Review: Antique Sound Labs Flora EX DT Line Preamplifier Tube preamp

Category: Preamps

Before I get to the review of the Flora EX DT Linestage I would like to share some background information regarding my year long odyssey doing home auditions of some very highly regarded tube based linestages. The reason for this to give a context of what I was looking for when listening to these different pieces.

I had lived with to great passive preamps, that had replaced a ML-32 reference, the Placette Active(buffered,no gain) and Bent Audio's great transformer based Tap linestage for the last three and a half years. My personal taste for certain audio "flavors" would be reflected in the choice of a TVC passive linestage:

1) An absent noise floor were music just floats out of a black background into my listening space.

2) Natural timbres, I listen almost completely to acoustic jazz, so I want trumpets to sound brassy and a bass fiddle to sound different then an electrical bass.

3) I find clarity/transparency very important and believe it is an important aspect for allowing leading edges of notes and microdetails to be present in the music.

4) Full extension of the top and bottom, and that the lower bass be quick and not "plumy" or rich and fat.

5) Layering in the sound stage with "air" around the players without bloating the players into oversized cutouts.

I thought it was important to share what I'm looking for sonicly in a linestage, along with system synergy, because the three linestages I auditioned have recieved stellar reviews and other GON members I'm friends with have them in their systems and love them. So, are we clear, no "shoot out" or the best with a capitol B, just a perspective of how the Flora sonicly fits in with this group of linestages.

So, I was very curious if I could keep the sonic virtues of my beloved TVC based TAP and get some of the "magic" that tubes can offer at the same time. Here's a brief rundown of my experience with these different pieces.

1) Shindo Labs Monbrison-Found this linestage quite average in its performance. Did nothing very good or very bad in my system. It was OK but not better in any way then the TAP, yet it was more then $4000.00 above the price of the TAP!

2)Joule Electra 150 MK2- This linestage was just given a golden ear award by Harry Pearson. In my system it offered what I would call a overly "lush" sonic perspective that put my system to sleep. It also had a very apparent lower midrange or upper bass "hump" that I found annoying as time went by.

3) Modright 36.9- This linestage almost won my sonic heart because it offers many of the sonic attributes I was looking for, however it fell short in two areas compared to the TAP TVC. It was not quite as transparent as I was used to, but quite close. It was wonderful at not being "fat" or over the top with warmth, but was great with the body and decay trails of notes, but fell a little short with clarity on the leading edges. Almost a keeper!

Well, I decided that active tube linestages just were not my cup of sonic tea, and then I read on some website about this very different linestage that was active but used autotransformers like a TVC, but used one active tube based gain stage, before finally going back into a transformer-coupled output stage. Maybe, the best of all possible worlds?

The ASL's Flora EX DT linestage is a massive large black box, it's weight is 35 lbs.,and is very well built. It's surely not "eye candy" but its not exactly an "ugly duckling" either. You can reverse phase or mute either from the remote control or on the front of the Flora.

As far as what makes this linestage unique from a design veiwpoint is the following. The absence of any type of potentiometer volume control. Instead it uses a autoformer/switch-based input stage, into a single triode gain stage, and finally to a transformer-coupled output.

The importer highly recommends, a ASL installed mod of Mondorf capacitors to replace the standard large coupling caps. I ordered mine with this upgrade, cost $250.00, along with replacing the two tubes sourced from China with two NOS Sylvania 6SN7WGTA 1958 Chrome Domes.

Well, not only did the flora give all the sonic virtues of my Tap TVC that I mentioned at the begining of the review , but it added the following:

1) The most remarkable sound stage with the greatest depth I have ever had in my system, but with 3-D sense of a "air" around each player and layering that was precise and natural.

2)The best timbres/tonal accuracy of any preamp I have ever listened to.

3) My whole system became more "alive" and dynamic yet at at the same has more liquidity then ever before.

4) On macrodynamics the sense of scale/attack is very lifelike and yet the body of notes is still full with wonderful decay trails.

Wayne Donnelly reviewed the Flora on www. Enjoy the music. com and just gave it a Best of 2007 Award. Here's his explanation of why this $3000.00 linestage competes with mega dollar pieces out their today.

