wise I believe it is the best that Paul has to offer (for now). :)

Litho: I'm sure that the price of lead has something to do with the price of the battery power supply.

I'll be calling TRL today to ask about the battery power supply; what size box and price. Comments from you that have heard the battery supply? TRL said earlier that it was "night and day" difference.


The GT-800's went retail for $140.000, not very many of these units in existence today. Paul has been a tube circuit designer for over 30 years. He currently has the battery powered amp. That amp will run neck and neck with the GT-800's. The battery powered amp is unsurpassed in any other transistor circuit known to man today. It is an amazing amp! Consider it seriously before our precious metals get of of reach for the common man. It will be the last amp you will ever buy, and the standard for others to reach.
I have the battery power supply for the Pre-1.5 preamp. I hope to some day get the battery power supply for the D-225 amp I have. In the preamp the batteries are housed within an ST-225 chassis. So that is convenient. The preamp is biased for Class A operation and if I recall runs at about 44 volts. In order to maintain a constant 44 volts the battery needs to be run in trickle charge mode. You can run it on complete battery mode but as the voltage drops and the bias moves from Class A down so does the sound quality, but it is still quite listenable. Bass becomes a bit more flubby for one thing.

I'm amazed at the transparency and detail of the TRL combination. At the same time it is extremely musical. In the right listening room the soundstage is huge, but not exaggerated like in some systems I have heard. The amp can handle any speaker load effortlessly. It never runs hot and the power supply is way overbuilt. I plug it straight into the wall now and it is dead quiet. I have tested it on a number of occasions with the inputs shorted and speakers connected. No hiss, hum, not a peep.
Okay, it is set. I'm going to hear the TRL ST-225 this coming Saturday. I'll report back.
Terry: Please find out if the owner has the new CRL interconnects. I'm anxious to hear what you think. They are suppose to be very reasonable in price, although I don't know what they are selling for currently.
Lithojoe: The new CRL isn't Weitzels design. I have a friend who tried the new CRL and he sent them back. Does Paul have a new cable?
Just received my TRL modified Sony 900 player. I got the full blown mod with battery option. Very good indeed. I will let it burn in 24/7 for another week before a say much more.Great combo with the ST225. I also have Paul's power cord on the ST225 now.

I am very happy with both the amp and cd player and cannot imagine moving away from these units for a long, long time.


Any comments for us on the ST225?

I just purchased the TRL D225 that was listed here on A'gon. I was kind of surprised that it was still available, it had already been listed for 9 days when I bought it.

I haven't heard the amps, but am familiar with Paul's work. I owned a Sony 900 modded by TRL [shouldn't have sold it], I still own TRL power cables and a TRL modded power strip.

Based on my experience with TRL and seeing the comments above and the list of amps that the TRL bested, I'm very excited to hear the D225 in my system. I imagine it will have no problem outperforming my Belles 150A Reference.

I'm hoping it will be the last amp I buy!
Just a quick update on the D225.

Keep in mind the amp is essentially brand new and not burned in at all.

There is no part of the spectrum that is exaggerated, it is smooth from top to bottom, like I haven't heard before. Even at really low volumes the amp sounds full. It sounds the same whether I'm at 1/8 volume or 3/4 volume, just louder or quieter. More so than any amp I've ever heard. The Nuforce Ref 9 V2 was the previous best I'd heard at this. The D225 blows it away.

This amp is absolutely, positively, dead quiet! Like, amazingly quiet. Like I have never really heard a quiet amp before in my life, quiet. Maybe because it's so quiet, details come thru like I've never heard before. By detail I don't mean the typical, more treble, etc, I mean, background sounds, breaths, movements on instruments, the recording environment. On Jason Mraz's I'm Yours, which I listen to all the time, at the beginning of the song there's the sound of waves hitting the shore. I've never heard any hint of these before, but with the D225 they were as clear as day. On Jack Johnson's Banana Pancakes, in the beginning there is the sound of rain falling. Normally it sounds like a little trickle in the background. When I listened to it this morning, I actually paused the song because I thought someone had turned on the water in the bathroom above where I was sitting. That's how pronounced it was, it sounded like it was literally raining out the window.

At this point, I've only listened for a couple of hours total, so that's all I have for now. But it is clear this is the best amp I've ever heard and it's not even burned in yet.