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View Full Version : Firebottle phono stage, Croft 25 and the pitfalls of equipment evaluation



rubber duck
22-10-2014, 15:42
First of all, apologies to Alan for how long this “review” has taken. Second, apologies for using this to flag a wider issue related to the review process. Finally, apologies to everyone for the length of this piece. I have been struggling to write about the Firebottle phonostage for some time now but something didn’t feel quite right, despite having had a long enough loan to form more than a passing impression. It wasn’t just about writer’s block but also a nagging sense of unease that the review process wasn’t quite right. I’m now glad I held off writing that original “review” and am in a better position to now share my experiences.

After all that I’ll get straight to the point. The Firebottle is a very good phono stage, and at the current price, may well be one of hi-fi’s best kept secrets. It sounds sweet and open, detailed and fluid, yet very focussed and precise. It is possibly a touch lean and clean, and light tonally (even with the Shure M97xE, my current preferred cartridge) but still able to capture and convey differences in the timbre of musical instruments and recordings. So a piano sounds like a piano and different pianos sound different. Not only are instruments and the recording acoustic properly reproduced, but perhaps more importantly, the integration and delivery of individual sounds into what we hear as music is sweet and unforced, but without the trade-off which sometimes occurs; the Firebottle comes across as precise, defined and quick, aided I suspect by a lightness and an ultimate lack of authority and heft.

When the Firebottle arrived, I briefly inserted it into my (revolving) system which then comprised the Croft Micro 25 pre with Series 7 power amp, in part to be able to compare it with the 25’s built-in phono stage. I was aware this set-up would favour the Croft in terms of synergy not to mention the additional pair of interconnects required for the Firebottle. Still, the Firebottle sounded good from the onset, with both phono stages sharing a very similar tonal balance and presentation. From my discussions with Glenn Croft, I was aware that Croft preamps do not like being run from the “line out” into power amps with passive volume pots, so I avoided that route. To facilitate comparisons, the bulk of my listening was with my Unison Research S2K, a single-ended integrated amp running one 6550 valve per channel.

While the Micro 25 sounded good enough into the Unison, the Firebottle was better. The Croft was arguably more earthy and rhythmic, more rock’n’roll if you like, but the Firebottle was cleaner, more precise, better defined and as a result, more articulate, particularly in the lower frequencies, allowing you to more easily follow bass lines or complex drumming during dense rock or jazz passages. The Firebottle was more incisive yet refined and delicate compared to the Micro 25’s rounder and broader brush strokes.

All this was quite surprising and disappointing. Surprising because I wasn’t expecting the Firebottle to compare with my Croft 25 Basic (which wasn’t used) let alone the Micro 25. Disappointing because I consider myself a loyal Croft user (yes, I wanted the Croft to sound better) and could hardly justify buying another (a fifth) phono stage. After I posted the Firebottle to the next lucky AoS member, I rotated my system again (as one does) and listened to a Cambridge Audio 640P into a Muse T-amp just for the hell of it. Then I thought why not try the Micro 25 from its “line out”. I had almost forgotten that this could not work and was clearly reminded why: the CA640P destroyed the Micro 25. The Croft sounded sucked out, thin and anaemic with no flesh to the music.

Obviously it should be clear as day to most people hearing this that something is seriously wrong – not with the Croft but with system interaction, and specifically, an impedance mismatch. Simply put, the “line out” on the Croft pre has too high an output impedance especially on phono to work properly into a passive pot. These were Glenn’s exact words to me which was why I sent my 25 Basic to him to modify a year ago. Needless to say, I hastily packed my Micro 25, emailed Glenn, and sent the pre off to him for the same operation. But this got me thinking … was it possible that the Micro 25 could have been compromised when used as a phono stage with the Unison integrated amp? A quick email to Glenn confirmed this: ‘The 25 phono stage would have been compromised’. (I should clarify that Glenn has no knowledge of what I was up to and I had not been in touch with him for a year.)

