Headamps - Grass Greener?

[Bigman80]

I'd just like to clarify that the Jfet input that Oliver is referring to is a special linearised Jfet circuit that doesn't resemble a traditional head amp.

YES!!!!!!! Doesn't sound like any head amp I've heard. I can't say it doesn't have an effect because everything does, the difference is, I don't know if or what it is because it's so transparent. It's been a very much deliberated decision to go with it and I'm very glad that I did.

Best bit is, it's Integrated into the PCB circuit so no RCA connections No cables No interference. Just purity.

[Jimbo]

Sounds like a perfect solution to what could have been a complex problem.

Nice one Oli. Look forward to hearing it although I may have heard something similar in a Firebottle amp ?

[Bigman80]

Sounds like a perfect solution to what could have been a complex problem.

Nice one Oli. Look forward to hearing it although I may have heard something similar in a Firebottle amp ?

No Jim,. The JFET circuit can't be implemented in a Headamp. I asked Alan if we could do that so I could see the results before committing the Wizard to surgery. Unfortunately it just isn't possible so it was all in or nothing. The surgery was a huge success and I'm very grateful to Al for allowing his intellectual property to be fitted.

I am looking forward to your comments on it mate. We will sort a day out soon

[Marco]

I've seen quite a few times on various forums that people have bought old transformers to use as a SUT. Often they're transformers from mic preamps. The trouble is, those transformers are often only OK - they will work and you will get a usable signal, but they're less than ideal. This post on this very forum is an example:
http://theartofsound.net/forum/showt...em-Help-needed
The typical source impedance of a dynamic mic is about 200 ohms, whereas the typical source impedance of a LOMC cartridge is more like 10 ohms, so transformers designed for microphones tend to have a lot more windings and higher winding resistances and are generally less than ideal for use with a LOMC cartridge. They will work, but usually with less than fantastic performance. And of course, such transformers will colour the sound and appear to have a certain "character", but the reality is that they're just not optimised for the job they're doing.

All good, and very valid points, Andrew, so thanks for highlighting them. Little in audio is entirely straightforward

However, despite that, it is still possible to find some excellent vintage transformers, which can be used very effectively in an audio context, such as those from Jörgen Schou I once bought on ebay, for use with my (then) SPU cartridge. Here's the original thread on AoS, showing some pics:

http://theartofsound.net/forum/showt...or-Ortofon-SPU

Trust me, those were truly superb sonically, and in a way that I've NEVER heard from anything else since!

There was nothing overtly coloured about their sound at all [after all every audio component ever made is coloured to some degree] - just breathtakingly vivid sonics, brimful of sparkling detail and with a gloriously lucid and textured midrange, making vocals and instrumental detail sound uncannily lifelike.

Unfortunately, as I lived with the JS traffos for a while, and listened to them with various different recordings, I discovered that they weren't the best electrical match for the cartridge I was using at the time (had too much gain), so I had to sell them on.

However, aside from that, the sound I heard left an indelible impression on me, and ever since then I've vowed to find some more, this time to suit some of my Denons, and so that will be my intention in due course, and once done, hardwire them into the circuit of my Croft preamp.

No head amp I've heard so far, no matter how good (or 'accurate'), has gotten close to the music magic that those little babies produced!

Marco.

[Marco]

Agree up to a point with most of this Marco .. though while there are challenges from positioning and cables I don't see that it's a **must** that SUTs have to be in the same box as the phono stage. The best SUT I've ever heard was the external Audio Note S9, staggeringly, gobsmackingly, sell-a-kidney intoxicatingly good (and so it should be at some stupid retail price like £20k or something).

Sure, but for me it's a must if you want to hear the full potential of the transformers concerned. How much better, one wonders, would they have sounded if they had been hardwired into the circuit of the test preamp? 'Good' is great, but 'best' is always better!

I've had very good results with several head amps including the Slee Elevator and the Denon HA-500 and HA1000, so I'm far from dismissing head amps as an approach. Where ground loops and hum are an issue, they can be a magic bullet that takes the pain away. But I remain convinced that a good SUT is still the way to go if you want the optimum possible out of a low output moving coil.

Me too, hence my last post. However, the fundamental fact is that both head amps and SUTs sound different (do things different, musically) and like anything else, have their respective talents. That's why I'd like to have access to good examples of both, and a variety of suitable cartridges to use with them, so I can enjoy their respective 'takes' on my favourite music

Marco.

