Published 21 June 2012

Time's up for the Thorn stereo
Morphed into a Denon

A colleague has had an old Thorn FM64A doing sterling duty in the office since the mid-1970's. Thorn had a connection with the EMI group and was making radio equipment in the UK and its subsidiaries in New Zealand from the 1950's. The old stereo was a bit tired, the wood veneers were coming unstuck, the illuminated dial pointer didn't illuminate and the speaker terminals as well as some of the switches were a bit dodgy. For the most part, the Thorn stereo had been working perfectly. Lately however, the amp had acquired a buzz on both channels. It was probably curable by replacing power supply capacitors and a bit of a workover, but since my colleague had wanted some new features anyway, it was time to finally put the old Thorn out to pasture.

Thorn stereo

The design of the Thorn is certainly dated now, but in many ways it was a real technicians stereo. It had features like A & B speakers, with a selector switch to run either speaker set or both in parallel, or none if you wanted headphone listening. These days it will be called something like 'Zone 2'. The FM tuner had a stereo/mono switch plus a switch to turn FM muting on and off, in case you wanted to pick up those really weak stations. There is a tape loop, to accomodate the fashion of the day of recording music from any source and playing back using a tape cassette recorder. The source selector included TWO Aux inputs. There was a high cut filter switch to remove the worst of hiss from weak stations or from tape replay. The usual 'loudness' switch boosted the bass for Fletcher-Munson correction at low levels. Although this method of loudness compensation is crude, it was and still is commonly used. To round off the feature list, there is a 5-channel graphic equaliser and a mic input. Yes folks, Karaoke was around in the 1970's.

One item you never find in modern equipment is an output, on an RCA connector, from the FM demodulator. This provides a buffered version of the received FM composite signal in its entirety, so you could if needed, connect to a 'better' stereo demodulator, or even a dedicated SCA demod. Naturally there is a signal strength meter and a FM tuning meter to ensure you manually centred the FM carrier correctly within the receiver passband. None of this modern synthesized nonsense, which makes it all far too easy...

The Denon AVR-1912

Sorting out a suitable replacement took a while. It had to be a multi-channel AV receiver because the owner wanted to be able to switch HDMI sources as well as a few other features.

We had to find a reasonably priced unit that could:

The Denon AVR-1912 was the best fit we could find.

Denon AVR1912 front

Note the the pictures of this unit on some websites are different to the actual model as supplied. The difference is mainly around the large source selector knob on the left side. Some pictures, including that on Denon's site, show some buttons for Zone 2 and tuner preset instead. Also the disposition of functions along the long strip of buttons is different.

The look of the Denon is rather austere, but this seems to be quite common for the category of product. Regarding specifications, I will simply say this is a 7.1 channel surround processor/AV receiver with seven 90 watt amplifiers. It does not have a built-in amplifier for a subwoofer; instead providing a line output for an active sub. There are plenty of sites out there with specs and reviews. I will refer you to the AVR1912 on the Denon website for the complete data.

Denon AVR1912 rearThe rear of the Denon is shown at right. Not as daunting as some I have seen. The six HDMI inputs and one output are along the top. We have done no performance testing of this unit so I cannot tell you just how well it lives up to the performance hype. I am quite sure though, that performance is exemplary as expected of a top tier manufacturer like Denon and will be indistinguishable in sound quality from any other in the same league. One thing we did check was the standby power consumption. This is commendably low; being around 0.1 watt. The remainder of this review has some comment about the features, the user experience to date and then a few words of comparison with the old Thorn receiver.

Getting her up and running

Getting started is not a 5 minute job. The first thing is of course to connect some speakers. At least the two front/main ones. Then it is recommended to connect a video monitor to the HDMI output. This is because the Denon is far easier to set up and use via the GUI than using the front panel display. Although you can use a composite video monitor, the clarity of menus on screen is far better via HDMI.

Then we connected an FM antenna and proceeded to set up some stations. The auto seek function worked but it loaded a preset with every signal it could find, including weak unlistenable ones. Figuring out how to delete the unwanted ones and sorting the remaining stations into a sensible order took a while. We did have to pore over the downloaded manual. Denon provide a paper 'getting started' manual, but you do need the full version.

