After an informative discussion on here, I ended up replacing it with a DL-301 (which could be justified as a 'like-for-like' replacement for the no-longer-availavble DL-160 in an accidental damage claim).
I used this opportunity to get the TT serviced and when it came back I thought it sounded great, with a really smooth musical quality and really meaty low-end. Tracking seems brilliant, with minimal IDG but potentially lacking a little 'air' at the top-end....(although I understand the Denon's can take a while to break in). That top-end thing was really playing on my mind... the DL-301 is low output, and there are myriad horror stories online about impedance loading etc which got my paranoia racing.
So, I thought I'd try a little experiment to see if the frequency response really was accurate, and whether I needed to worry about it (my Phono1 doesn't allow the loading to be changed, for reasons that Richard could explain better than me). I should thank the guys at Billy Vee in Lewisham for kindly letting me borrow their demo Rega Aria Phono stage for a couple of hours to help experiment with this.
As I have very little confidence in my auditory memory, I tried to facilitate a more immediate comparison by recording a short section of a number of tracks out the back of the phono stage into a little Zoom R16 digital recorder. I then normalised the files (to -1db) for more exact comparison - assuming identical Dynamic Range the files should be identical volume. The same cables were used for each, although I had to put the Phono1 through my P20 to attenuate it a little (otherwise it was peaking on the R16) so there was an additional cable in there for that.
Having started this arduous (and arguably pointless) process, I then expanded the 'experiment' to include files taken from my old Project Debut III and, as a control my Raspberry Pi / DAC+. I even took some samples using the Phono stage on a really cheap and Folio Notepad mixer (which arguably produced the most interesting results of all). I ran the files through the TT Dynamic Range Meter to help quantify some of the audible differences. Finally, I wrote a little web-player to allow the files to be compared directly and the 'volume' matched, to account for those dynamic range differences.
I'm not sure if anybody is interested (or has even read this far) but you can find this here:
https://d3udekiaqq01eg.cloudfront.net/outer.html
Wait for the word 'Loading...' to change to 'Play' and then click to begin playing. You can select the source to listen to by clicking in the column labelled 'Active' (yellow box will move down). There is separate volume for each file.
There are 4 tracks 'on offer'. I tried to choose tracks which were dynamically very different, and actually the different equipment did produce different results on each. The files themselves are in sync, but as yet I've not been able to get the HTML5 web player to keep them completely in sync when switching. I think this works best in Chrome browser, at least on my Mac.. Obviously all files have lost something by going through the relatively cheap A2D in the Zoom, so it's more of a relative comparison.
Some (possibly) interesting and unexpected findings:
- It seemed impossible to find a digital version which matched the DR of the vinyl, even with albums (Dutch Uncles - Out Of Touch In The Wild, Brutal Truth - Need to Control remaster) which I'm pretty certain would not have a completely separate vinyl master. I understand from online research that there might be technical reasons vinyl appears to have a wider dynamic range for the same source, but I might experiment further with some records I know to have the same master as the CD.
- The really cheap Folio Notepad phono stage not only reduced top-end detail and blurred the low end (probably expected) but also applied a significant reduction in Dynamic Range.
- My old Project Debut III / OM10 arguably has a little more top end than the Thorens / SME / DL-301, but perhaps a less musical midrange.