So despite my best efforts to conduct a rigorous evaluation of the Firebottle, an important comparison with the Croft was fundamentally flawed. Had I posted my initial findings of the Firebottle (in part based on comparisons with the Croft) this would have been misleading, not to mention a great disservice to Croft. I guess in the context of a forum, I could have easily posted an update of my impressions, which I hope to once my Micro 25 returns from Glenn. But this nonetheless highlights the pitfalls of inserting one component for another into an existing system, and then passing quick judgement, what more when little thought or care is taken to level the playing field. While this is harmless enough in a sea of opinion on forums, it is sloppy and even dishonest when it comes to proper magazine reviews. (Sorry, been meaning to get that one off my chest.)

So, the verdict on the merits of the Firebottle in relation to the Micro 25 needs to be put on hold until a rematch can be arranged. But that comparison was only part of this “review” as I don’t consider comparisons between Product A and Product B sufficient indication of what either product is really like. My main findings of the Firebottle on its own remain unchanged. It is a very good phono stage and one which I sorely missed and seriously tried to justify buying. Thanks to Alan for this opportunity and for his patience. I have no doubt he is a very talented (and modest) designer and look forward to hearing his other products.

Haselsh1
22-10-2014, 17:19
I did at one point have the early blue Firebottle phono stage on loan but the results were seriously not good. The basic sound was overwhelmingly loud and shouty and incredibly forward with no trace of delicacy or finesse. I simply had to send it back and look elsewhere it was that bad. At the time, I was comparing it to a Musical Fidelity VLPS, a Heed Questar and a Graham Slee Gram Amp 2 SE.

DSJR
22-10-2014, 17:52
My old Croft 4PP loses bass if listened to via the tape record output sockets. Glenn has offered a mod to update it. Having done one or two things myself (under Glenn's direction I should add), the line stage has much improved and is now highly transparent to the source and the phono stage is excellent. I believe this may be one of the reasons why Stereophile magazine got their measurement knickers in a twist (perhaps) when they tested the integrated, as the only output they could have used I think, was the fixed output one (tape out?).

One thing I did when this mattered, was to upgrade an MF X-10D line buffer and use that in between tape out and the recording input. Very little insertion loss and a MUCH better sound when recording ;)

Gordon Steadman
22-10-2014, 18:11
I did at one point have the early blue Firebottle phono stage on loan but the results were seriously not good. The basic sound was overwhelmingly loud and shouty and incredibly forward with no trace of delicacy or finesse. I simply had to send it back and look elsewhere it was that bad. At the time, I was comparing it to a Musical Fidelity VLPS, a Heed Questar and a Graham Slee Gram Amp 2 SE.

I believe I have that very machine. What you describe bears zero relationship to how it sounds in my system.

Ali Tait
22-10-2014, 18:18
Alan built me a two boxed balanced version. It's superb, and a big step up from the single box IMHO.

Firebottle
22-10-2014, 18:26
Well firstly I would like to say thank you to rubber duck for sharing his impressions of the Firebottle loan phono amp.

No apologies needed for any perceived delay in posting.

Secondly the early blue Firebottle phono stage that Haselsh1 and others trialled was seriously flawed. This was corrected in the circuitry of the current loan unit.
Further improvements have been made in the present Firebottle Plus phono stage, including increased output drive into low input impedances, which leads nicely into the point made by rubber duck about equipment matching.

With equipment such as the Croft phono stages without some form of buffer on the output, the sound is always going to be compromised if connected to an amplifier with a low input impedance, hence Glenn's comments. A point to be noted when making equipment comparisons.

:cool: Alan

Firebottle
22-10-2014, 18:29
I believe I have that very machine. What you describe bears zero relationship to how it sounds in my system.