To connect HDMI inputs is simple enough but note this Denon has only two composite video inputs plus one component video input. To concentrate on HDMI sources in 2012 is fair enough, but be warned if you want to run many legacy analogue video sources. The Denon does convert analogue video to HDMI and from what I have seen on a 24" pc monitor, it does a reasonable job.

Detailed setting up

Our experience with settings is that it is not simple and you should allow plenty of time. You don't have to set up everything to get running but we have come back to settings several times and suspect we haven't yet found everything. You can assign friendly names to sources and even assign sources to remote buttons. The name on the remote button doesn't change though! The full speaker setup, surround options, speaker distance, height settings and related matters are extensive, including making use of the supplied microphone to preset the equalisation for your room. We tried the Audyssey room calibration feature briefly and it worked fine, although the calibration file was deleted a few days after when we did a firmware upgrade.

One feature which some might like is that the surround-rear amps can be re-assigned to run the main speakers in bi-amplified mode. Of course you cannot get at the 'input' of the amps to insert an electronic crossover, but some of the benefits of bi-amplification will accrue.

Getting the network part running wasn't that hard. The receiver uses DHCP and the router assigned it an IP address. This receiver is 'internet-centric and a lot of the facilities as well as controls are built around internet radio as well as DLNA functions. When it finds it has an internet connection, it heads off to see if there is a firmware upgrade. If there is, it harangues you on screen every time you select a network source. Eventually we succumbed and it went through the process. The upgrade process took about half an hour. You have to leave the Denon to it and go and paint the house or something.

In use

The front panel is sparse. There is a large volume control and source selector. Four broadcast preset radio channel buttons are headed 'Quick Select'. The assignment of these is done in the menu. There are also internet radio select buttons. Behind a small cover is one composite video/stereo input. One thing you can miss for a while is a row of buttons just below the display. These are for a miscellany of functions including display dimmer, radio preset selection, sleep timer, ipod input select and status button. The labels for these are quite hard to read in reduced light. Perhaps they should have been back-lit.

The remote is complex although one gets the hang of it after a while. Each source has a dedicated button, which is something I prefer. However, there is another source select button and a set of quick select buttons which are unnecessary. The Denon is made to be interacted with using the GUI rather than the front panel.

Fundamentally, this model is meant for experienced home-theatre users and not for Granny of Gordonstown, unless she is also in the experienced user category.

What's missing?

There are no line-level outputs apart from the subwoofer feed. That brings me to the main gripe about the Denon and is where the old Thorn receiver wins hands-down. No tape recording loop. There is no way to get line level audio out of this receiver. My colleague did want some line level audio to feed into his pc for analysis. He would have settled for a digital audio output but there is none either. I had a few suggestions but all of these have a disadvantage:

  1. Take the headphone output and use a simple level reducer. Not the best solution since the level depends on the volume control setting and is also dependent on the equaliser/processor settings.
  2. Use the Zone 2 speaker output and use a simple level reducer. This requires configuring the surround-rear speakers to become Zone 2. One could set this to a fixed low volume, but on this model, you cannot have sound from HDMI or digital audio inputs appearing on Zone 2. The output is also dependent on the equaliser/processor settings.
  3. We could buy an external HDMI audio extractor box like the Octava HDDA11V13 and connect in line with the HDMI output. This would work, but of course is a further expense and the Octava provides only stereo.

Comparing the Denon with the Thorn

Well, of course, there is no real comparison. The Denon has seven 90 watt amps; I think the Thorn is 10 watts per channel. The Denon has a remote, HDMI video switching, surround sound of many flavours, networking, internet radio and more. But it's not all one way traffic. The Thorn has a useful tape out loop, it starts instantly, unlike the Denon which takes 7 seconds to boot. The Thorn interfaces with the human more directly, via front panel controls that do exactly as they say and does not require you to power up a visual display unit to see what is going on.



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