[Marco]

Those transformers have an enormous turns ratio of 1:120. For a cartridge with an output of 0.3mV (I'm assuming that's what your cartridge had) that seems like an insanely high ratio. I'd be very interested to measure them but I don't suppose I'll ever get the chance. However, I have measured a SUT with a 1:100 turns ratio. I can't remember the name of it but it wasn't cheap. Its performance with a 10 ohm source (pretty typical of many LOMCs) was diabolical. May have been OK with something like an Audio Note cartridge, but rubbish with something like a modern Audio Technica.
I found similar results with an expensive Audio Note transformer - an extremely high turns ratio with terrible performance when used with a 10 ohm source. Again, probably ok with one of their extremely low output cartridges or an old Ortofon with a similarly low source impedance and output voltage, but rubbish with a typical modern LOMC cartridge. I'm talking about being 3dB down at 12kHz!

Can't argue with that, but as someone who primarily likes using the best vintage cartridges (and in general dislikes how modern LOMCs are 'voiced'), said transformers are a valid option - and they can sound stunning.

As I've said many times before, in the final analysis, I don't give a toss how something measures. How it sounds to my earholes, in my system (with my music) is ultimately what matters most!

Marco.

[Marco]

Absolutely, and the big difference is, you build stuff for a living, so you need to use measurements!

I don't - I'm just a music lover with (these days) largely a passing interest in hi-fi.

Marco.

[montesquieu]

Those transformers have an enormous turns ratio of 1:120. For a cartridge with an output of 0.3mV (I'm assuming that's what your cartridge had) that seems like an insanely high ratio. I'd be very interested to measure them but I don't suppose I'll ever get the chance. However, I have measured a SUT with a 1:100 turns ratio. I can't remember the name of it but it wasn't cheap. Its performance with a 10 ohm source (pretty typical of many LOMCs) was diabolical. May have been OK with something like an Audio Note cartridge, but rubbish with something like a modern Audio Technica.
I found similar results with an expensive Audio Note transformer - an extremely high turns ratio with terrible performance when used with a 10 ohm source. Again, probably ok with one of their extremely low output cartridges or an old Ortofon with a similarly low source impedance and output voltage, but rubbish with a typical modern LOMC cartridge. I'm talking about being 3dB down at 12kHz!

This makes sense to me. The AN-S9 I referred to previously was for use with an AN-Io, which is 1 ohm at the cartridge coils, and I think the turns ratio was something close to the 1:100 you mention (from memory probably 1:90).

For the most part my cartridges tend to be 'old design', low compliance, and low impedance - I've owned an Io (actually two now I think about it), more typically I use SPUs of 2-4 ohm , the latest Ikeda just arrived (see my recent post about it) is 2 ohm, the Miyajima monos 4-6 ohm. The only 'modern' cartridge in these terms that I use is the Miyajima Madake at 16 ohm. Many of these are also low output (the Io is 0.05mV - yes you read that right).

The AN S6c step-up I had had additional lower gain taps on the silver coils for matching with higher impedance designs but you certainly wouldn't want to use the '1 ohm' input for a 'normal' cartridge!

[Firebottle]

Hi Andrew, I can understand your confusion.

"This thread has me quite baffled. By my definition a solid-state circuit between a LOMC cartridge and an MM/RIAA phonostage is a headamp whether it's built into the phonostage or in a separate box."

In reality it is a 'headamp' in that it is an extra gain stage before an MM input. However the implementation actually gives too much gain for it to be classed as a simple headamp.

"No Jim,. The JFET circuit can't be implemented in a Headamp.
I don't see why not, though I don't know the details of the circuit. Perhaps Firebottle could elaborate on that."

The inclusion of the Jfet in the first stage is done in such a manner that it can't be used individually and give the same outstanding performance.
I know this doesn't satisfy your curiosity but it is something unique as far as I am aware.

[Bigman80]

This thread has me quite baffled. By my definition a solid-state circuit between a LOMC cartridge and an MM/RIAA phonostage is a headamp whether it's built into the phonostage or in a separate box.
Some MC phonostages aren't like that, they're really just an MM phonostage with more gain, so they can't be said to have a headamp built in.

Firebottle fitted a headamp into your phonostage, at least by my definition.

You didn't remove the headamp, you just had it built into the phonostage.

I agree.

Yes it is, at least by my definition.

I don't see why not, though I don't know the details of the circuit. Perhaps Firebottle could elaborate on that.

Andrew,

When I said "I removed the Headamp" I was refering to the ones I had on loan here. Same as the SUTs I had either purchased or on loan.

In effect it's a Headamp yes, but without all the emphasis and mechanical signature I heard from the demo units here.

It's really quite simple.

SUTs = Expensive, hard to find synergy, a Unicorn of sorts. A PITA and all the best ones cost the same as a small family car. hard to isolate from hum. Incredibly fussy.

Head amps = Cheaper, less fussy, less magic, sonically impressionable, easy to site.

I wasnt happy with either so went a different route. I'm sure it was mentioned in this thread that a hard wired method to add gain was the best way. I agree.