Tisbury Audio Mini Passive Pre-amp

[RichB]

Hi Rich,

Yup, that sounds like a plan

Don't get me wrong here though, the Tissy is NOT replacing the Croft. It was bought for a bit of fun, a) because I'd never heard a passive in my current system, and b) to reduce the 'heat count' in the system during the hot summer months.

I'm happy to report that in that respect it's been a great success, and also sounds superb (much better than I thought it would - offering amazing value for money), but I'm not going to be abandoning the Croft anytime soon!

Marco.

Ha, I didn't think so... I know how you like to warm your tootsies by some glowing valves lol.

[rubber duck]

Not sure if it's called a 'mini', but it's the older model with the plain wood fascia (no writing on it), point-to-point wiring (instead of PCBs), and no gain controls, etc, underneath. Nothing to interfere with the signal path. Just plain and simple!

Both versions have the same model name. As for the whole hard wired vs PCB debate, I don't think it's that straight forward.

This from Tisbury: 'The circuit board is superior to point-to-point. It’s the same components, still copper wired, and it’s in a better and more controlled layout.'

Even Tron has this to say: 'When hard wiring is not the best method for assembly a circuit board is created and special attention is paid to each track to ensure we maximise the way the complex audio signal passes across the board.'

That said it would certainly be interesting to compare the old and new versions.

[Marco]

Hi Jeff,

Yup, I get all that, and it *may* be true (I can't comment because I haven't done the comparison), but it's contrary to my current experience, dictating that hard-wiring (done well) is better than any PCB, which to my ears, to varying degrees, always seems to impose its own distinctive 'sonic signature' on the music signal.

Hey, I guess unless someone does a back to back comparison, we'll never know. Also, in my system, I don't need the gain switches included on the new model, which are just something else to get in the way and sit on the signal path.

Marco.

[Macca]

I have one with a DACT Stepper I can bring too.

I could also bring my LDR passive pre along. Mega-passive bake-off!

[Ali Tait]

If we get time.. :-)

[User211]

Lol - well, that certainly isn't my experience! I've had a DACT stepped attenuator fitted to my Croft for about four years now. The amp is used for many hours every day, and I've had no problems whatsoever with contacts wearing out. It sounds stunningly good and significantly outperforms any pot I've used so far

Marco.

I said longevity. Even an ALPS Blue Velvet will last that long... might be on the verge of getting noisy as they do. And they really do.

They also work in discrete steps which is a bit of an arse with some low on step counts. Can never get the right volume.

P&G me any day...

[Ali Tait]

Not that keen on the DACT in my passive. It uses metal film SMD resistors, sound a bit harsh to me.

[Marco]

I said longevity. Even an ALPS Blue Velvet will last that long... might be on the verge of getting noisy as they do. And they really do.

Nope, no noise here whatsoever, not do I expect any to develop. If you want proper longevity, then Anthony TD has been using them in his Soulmate preamps since 2004 (with zero issues in terms of noise or contacts wearing out, reported by him or any of his customers who've bought a Soulmate): http://www.tubedistinctions.co.uk/soul_mate.htm

I expect the DACT unit in my Croft to function in the same way, and for a similar amount of time.

They also work in discrete steps which is a bit of an arse with some low on step counts. Can never get the right volume.

Point taken, Justin, but I have no such issues in my system, nor indeed does Anthony in his. It would be impossible to live with the DACT for so long otherwise. Incidentally, the Croft preamp (with DACT fitted) was part of the AoS system you heard, and raved about, at Scalford.

I guess it depends on how the preamp works that it's fitted to, and also what the electrical relationship is with the partnering power amp - oh and how sensitive (or otherwise) are the speakers. As ever, it's all about synergy

Marco.

[Marco]

Not that keen on the DACT in my passive. It uses metal film SMD resistors, sound a bit harsh to me.

Sure, as with anything else, it just depends on the circuit the DACT is used in. They are rather 'honest', however, and thus act (IME) simply as an open window, letting one hear exactly what the circuit they are connected to is doing. Therefore, if it sounds harsh, it's most likely a mismatch with the partnering circuit and/or other system components.

I seriously doubt anyone who's heard the Croft would say that it sounds harsh, as it's an extremely natural and musical sounding device. I'll bring it to the next NEBO and you can have a listen for yourself. It would be an interesting active preamplifier reference point to use against the assembled passives

Marco.

[Marco]

Interesting info from Wes, contained in the FAQ section of his ebay advert:

What type of attenuators do you use?

Our SMD stepped attenuators use a 'series' configuration, similar to the excellent DACT and Goldpoint attenuators. These have a track of resistors connected in series and the volume is varied by moving the output up and down the track. This mimics a standard potentiometer and is ideal for audio. They typically have long life, low operation noise, extremely high sound quality, and fairly consistent impedance throughout their range.

Obviously, he rates (as I do) the DACT units - and for good reason.

I've not used Goldpoint, so can't comment on those. However, I can categorically say that the Tisbury (with its SMD stepped attenuator) offers the same, if not even greater, transparency as the Croft does, fitted with a DACT stepper. Both have that 'wide-open window onto the music' thing going on, but combined with a relaxed and effortless musicality, which I love and indeed demand from any components used in my system.

I can pay it no higher compliment. It really is a remarkable little device, and I'm utterly delighted with it!

There are also no gain or impedance issues in my system, with the Tisbury, certainly on line-level, as both the RPi and Sony DAC provide the required 2V output, and my TD Copper amp has good input sensitivity and plenty of gain.

I've long suspected that (probably for sound electrical reasons), passives, in general, work better with valve power amps than with many SS amps, unless the latter have been designed specifically to be used with a passive device, which I believe is the case, for example, with NVA equipment.

I realise, however, it's not quite as simple as that, and that other factors come into play, but I feel it's no coincidence that the best sounds I've heard to date from passive devices have been when used in conjunction with high-output [at least 2V] audio sources, connected using short (0.5m) ultra-low capacitance interconnects, suitably compatible valve power amps and high-efficiency speakers, as I'm doing now.

Tomorrow I'll use the Croft purely as a phono stage, and connect it thus to the Tisbury, where I suspect the high output levels generated by my vintage SPU-G/T cartridge (with its built-in SUTs, providing tons of gain) will form a superb partnership with it. More on that later

Marco.