Quality Audio Preamplifiers – the INA217 and NE5534
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Imagine paying U$5 000.00 for a stereo pre-amplifier? Ever notice how the more exotic brand names carry a hefty price tag?
The INA217 is sterile – rightly so!
The one thing that amazes me in the audio wars and also based on forum topics is why we have a jaundiced eye on sterile sounding pre-amplifiers. If I were to purchase a power amplifier I would ensure that there are no changes made to the input signal except amplitude. The pre-amplifier which is essentially a voltage amplifying device needs to be able to boost and cut frequencies as well as replicate the input signal at a higher amplitude with minimal noise introduction. The perfect preamplifier would therefore be a typical microphone preamplifier with inserts to add FX and frequency equalisation. Adding RIAA equalisation to the front end for vinyl reproduction would be a must have as well. Would Texas Instruments have brought out the INA217 for any other purpose? Exactly, yet I believe through the numerous articles on the web that certain of the audiophile community find the sterility of this instrumentation op-amp just plain ‘boring’. Personal opinion is also divided when it comes to great audio equipment such as the likes of the NAD 3020. Many believe it to sound like a tube amplifier. The 3020 series had 2N3055/2N2955 bipolars in the final stage. These, compared to modern audio output devices just lack a piece of everything but yet the 3020 is known to be one of vintage audio’s greats, putting good sounding equipment at the reach of the budget audio spectrum. I had the 3020 preamplifier which was sold as the 1020 – it even had the open space ‘through holes’ for power amplification on the board. The downside, (excuse the pun, intended) was that the RCA sockets used to work loose – poor design but it wasn’t designed for ‘disco’ work. Read as in “mobile”. The point I am making here is that the NAD 3020 was all about the pre-amplifier, methinks, and compared to modern equipment I doubt this pre-amplifier would really stand out yet, indeed, the quality was superb for it’s price tag. I also believe this pre-amplifier came into existence because the ‘audio-phile’ community in those days were using the 3020 to jump start bigger output stages than the 3055/2955 combination. Yes, there are better preamplifiers out there but they cost a darned sight more than this unit. (this pre-amplifier cost about $175 in 1984). Pre-amplifiers have come a long way since then in terms of SNR and dare I say it, bandwidth.
Minimalistic Audio at premium prices
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Essentially the biggest jump we have had in terms of performance of consumer and pro-audio goods has been the handling of digital data. This comes with a hefty price tag as well of course, good DACs cost an arm and a leg. Do we really need to handle digital data – yes, if we want surround sound. Many audio buffs only use stereoscopic imaging which then does not rely on a DAC for the reproduction of audio from a turntable. Some of the best systems I have heard is vinyl, to pre-amp, to power amp to loudspeakers. For this minimalistic setup users pay premium prices – frankly I am in awe of anyone shelling out 10 000 dollars for such a system but if this is your hobby and passion then so be it.
Why the INA217
Whilst we have avid collectors of audio equipment clambering over themselves to get the ultimate system, emphasis always remains in the small signal amplifiers, power amplifier power supply and loudspeakers used. Good quality, nay, exceptional quality power amplifiers can be built at very cheap cost except for the power supply and cooling. Audio monitors and pre-amplifiers not. The ISA110 from Focusrite is an incredible piece of equipment yet it uses the humble NE5534. I have an entry level powered mixer which uses the NE5534 as the staple diet chip. Everywhere. For it’s price point many musos and engineers believe it to be one of the best. Audio-philes swap them out for lower noise chips when and where possible. The INA217 is a better performer, yet pundits believe the 5534 sounds better. For the price point yes but the specification tell us another story. (they are not interchangeable by the way). Go to the AudioMasterClass website to read the story about the 5 dollar preamplifier which outperforms a 1500 dollar boutique pre-amplifier. There is a lot that goes unsaid but the truth is, embarrassingly enough, blind listening tests proved that the basic, raw bones INA217 was the better performer. Pundits are unhappy about this however as their argument is that the listener hears what they want to hear. Right, of course yes – that is why it was a blind test. You heard what you wanted to hear and the cheapest pre-amplifier came out best. Such is the way of modern audio equipment – price is not always the deciding factor. What is important here is that the INA217 is a fantastic IC, designed as an instrumentation amplifier it lends itself perfectly for accurate audio reproduction. Of course the $5 test also was a huge promotion for this chip.
The 5534 and Why do we add noise to the signal path?
The NE5534, likewise is a great chip but yet is not recognised as top class. Strange, because the ISA110 proves it is. To move on to another strange phenomena, the tube/IC hybrid. The low noise chip pre-amplifier is proven to be a winner in many aspects on the audio front but manufacturers design equipment with a tube pre-amp, usually the 12AU7 or 12AX7 (ECC82/83) in the voltage amplification stages as well, often used to over-drive the signal to get classical tube sound. What’s more, the tubes run at very low voltages, often only at the phantom supply rail of +48V (used for powering the condenser mic pre-amp). You may think this defeats the object but this pre-amplification technique is very popular amongst musicians which can and does sound very good depending on where it is used, usually for instruments. Moving on to FX inserts on a microphone/line pre-amplifier, this is also used quite often to reproduce classical tube sounds, varying through all the well known tube amplifier brands. BOSS is one famous manufacturer producing stomp boxes, usually in line with the instrument. Now here is a thought, producing effect units for home use or consumer products. The biggest problem one faces when purchasing an integrated amplifier for surround or even stereo use is the lack of quality effects. Even amongst the best of them when selecting Hall 1, Hall 2, Music, Movie etc sounds very cheesy. In fact I wish they would rather just add in a decent tone control for each channel. More so, buy a separate effects block for between pre- and output stages. The reason why I harp on about this is because if you want to listen to music then why change what the sound engineer spent months trying to get right. Over compression is a typical example of a poor recording etiquette but there is enough on that subject from way better qualified persons than myself on the internet. Why buy an amplifier which needs to have ‘music’ effects added. Bizarre, to say the least!
So the problem here is that you have a great pre-amplifier, a great power amplifier and we go and mess up all the hard work by adding more noise to the circuit. In many cases this is done deliberately, if one knows the whys and hows but in the hands of a consumer wanting the best out of his system it makes no sense whatsoever. Just as we do not put cheap speakers on to a high end amplification system or vice versa we should not interfere with the signal path. That’s my honest opinion.
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The INA217 makes things happen
To sum up, paying $5 000.00 for a stereo pre-amplifier in my mind is ludicrous. A quality rack mountable chassis will set you back 100 dollars at most. It’s not the box that counts but what happens inside. Sometimes fewer components is just that much better. The INA217 makes this happen. Being a bad boy I prefer to put all the electronics inside the box which includes the power supply. If the scope don’t see it, I don’t hear it.
Stockists:
- Texas Instruments
- Mouser
- FiveFish – Kit (uses THAT and Burr-Brown)
- RS Components
- Mantech Electronics (South Africa)
There are obviously other companies out there selling this product. Be cautious of where you buy from. The companies listed are well-reputed. Who knows, maybe TI will give you a free sample. They are just that kind of company.
[Ed: This TI chip is a direct replacement for the SSM2017. It is RoHS compliant. Costs vary globally. THAT produces the 1510, a drop in equivalent. I am in the process of prototyping an INA217 MC preamp but time is a problem otherwise I would have published photos of the finished product. It will be used to feed a mixer. Results so far are very encouraging. Input from VinylEngine. Note the bias current problem).
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