Discontinued moving coil transformers & head amplifiers

Discontinued moving coil transformers & head amplifiers

Older models of MC transformers are ...erm ... old MC transformers ...how can I put this, there has not been a great change in the quality of transformers over the last 60 years or more, there has been a gradual move towards better materials and a slight improvement in design and winding techniques but nothing similar to the series of revolutions that we have seen with electronics in general, so basically the only difference between a new MC transformer and an old model may be down to the effects of ageing and the fact that modern MC pickups generally have slightly different characteristics than they generally had a few decades back, thus mating an old transformer with a new pickup or the other way around may not result in a perfect match but close enough in most cases, and unlike electronics the effects of aging in transformers are not always on the minus side.

All transformers and wound transducers suffer from magnetic build-up and other gradual changes that affect the characteristics of the units with the passage of time, mind you the effect is not always negative and for electric transformers it's nothing that will have a great effect on the performance but on audio transformers the effect will be noticeable over decades, this can often be rectified by rewinding or demagnetisation. Some manufacturers like for instance Ortofon will rewind old transformers for you and there are also independent workshops that will perform this work, make sure to find a workshop that has specialist knowledge of audio trannies, I have sent an audio transformer to a general transformer workshop and got back an unusable unit.

Still if it's only a is 10 or 25 years old unit you should not bother and if it is a transformer wound from silver wire the chances are that it will actually have improved with age, but be aware that some of the transformers on the market are 40 years old or more, we have actually seen Thordarson trannies from the 1920's advertised on Ebay as "almost new, little used", so do a little bit of research before acting.

Apart from this the only change that have been seen for the last 40 years or so is the change from fixed impedance models to variable impedance models, most of the old fixed impedance models were sold as single transformers housed in a simple metal cans that hi-fi stores, radio outfitters and mixer manufacturers etc. then integrated into mixing decks, turntable bases or amplifiers and so on as either pick-up or microphone amplifier stages. Most modern transformers are generally pairs fitted into separate boxes however and a large portion of them offer variable impedance, it should be noted though that there is quite a difference between the sound of transformers, especially between a high quality one and a low quality item were you can hear the difference quite easily but it is often not as pronounced as between head amps or other pieces of active electronics.

As for head amplifiers you are well advised to stay away from anything much older than 15 - 25 years old or so, the advancements in op-amp technology have been so great that listening to a 25 year old model and a modern one side by side is a revealing experience, and makes you wonder why you never noticed all that noise before.


Made 2 MC head amplifiers that were primarily intended to mate with the Accuphase pickups, the C-7 was originally introduced in Feb. 1979 or a few months before the introduction of the original Accuphase AC-1 pickup, it is a strangely elongated nondescript black box very much unlike what you would expect from the company and is based around op-amps and thus sounds a bit dated, it has a fixed gain and impedance at 26 dB and 100 Ohms respectively.

It was replaced in Oct. 1984 with the more upmarket C-17 model that was produced until the company stopped the manufacture of its entire phonographic line-up in 1989. Unlike the C7 the C17 actually offered some variability in gain and impedance and could thus be used with pickups that had different specifications to the models Accuphase itself was offering, it was also considered to be an excellent sounding unit in its day but was in turn considerably more expensive than the C7 model. Note that both units have switchable power supplies and can be used anywhere in the world.

Unlike the C-7 the signal path in the C-17 is almost entirely discrete and therefore is a considerably more refined sounding than its predecessor and in fact one of the few headamps from the 80´s that has stood the test of time, the Dual Mono design helps as well. However it should be taken into account that the second hand prices for the unit are also considerably higher than for the C-7, in 2011/12 they were routinely going for USD 1000 in the USA and in some cases even more in Asia and Europe.

Resources: Accuphase C-17 Product brochure in PDF format -- Accuphase C-7 brochure in PDF format

The Accuphase C-7 technical specifications are; Frecuency responce: 5Hz ~ 100kHz. @ +0/-0.2dB. Inputs: 2x cinch + earthing terminal. Max input level: 35mV RMS. Outputs: 2x cinch. Gain: +26dB. Total harmonic distorion: Less than 0.002% at max input/20Hz ~ 20kHz. Signal to noise ratio: Better than 72dB @ 0.1mV input, A-weighted. Bypass: Yes. Size:10.2 x 6.1 x 35cm (Width x height x depth). Weight: 2.5 kg. Power requirements: 100, 117, 220 and 240V (Switchable). Power consumption: 5 watts.

The Accuphase C-17 technical specifications are; Frecuency responce: 20Hz ~ 20kHz. @ +0/-0.2dB. or 2Hz ~ 100kHz. @ +0/-3dB. Inputs: 2x cinch + earthing terminal. Max input level: 150mV @ 1kHz/+26dB and 76mV @ 1kHz/+32dB. Rated input level: 0.1mV @ +26dB or 0.05mV @ +32dB. Input impedance: 10, 30 or 100 ohms (Switchable) ohms. Outputs: 2x cinch. Output levels: 2mV. Output impedance: 50 ohms. Minimum load impedance: 10k ohms. Gain: 0dB, +26dB or 32dB (Switchable). Total harmonic distorion: Less than 0.005% at max output/20Hz ~ 20kHz. Signal to noise ratio: Better than 72dB @ +26dB gain or +66dB @ +32dB gain. Bypass: Yes. Size:19.4 x 14.2 x 37.1cm (Width x height x depth). Weight: 8.1 kg. Power requirements: 100, 117, 220 and 240V (Switchable). Power consumption: 30 watts. RRP: 190,000 ¥ in 1984.