You do Gordon but it has been extensively re-worked up to current specification :thumbsup:

:cool: Alan

Andrei
22-10-2014, 20:05
A good write up Jeff - in content and language.

struth
22-10-2014, 20:40
I have a slightly modified version on the new firebottle + and I find it top notch and very versatile. Blew the Whest out of the water.

twotone
23-10-2014, 06:59
I've just received an updated Firebottle plus from Alan, I had a Firebottle MK1, the first one in fact I believe, which I bought second hand earlier on in the year from Spur7 (Paul) and I had that amp hooked up to a Rega Brio-R and was delighted with it but I subsequently bought an new (SH) amp, an XTZ Class-A100D3 integrated, and totally messed up the sound from my vinyl front end.

The result was that FB mk1 and the XTZ amp didn't gel with each other and the sound from vinyl replay was a bit 'meh', I had lost the 'sparkle' and stopped listening to records.

I got in touch with Alan and he suggested upgrading the FB MK1 to a Plus with MM/MC and an upgrade to the plus circuitry down to an impedance mismatch between the two amps so, as I had sold off the Brio-R, I decided to go ahead with the upgrade (nothing ventured and all that) and boy am I glad I did!

Vinly replay is even better now, much better in fact, piano is superb and drums and bass are just bleeding fantastic but I've only had the phono stage for a few days so don't want to jump into a review too quickly but so far I am absolutely delighted.

Component mismatching is very easy to achieve but very difficult to sort, I was about to sell the XTZ and buy another Brio-R in order to try to get things back the way the were but now I think I have the best sounding system I've ever had and it's much more flexible with having the ability to now use MC carts easily.

The only thing I'm going to do now is change my speakers from Jr149s to a pair of Harbeth P3 ERS's and then I'll be done except for a new cart when required.

Tony

Elephantears
23-10-2014, 09:32
I think Jeff's comments on the difficulties of comparative reviewing are very wise, and there must be 100,000 forum posts out there that are flawed for not heeding his caution about the intricacies of system context.

That said, I heard the Firebottle that Jeff had on loan and thought it was superb. I'm very impressed with what Alan has done here. I hear it slightly differently to Jeff, in that I found it very tonally full rather than lean, although it is a question of both semantics and perspective here. Jeff is right that there is a cleanness to the sound, and I suppose he is focusing on the space and clarity that creates. I heard the way that sounds are very clearly sculpted, and I heard excellent fidelity to the tonal body of instruments; of saxophones in particular (I always tend to focus on saxophones).

For example, I recently bought the Analogue Productions mono pressing of 'Blue Train', but I was a little underwhelmed when I listened to it either through my Diablo/NCPSU, or my Croft Micro 25 (but I was using this through the line out, so we can't make a faithful comparison here). The Firebottle put the saxophone forward in the mix, and gave it this very compelling body that I wasn't getting on the Diablo. It was the first time I'd really enjoyed this pressing.

Now to be faithful to Jeff's thoughts on context, I should say that I was using a Nagaoka MP500, and the first thing I heard when I installed this cart recently is how it puts the central voice of a recording quite forward, but gives it a really satisfying body. I heard that quality with the Diablo, but I felt the Firebottle really did it justice. What I can't really say is how much my comparative values are the result of a particular synergy. Actually the Nagaoka sounds really good with the Diablo, but perhaps the Diablo really shines the most with a dynamic MC cart that shares its values, whereas the Firebottle and the MP500 share the same tendencies and support each other.

On the other hand, I have read a comment on the Firebottle thread from a Nagaoka user who felt that whilst the match was good it might be too much of a good thing (presumably meaning that the sound became too rich, warm, or forward?). I can't see that happening, but it's worth remembering that some systems need a complementary strategy from source through the chain, whereas some systems benefit from a yin/yang approach, where different components offer different values (e.g. a very clean and dynamic MC cartridge through a system with very rich and full bodied valve amps).

However important it is to question the reviewing process, the clear message is that this is a truly engaging phono stage that has a good balance of virtues. I'm looking for a valve stage myself, and I'd really like to hear the new version in my system.