"Its sound presentation is tonally accurate, harmonically complete, and outstanding in creating a broad deep spatial rendering of the recording, with startling degree of palpability and precise location of voices and instruments within the sound scape.... the best-sounding preamp this writer has heard. In fact much of the Flora's real competition comes from top models in the five-figure price range."

The flora is my new reference linestage. I would recommend that anybody looking for an active tube based linestage consider it for audition, I consider it a bargain even with the CAP upgrade at its $3000.00 price. Remember I did not say it is the BEST linestage, but a terrific one that is on the same level as world class reference pieces at a very reasonable price.

Associated gear
Click to view my Virtual System
A very tasty review! Clearly stated system goals, well written, drew me into it, made my mouth water for the Flora! I looked at a photo briefly and it looked like there was one set of XLRs. I assume you are running yours SE? How about listing some cool acoustic Jazz cd's? I am looking to expand my music collection in that direction. I just ordered some acoustic blues (Buddy Guy / Junior Wells). THis is the kind of music that makes the rig sing!
teajay, I am intrigued especially given the price. Can you clarify, what ins and outs it has? Does it have truly balanced inputs and outputs? As Dpac996 mentioned, there appears to be only 1 pair of XLRs on the back. Is this for in or out?
Thanks for your well written and structured review. The Flora has definitely caught my eye as a potential purchase. Hope it continues to give you listening pleasure for a long time.
Teajay- Enjoyed the review- good job.
First, thanks to Dpac996, Photon46, and Danlib1 for your kind words regarding my review. On to the questions that you guys and Tboooe asked.

1) The Flora has one set of XLR'S for input.

2) The Flora has four single ended outputs.

3) Yes, I'm running it Single ended.

4) Don't know if its truly balanced either input or output, if you give a call to Tosh, the North American distributor, at 519-749-1565 I'm sure he can answer this question. He's quite a gentleman and helped design the Flora, so he can answer any "tech" questions you might have.

5)Dpac996, try these two of CD's. Kenny Burrell's Midnight Blue and Lee Morgan's The Sidewinder both on Blue Note records and both are classics offering blues oriented/ hardbop at its finest.
Teajay, so how long the TAP was actually in your system? Also, have you tried Pass Labs line stages with your amps?

Flora looks cool and looks to be well built.
Based on how impressed you are with it, it makes me curious to audition it, but at this point it seems like the only way to do that I will need to buy the Flora.

BTW, what are you going to do with TAP? Did you sell it?
Audphile 1, here's the answers to your questions:

1) The Tap was in my system for nine months.

2) I have always been a fan of Nelson Pass regarding his amps, but less so his linestages. I think the current linestages are quite nice, but not at the same level as the Flora.

3) You can set up an audition with Divergent Technologies, 519-749-1565, there is a re-stocking fee and you pay for shipping it back if you decide not to keep it.

4) My beloved TAP was sold in less then 12 hours after I posted it for sale here on the GON. It really is a great TVC, and only was bettered by the Flora in my system.
I wonder how Flora would compare to Placette Active ?
Elberoth2, without bad mouthing a piece, the Placette Active linestage, that was my reference for over three years, the Flora is on different higher qualitative level sonicly then the Placette Active.

If you go back to my review of the Bent Tap TVC it will explain why I thought the Tap was better then the Placette Active linestage in my system, so I replaced the Placette with the Tap. Well, you know were I'm going with this, the Flora was better then both in the context of my system and is my new reference.
Hi Teajay, Thanks for the great review. Do you know the output level/impedance of your DAC and input of your amp? As you know, any passive device will work at its best if it happens to be perfectly happy with the source ahead of it and the amp down the line. I'd like to compare your situation with mine to get an idea whether the Flora might work in my system. Thanks!
Joel, I don't know exactly what the output level/impedance of my Accoustic Arts DAC is, but if you go to their website that information is listed there. Also, I go into a Bryson X-over so its mute what my Pass Labs XA-100's impedance is.