Audio Innovations
Made the Series 1000 step up transformer in the 90's, has a toggle for high/low impedance.

Made the HA10 head amp in the 80's, it came without a power supply (12v, I think some of their amps had such an output) and sounds slightly noisy compared to modern units.

Made the MK2L step up transformer in the 80's, has a great reputation in the USA for it's warm sound but it sounds a bit dated compared to some modern European and Japanese alternatives, this model is popularly know as the L type but there was also a P type that we have not been able to find any info on.

Made the AU-310 transformer, it's a unusually small standalone model.

Introduced the PE-1 electronic MC amplifiers in the mid 80's and it was manufactured up until 2000 when it was replaced by the current PHA-100 model. Critically acclaimed in it's day but it should be noted that it's a bit noisier than the current model.

Electro Sonic Laboratories (ESL)
Shipped mono transformers (encapsulated in rather sexy bakelite) for their mono MC broadcast carts in the early 50's, mostly historical curiosities by now.

Fidelity Research
Had a range of step up transformers one of the nicer ones was the FRT-5 that unusually enough sported 3 inputs that could each have a different setting thus enabling you to have 3 different carts connected to your amp. Another model is the XF-1 it has an input impedance of 4 to 18 Ohms and gain is 30db so the unit is thus only useable with medium impedance carts such as the ones from Fidelity Research itself. This was considered to be a quite good units in it's day (early to mid 80's). The company also had at the least one model of a battery powered head amp that seems to bear no name but the specs are : Gain 24dB, Impedance 100-ohm, output impedance 47k-ohm, Frequency Response 20-20,000Hz. This model seems to have been designed specifically for use with FR pickups since the gain and impedance are not selectable.

Made the battery powered LN-1 MC pre-preamplifier, it had a switchable gain of 26 or 32 db and 2 input channels.

FM Acoustics
Made the FM 212 Reference head amp that was considered to be the bees knees a few years back, has a input impedance switchable between 12, 50 and 100 ohm's, meant to be driven from a 9v source off a FM preamplifier, the company no longer makes the power supply that was meant to go with this amp but one of their newer models may work, or any 9v capable audiophile grade supply come to that.

Made the MC-T100 step up transformer. Specs : Gain: 1:10 (20dB). Optimum input impedance: 30 Ohms (20 > 40 Ohms). Optimum load impedance: 47k Ohms > 100k Ohms. Distortion: 0.0035% at 1kHz, 200mV output. Separation: 97dB at 1kHz..

Mark Levinson
Made the battery driven JC-1AC head amplifier in the 70's, you can find more info on it here, despite the praise it's given on that page it should be noted that it's way outdated and it's original designer has even come out recently to say he would not use it under any circumstance.

Made the T24 in the early 80's, a keenly priced low ratio model.

Made an electronic head amplifier in the 80's designed to mate with their MC pickups, it's not suitable for all MC's though, more info here.


The predecessor to the current high end T-3000 model was the T-30, we believe it was introduced in 1982 or 3 and was in production well into the 90's. It featured switchable impedance from 3 to 48 ohms. Size is 4x8x14,2 cm. Another sought after model is the T-5, these are tiny units with male phonoplugs on one end and a female on the other that are best put on the end of your cable and directly into the phono stage/amp, this unit will work with impedances from 3 to 40ohms. Some owners of Ortofon SPU carts absolutely swear by the old JS series of transformers that the company sold in the 60's and seventies (it was made by another Danish company Jørgen Schou), they were considered very good in their day but it should also be noted that you can send the to the factory for and update and a rewind (according to reports this is really a worthwhile thing to do), note that they will of course work with any other pickup that matches the SPU impedance characteristics but that the unit most often seen on the second hand market is the 0,32M type and that unit has a low ratio of 1:10, fine for SPU's and sensitive inputs but not enough for many others pickups and not enough for many phono inputs. Ortofon also had other models on the market in the 60's and 70's such as the stereo T-6600, the MCA-76 and the budget STM-72 but I have preciously little info on them, the T-20 how ever is very similar to the current MKII 2 model but features slightly inferior specs.

Had the HA-T10 transformers, this is exactly the same unit as the Ortofon T-5 listed here above.

Thorens - Restek
Made the MCA-5 tranny (in the 90's I believe), impedance is switchable between 30, 200 and 1000 Ohm's.

Uesugi Brothers (U*Bros)
Has made quite a few models including the high end 5-L from ca the early 80, much sought after in Japan and comes in at some 15kg.

Next Page : Discontinued RIAA Preamps -- Previous Page : Moving coil preamplifiers

© 1993 - 2013 Ólafur Gunnlaugsson, all rights reserved.

The site was last compiled on Sun Nov 10 2013 at 9:15:00am