The Classic CROFT Vitale SC Preamplifier - Upgraded

The Croft Acoustics Vitale SC is a classic preamplifier. Discover how the upgrades by Firebottle Audio have brought this sleeping beauty bang up to date.

In early 2023, I decided that I'd put together a more robust balanced system, and with a new balanced amplifier on the cards coming into Tannoyista, the time was right to get a nice preamplifier sorted too.

I've always loved Croft gear. And the man himself, Glenn Croft, was always a pleasure to work with. He always had time for questions, unless there was a major cricket match being broadcast, of course.

My previous experience with Croft preamplifiers took things to a new level, and even Glenn was quite happy to say that the upgrades he performed on my Epoch Elite were more than enough.

The problem for me at this stage was that Glenn never created anything with a balanced circuit; he could have I suppose but he didn't have to as the demand wasn't enough to even think about it, which was totally understandable. However, I wanted to integrate Croft for the use in a balanced system.

There's not much I can say about the sound of Croft gear in general that's not already known, it's all over the net and for the majority of owners over the years, they've been very happy. So it's unfortunate that some never really gave his preamps a proper go due to the controversial twin-volume pots.

When I first bought a Croft Basic back in 2010 and later a 25R, I didn't think I'd get on with dual controls but once I had it in my system, I didn't mind them. After a couple of months, I generally have them set in or around a certain position anyway, so it was only a matter of fine-tuning, which worked out fine. 

But, it tended to be more time-consuming to set up I suppose, and could've been the reason why some didn't get on with them. This was a shame because the sound from individually channelled pots did sound great.

With my Epoch modifications, I decided to go with a (the then new) Khozmo attenuator, and because there was no room to accommodate two mono pots alongside the other upgrades, Glenn begrudgingly fitted the stereo version. But, he did admit to me that it sounded just as good.

Exploring the Croft Vitale SC

The preamp for this balanced modification was a Vitale SC dating from around 2002/03. The chassis used on this model was probably the strongest Croft ever used. Even the later Charisma and Epoch didn't have a chassis as heavy and as sturdy as this.

As Glenn had not long passed away, I wanted someone who had a wealth of experience with valve gear. I needed someone who would maintain the respect and integrity of Glenn's work.

The job landed with the very same person who had the Vitale for sale at the time, Alan at Firebottle Audio. Based in the Midlands, UK, Alan's creations over the years have always been held in much respect, and he's a total wizard at upgrades and repairs.

After a week or so of planning, and a further few weeks of work, the end result was ready and pretty mind-blowing. After my other Croft Epoch Elite was upgraded to use 6SN7s, I just had to have that sound' with the Vitale. For me, the larger octal valves give a much more solid presentation. 

So my request was to have a fully balanced 6SN7 output stage while still using the smaller signal valves originally designed by Glenn. The unbalanced section still worked as it was originally intended, which was great as well.

Upgrade details for the Vitale SC

Here's more detail from Firebottle Audio regarding the details of the upgrade.

This was an interesting project, a bit of a challenge but then I like a challenge.

Originally the phono gain was on the high side compared to most phono stages, but that is a characteristic of the valve and circuit choice that Glenn made. The gain was excessive for the systems gain staging so in order to reduce it I had to do some modifications.

Reducing the gain of a valve stage can only really be done by incorporating some feedback, be it with cathode degeneration or full negative feedback from output to input. Feedback wasn’t an option for the phono section due to the inevitable alteration to the phono equalisation, it being a passive EQ design. The originally fitted 2x ECC83 are high gain valves so I decided to replace one with a lower gain valve.

This threw up a little problem. Glenn’s design used one valve for both first and second gain stages of each channel. I had to rewire the first ECC83 to provide the first gain stage for both left and right channels. The second valve was chosen as the 5751, this gave the necessary reduction in gain to suit the full system gain. I also made a minor change to the phono EQ.

The rest of the modification was to include a fully balanced option as requested, using 6SN7 valves. Fortunately, the case had plenty of room to incorporate this. The EIZZ 4-section volume control is the key component to enable a balanced function. An additional mains transformer and filtering choke were fitted to power the 6SN7 valve stages.

The 6SN7’s were wired as buffers after the new volume control to provide a low output impedance, one polarity also wired to the original RCA output sockets to provide an unbalanced output. An additional input selector switch was fitted to accommodate the two new balanced inputs as well as the existing unbalanced functions. This is also a 4-way switch, so in order to provide greater flexibility the Line 2 (CD) input was also wired directly to this switch. Wiring all the new silver wiring to this switch was quite tricky, but as said I do like a challenge.

The positions on this new selector switch are Unbalanced Inputs (phono and line inputs), CD direct, Balanced input 2, Balanced input 1.

The last modification was to change the heater supply to the 6SN7’s from AC to DC which lowers noise even further. It also provides a certain amount of acceptance of vagaries in the cathode/heater characteristic between valve samples. Modern film capacitors have also been added for decoupling in the power supply.

With two balanced inputs and one balanced output, I was a very happy bunny.

The components used in the upgrade:

The volume control used this time was a true balanced unit from EIZZ. This was the first time I've used the EIZZ and the feel is solid and it has a nice torque. Just like the Khozmo but softer and less clicky/snappy in its stepped attenuator-like action. 

I've often found that the sound from using film resistor pots can vail the sound somewhat. But surprisingly, the sound of this pot is excellent with lots of detail and depth. Although, one drawback was that it has 24 steps which was something I would have to get used to as the Khozmo had 48 steps, but hey.

For the input selectors, I chose the British-made Blore Edwards OPXR selectors. Now, these were really excellent. Like the EIZZ, the torque is just right and the connection is extremely solid.

The supply of the heater supply to the larger Octal valves was changed to DC rather than AC which brings down the noise levels.

The Vitale now uses:

x1 ECC83
x1 5751
x1 ECC81
3x 6SN7

The Sound

With all of the upgrades in place, the sound from this preamplifier is solid. There's something about the sound of Croft gear which can really bring you to the forefront of the music. And to get to that stage, and with anything vintage, things do need to have someone who knows what they're doing to sympathetically tweak the basis of the sound to then add the extras.

The sound has just the right amount of detail and texture. Alluring you in with swathes of un-stifled ease really gets you, the build-ups and impact really impress and yet looking at this preamplifier, with its subdued and conservative looks, it makes you see the elegance of it.

No matter what you throw at it, from fast-paced music like Rock, Dance, and Trance, to delicate music such as Soul and classical. The Croft spills the beans of the music and its makeup. Snapping instances of vivid drama into the air in front of you. This is what Croft brings, and in this instance, the Firebottle Audio upgrades have very much exceeded my expectations.

Conclusion

The Croft/Firebottle Vitale is something of a wonder. And to think that there are quite a few of these still out there in the world, if you're thinking of changing it, please think again. This preamp is a giant killer; it just needs some work. But in this case, I'd only trust Alan of Firebottle.

And lastly. A tribute to Glenn. Glenn was a great guy to deal with. Unfortunately, I never met him but I had plenty of calls with him and he was always on the ball with any of my requests. He wouldn't take your money if he felt you wouldn't hear a difference, a true and honest gent.

He will be missed immensely in the Hi-Fi world and so this goes out to him and his family.

R.I.P Glenn Croft

Contact Firebottle Audio

Alan Kendall at Firebottle Audio
paramotorpilot64@gmail.com