I'm a little confused, the Flora is an active linestage not passive even though it uses autotransformers for its volume control, so your question regading its use in your system would not be relevant, just your personnal taste and system synergy.
Teajay, thanks for your response. I guess I was the one who was confused because I understood that the Flora was a passive device--I misread the point on the triode gain stage. Thanks for setting me straight. I'm still looking for the right passive stage for my system... Cheers.
Teajay, thanks for your response. I guess I was the one who was confused because I understood that the Flora was a passive device--I misread the point on the triode gain stage. Thanks for setting me straight. I'm still looking for the right passive stage for my system... Cheers.
Teajay, thanks for mentioning Kenny Burrell's Midnight Blue. I had not listened to it in quite some time - it is a classic.
When are you going to let me borrow it overnight? Bob
Baranyi, it was great having you over today to listen to the system with the Mullards in the DAC, to get your take on these tubes. Not only are you a fine gentleman and somebody I consider a good friend now, but boy you hear everything with those golden ear's of yours and are quite talented at being able to put into words precisely what you hear!

So, yea we will make arrangements for the Flora to spend a night over at your house sometime in the future.
Teajay, I heard the Flora at RMAF last month. . . very impressive indeed. My Toronto friend Chris (Frontier1) has shortly after ordered a Flora based on my admittedly far too quick impressions and your fab review. I was also delightfully surprised that the Flora looks quite substantial, and is a handsome piece of industrial design to boot. By the way, have you -- or anyone else -- had an opportunity of contrasting it with an ARC Ref 3?
Giudocorona, I hope your friend enjoys his Flora as much as I have since I put it into my system. Did he order it with the Mondorf cap upgrade? It really improves the performance along with replacing the stock tubes.

I have heard the ARC Ref3 in two different systems in store settings, never a home audition, so I can't really make a fair comparision between the two.
Wanted to share my experience regarding replacing in the Flora the two NOS Sylvana 65N7GTA's with a pair of NOS Tung Sol blackglass oval plates. Before I get into the sonic details regarding this tube rolling exorcise, I want to thank Baranyi, also known as Bob the "Golden eared one" for sharing his excitement regarding the performance of this type of tube in his system, which motivated me to audition them in my system.

The Tung Sol's are amazing tubes in the following ways:

1) The greatest image density I have ever heard in my system and maybe in any system I have ever listened.

2) The tubes provide the best 3-D image without making individual players sound like "cutouts" that don't mesh with the rest of the soundstage.

3) Unlike, when I tried a set of NOS Mullards in my DAC that gave me just the most beautiful liquidity and warmth, but kinda put me to sleep because they lacked microdynamics and were so "lush" that things like cymbals lost their sheen and sparkle, the Tung Sols provide just spectacular liquidity and easyness, yet still offer punch and dynamics at the same time.

4) The Tung Sols in the Flora offer the most realistic Timbres I might have ever had in my system.

5) The tubes were not only as transparent as the Crome Domes, but I believe they let you hear more microdynamics and details.

So, I think it's pretty apparent that these tubes are keepers in the Flora and brings my system to another level of enjoyment.
Thank you for your kind words. I am happy that you also found these tubes amazing in your system. As you know, I was quite surprised how well they performed in my Supratek Chenin. They completely transformed my listening expectations with the same qualities that you described in your post above. I must say that others on the Supratek thread had mentioned these fine tubes as their reference. I was shocked at how much better they performed than the well regarded Sylvania 6sn7 as well as the Ken rads. I can't wait to hear your system with these tubes. Unfortunately, I will have to wait until next week. Bob

Hi Teajay I had sent you a email did you get it. I was looking into getting the Flora and while doing so found out there have been some changes which I thought you and others would like to know.

The Mondorf caps have been changed to supposedly a better cap choice and the RCA connectors upgraded also.
Thanks Dev, for the heads up regarding these two new upgrades, I'll check into with Tosh. E-mails are very hard for me to get to, so I don't know if its just setting there or not, but thanks for the effort to get this information to me.
Dev, I just got off the phone with Divergent Technologies, the importer of the Flora, and they are not aware of any new caps or improved RCA's that are different then the Mondorf cap upgrade or replacing RCA's with XLR's.

