trying a dl103

Love it or hate it, it just won't stop
User avatar
Nick
Site Admin
Posts: 15709
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#16

Post by Nick »

I think Andrew and Nick first brought this idea up a year or so ago.
Credit goes to Andrew on this one,
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
Andrew
Eternally single
Posts: 4206
Joined: Thu May 24, 2007 2:18 pm

#17

Post by Andrew »

And originally elsewhere....before me...

-- Andrew
richardcooper2k
Old Hand
Posts: 780
Joined: Thu Jun 07, 2007 2:32 pm
Location: sheffield

#18

Post by richardcooper2k »

ok, so i didn't do what i said. instead i soldered 470r across the input to the phono stage and tried it with out the step ups. the sound seemed a lot 'fuller' than with out the resistors. to see how much difference it had made i unsoldered the earth ends of the resistors and couldn't tell any difference this time !

i'll try it with the step ups but first i'm going to try the above again just to make sure i can't hear the difference again. prehaps its me ?
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#19

Post by IslandPink »

The pace issue could easily be dependant on having enough mass loading on the headshell for the 103 to develop bass properly ( since it is very low compliance ) . Timing and dynamics are often linked to low bass performance. This is easier said than done if you're running it on the Vic air arm, since you'll end up grounding the 'slider' if you add to much mass .
You could experiment between 150R and 1000R for loading on the 103 , I think I had about 200R last time I used one. I use about 100R on the 103R .

Mark
"Once you find out ... the Circumstances ; then you can go out"
richardcooper2k
Old Hand
Posts: 780
Joined: Thu Jun 07, 2007 2:32 pm
Location: sheffield

#20

Post by richardcooper2k »

i've never had a moving coil cart before so i didn't know what difference in sound to expect by changing the loading from 47k to 470r. but i did expect to notice something, even if it wasn't a change in prat
i should have more time tomorrow to try adding the step ups and adding some mass. i think the arm should manage a 20p coin as others have suggested.
could be a case of cloth ears. but i did notice a big difference going from the pickering to the denon
richardcooper2k
Old Hand
Posts: 780
Joined: Thu Jun 07, 2007 2:32 pm
Location: sheffield

#21

Post by richardcooper2k »

tryed adding one of the cinemags. 1:9, no loading resistors. now i can tell quite a big difference. with the step ups i get a fuller sound, more bass slam and treble detail. so i've got my prat back but with some hum. tryed moving the white step up ground wire to different points but it didn't seem to make much difference

i think its a big improvement. have to see what a little time to live with it brings.

got a bit too much gain though. thought about doing the shunt pot mod and using a bigger resistor

any thoughts ?
Gerry
User
Posts: 72
Joined: Mon Jun 25, 2007 10:57 pm

#22

Post by Gerry »

Richard

There are 2 ways of hooking up the CineMags. The older way used to cause hum. CineMag have now changed the wiring diagram.
Have you got the older diagram? Check their website.

1:9 should be perfect for the 103. I use the 1:18 for my 103R. I do have the shunt mod with a 100k pot.

Regards
Gerry
richardcooper2k
Old Hand
Posts: 780
Joined: Thu Jun 07, 2007 2:32 pm
Location: sheffield

#23

Post by richardcooper2k »

do you use 91k on the shunt mod ? i thought if i used more i could restore some sensitivity to my vol pot

i'm not sure wether i can find separate signal and power supply grounds on my phono. white is to chassis earth also quite a long wire

i havn't shortened the step up wires, is this likely to make a much of a difference ?
Gerry
User
Posts: 72
Joined: Mon Jun 25, 2007 10:57 pm

#24

Post by Gerry »

Richard

I can't remember exactly what I've got on the shunt mod but is somewhere in the region of 80-90k

I haven't shorted the step wires either, so not sure if it'll make a difference.

Regards
Gerry
Will
Old Hand
Posts: 497
Joined: Mon Jun 11, 2007 10:35 pm
Location: Northumberland

#25

Post by Will »

Richard

Keep the ouput wire (purple) short as possible
for min. hum.
richardcooper2k
Old Hand
Posts: 780
Joined: Thu Jun 07, 2007 2:32 pm
Location: sheffield

#26

Post by richardcooper2k »

more listening. due to the increase in detail some recordings are now a bit in your face (prehaps just bad ones. other sound awesome (compared to the sound i had before.

i don't have an earth lift resistor on my pre which has the step ups in it rather than in a separate box at the moment. wonder if that would reduce hum. always had some hum from the phono stage but don't notice any from the line stage with a line level source

running out of time now as i'm off to the south of france rock climbing tommorrow and get back just in time for owfest. so i may have to bring it with hum
richardcooper2k
Old Hand
Posts: 780
Joined: Thu Jun 07, 2007 2:32 pm
Location: sheffield

#27

Post by richardcooper2k »

ok so i've changed a few things, had a listen between each one, but it seems to take me a while to decide about/notice differences so i'm not quite sure what sound difference is atributable to which change.....

as everyone else noticed apart from me at owston i hadn't got the arm set up right :oops: . this has been corrected

connected screen from cinemags to power supply earth rather than signal earth - this has definatley reduced hum

connected 680r across input of 1:9 step ups

sound has become crisper (some records which previously sounded a bit woolly have come to life). a bit thin and dry on some recordings (maybe its just after hearing the lcrs, simons and toppsys at owston)(imagine a lush 70s sound and then imagine the opposite, but not harsh)(timing seems good but could be more fruity i feel)(cymbals sound great but seem a bit forward in the mix)(arm already sloping down to pivot)

all in all, better on most records
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#28

Post by IslandPink »

'A bit thin and dry' was how I found loading the cart on the primary side ...
:?

MJ
"Once you find out ... the Circumstances ; then you can go out"
richardcooper2k
Old Hand
Posts: 780
Joined: Thu Jun 07, 2007 2:32 pm
Location: sheffield

#29

Post by richardcooper2k »

oh dear. maybe i should try load some on each side of the step ups. or could i use a cap in series with the resistor so i short out less low freq. any suggestions on the value ?
Richard Higgins
User
Posts: 159
Joined: Thu Oct 18, 2007 12:54 pm
Location: Oxford

#30

Post by Richard Higgins »

Hi Richard
I'm using a 103 and cinemags.
I use the 36 tappings directly onto the 47k resistor.
This article refers; http://www.theanalogdept.com/sut.htm

The main bit of interest is;
“Now lets look at an example of matching an MC phono cartridge with an appropriate MC step up transformer. The cartridge is the Denon DL-103. Its output voltage is rated at .3mV. We will partner this with a Cinemag CMQEE-3440A step-up transformer. The one in the illustration. This transformer has a split primary coil that offers 2 possible turns-ratio settings. For our DL-103 we can choose the 1:35.4 turns ratio. When we do we end up with a resistive load of 37.5 ohms. Here's the math: 47Kohms / 37.5^2= 37.5ohms. This seems very near to a match between the resistive load of the system and the internal impedance of the Denon. All should be peachy....right? Well, lets slow down a little and take a look at the output voltage with this cartridge and transformer combination. Output voltage times turns ratio equals voltage seen at the MM input. .3 * 35.4 = 10.6mV Seems rather high doesn't it? It may seem like we will be overloading the MM input with this system but in actuality we won't. Here's why: When the resistive load is equal to the internal impedance of the cartridge, the cartridge output voltage is reduced by 1/2.**”

I tried various loadings and ended up prefering this.
I'd be interested to know what you think.

Regards Richard H
Post Reply