So, what specificly were you informed off regarding these changes and are these provided by Tosh and Divergent or an aftermarket company? Please share the details, thanks in advance.
Teajay no one mentioned to me it was a secret oops! I hope I have not caused any issues now. I'll email you personally again with the info.
Wow! Secret? I received Flora last week and Tosh didn't mention any other caps upgrade except Mundorf. Anyway I'll check it with him again.
Hi Vuckovic, congrats on your new Flora. I would be interested in what your experience has been regarding its performance in the context of your system. Also, have you tried any NOS tubes vs. the stock tubes yet in your Flora?

I still have not found out anything regarding different caps then the Mondorf upgrade, but if I do I will post on this thread.
Hi Teajay,
Thanks for your kind words. Your approach and taste for Hi-fi is very similar to mine so I followed your advice regarding DACs and I bought AA Dac1-Mk4 last summer. After auditioning more than 10 DACs in my system I am very happy with AA. I liked very much Kimber Isomike system which I heard several times at audio shows and I almost bought EMM DCC2 DAC. Comparing EMM with AA there is a clear winner - Accustic Arts. AA has the same amount of details as EMM but AA beats EMM in musicality,and presenting much more wider and deeper soundstage in my system. Way to go Teajay!
Why I bought Flora? I have always been missing a touch/magic of tubes. But I could never "swallow" veil effect of tubes - my first priority in audio is transparency. So after reading your review of Flora I ordered Promitheus TVC - just to try how TVC is going to sound in my system. I liked it - Promitheus is one of great bargains in audio! Flora should be TVC with touch/magic of tubes so I order it. It is still in process of breaking-in so my comments must be taken with grain of salt. Flora with stock Chinese tubes sounded not very good in my system - everything seems smeared, with harsh highs and big soft and bloated bass. Unlistenable in my system after 7 days of breaking-in. In meantime I did a big research about 6SN7 tubes. There is a lot of information about these tubes on web - one of the best links is It is great article about this tube. So the best of the best 6SN7 tubes are:
1. Tung-Sol GT black glass ( one pair was just sold on E-bay for more than $600 - I do not understand this - you can buy the NOS matched pair for much less from dealers with warranty)
2. Sylvania 6SN7W
3. Sylvania 6SN7 GT '52 "Bad boys"
After consultation with some audiophile friends who are very familiar with these tubes I decided to buy "Bad boys". How does now Flora sound after 2 days of breaking in with "Bad Boys"? I can only say that my Sound Lab U-1s never sounded better. I will give more details in few weeks when caps in Flora finally break-in.
About new "secret" caps in Flora - unofficially I heard it is going to be Deulund Danish caps. Are they good? I do not know - my Mundorf are still breaking-in and I do not have a wish to try them in near future.
Thank you Teajay for your reviews and recommendation of one of the exceptional audio products. I would never try Antique Sound Lab product by myself so my hat down to you and your sofisticated audio taste.
I too have a Flora with the cap upgrade and mine has only about 50 or so hours on it. I have already replaced the tubes with a pair of Tung-Sol (not the black glass but the chrome tops). My question to you is how long did your break-in process take and also my system is sounding a bit thin since I put the Flora into the mix and was wondering if that will improve.

Thanks for your info and help.
Hi Donnwags, hope you are enjoying the Flora in your system. To answer your question, it took about 200 hours for the Mondorf caps to really burn in and for the Flora to completely come "on line" and really sing.

I don't know what Tung-Sol chrome tops sound like. Are they NOS tubes or new versions of the original tubes? I'm somewhat surprized that you are experiencing a "thinness" in the overall sonic signature in your system with the Flora, even before mine fully burnt in, it offered wonderful weight and body and just got smoother with more liquidity as the hours went by. I would also be interested, if you would share, what the rest of your system has in it, so I would have a context regarding what the Flora sounds like in your system. Finally, I tried a couple different power cords on the Flora and found that my Harmonic Studio Master gave the most improvement, so are you using the stock cord? If not what PC are you using.
I am using a TG-Audio HSi power cord right now. I have found this to be a good cord for amps and preamps alike. Do you believe that the NOS Tung-Sol tubes could be the issue? What did the orig tubes sound like? I think I might try them and take a listen for as it stands right now I have close to 100 hours on the preamp and it still sounds thin and the music has very little density to it (compared to my other preamp an AR SP-16). Thanks for the help. Are you using the Sylvanias? What differences did they make?
Donnwags, yes my hunch is that that the lack of density or body you are experiencing, unless there is some other malfunction in the Flora which I don't think is very likely, is the tubes you are using.

The original tubes were pretty crappy, lack of details, lack of extension, lack of liquidity, ect., my first replacement were NOS Sylvania 6SN7 WGTA 1958 Chrome Domes, that sounded terrific and I thought that was the end of my tube rolling. Well, then my friend Bob was raving about what happened in his system with NOS Tung Sol blackglass oval plates in his preamp. In the Flora these tubes are just magical, everything got much better, for details go back up to my report on this thread regarding the sonic details, my whole system took a step towards the illusion of real music.

Could it be that the type of NOS Tung Sol that you are using are very different sonicly then the blackglass oval plates, or maybe they are not at full strength?

So, I don't doubt your experience at all Donnwags, I'm just surprized that it's happening in your system. The NOS Sylvania Chrome Domes are an easy tube to purchase and are relatively inexpensive, around $200.00. The NOS Tung Sol blackglass oval plates are getting very rare, I was luckly enough to get another matched pair for backups, but both my pairs were expensive at $450.00 per set.

So, I hope this helps, good luck trying some other tubes, if it does not work out and you decide not to keep the Flora send me an E-mail because I have a couple of friends who would be interested if you would want to sell it.
I did not like sound of Flora in the beginning so I changed stock tubes to "Bad boys". Things improved a lot but Flora really start to sing after 250 hours of burn-in. It was bigger improvement in my system than changing tubes. I guess that Mundorf caps need more than 200 hours to show real potential - in my case it took almost 2 weeks (7/24) of breaking-in. If after this time Flora sounds thin, I guess, something is wrong with the tubes or unit. My Flora never sounded thin, not even with stock tubes. It is superb pre-amp. Give it more time, you will like it.
Thanks for the advice. I will hang in there for at least 300 hours before I decide to change anything. Sounds like it could be the NOS Tung-Sol tubes. I will keep my eye out for some Bad Boys.

Has anyone heard the difference between the stock preamp and one with the cap mod? If so, what was the greatest difference that the mod delivered? Bob
Thanks to Teejay I am now a proud owner of ASL Flora. It sounds every bit like its been described in the review. I'm using NOS Sylvania chrome domes but will upgrade the stock power cord and capacitors. I have one question though, my unit looks exactly like the one reviewd in, but its ASL FLORA EX not EX DT.does anyone know the difference betwenn the 2 (if any)?
Congrats A ahlan, on your new Flora. I hope you get as much pleasure out of yours as I do having mine in my system.

To answer your question I do not believe there is any difference between a Flora marked EX or EX DT. If you have not had the caps upgraded to the Mundorfs A ahlan, you have yet to hear what this preamp can really sound like, so I strongly suggest when you can do the cap upgrade and let us know what you think.
It's been forever since anyone added to this, but here's my $0.02. I have had mine for months now and have played with isolation and with different 6sn7's.
My previous preamp was a Viva Linea with the optional 300B power supply, using Sophia 300b's. I never thought I would be able to do better, but I got flooded and needed the scratch, so it got sold to a very happy European.
As to the Flora, here it is - TAKE OFF THE TOP!!! This preamp needs to be exposed to really open up - pun intended. The best 6SN7's I have found are a pair of Nanjing 6N8P no longer in production. This is after Sylvanias, EH's, VT231's, and even the vaunted Russky 1578's with the holes. I did my research, and then tried the Chinese tubes on a whim, due to the fact that they have metal bases and were for sale cheap. Holy Valve, Batman! they were like the Russian "Holy Grail" 6H8C's but with a cleaner lower midrange, making them very clear, dynamic, spacious, musical, and tonally accurate. I despair to think of these tubes ever wearing out - I will never find another pair.
This preamp also loves to float in air, either on springs, like the mattress springs being passed off as specially designed devices, or on the Spike-Will Magnetic isolators.
If you have this preamp, you owe it to yourself to at least take the top off, and if you don't have anything to float it on, try a pillow, just for fun. Then call me crazy if you want to.