Still quite impressed with the layout of that phono pre-amp as I already mentioned, had a quick play with it in LTspice, and got a perfect RIAA EQ. Does need high Hfe trannies to do that though hence BC459 or of that ilk.
What it actually sounds like is something else of course
Many many years ago I remember trying to make something very similar, but must have made a balls-up somewhere or the drawing I was copying from had a mistake in it, 'cause what I got was an oscillator not an amplifier! In hindsight maybe the feedback network was connected to the wrong place.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
O that's interesting I kinda of though with its age it would be a bog standard unit it does sound fairly good thou but masked a bit by the preamp wonder if it's worth a rebuild with its own PSU the Caps in the single path are Tantalum Caps thou and the feedback cap being such a small value maybe a problem to get these days
Oh really, do you know some folks think tantalum caps sound horrible, so could be worth replacing all the elecs with nicer modern ones, like e.g. Panasonic (RS range), also, they'd be much smaller physically than what was used back then. So will replace the tantalums easy I think. Might sort out the noise problem as well if there's a noisy cap, they are quite old now not sure how long they are supposed to last.
If it isn't that then maybe look into replacing resistors with something of better quality ~ you could end up with just the board as the only original bit left! lol
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
Yep I read that somewhere too so have never used the tantalum Cap ether the plan will be to recap the whole Amp at some point Valve stuff to do first thou at least the transistors are sorted out thanks for you help there mike
Well I Have Just Acquired a second Pioneer SA-6200 well in January I will so thinking I will bi-amp the system using the NAD pre-Amp as I am at the moment with the SA-2600 or maybe a Nelson Pass BI Buffer
So which way to bi- Amp the normal way one amp driving Left/Right bass with the other amp driving the Left/Right top end Or Use The Mono Button And mono Block The Amps placing by the Speaker With sort speaker leads and longer interconnections which way would you think best
I always think long interconnects are just inviting trouble. Low signal and shielding problems.
Better to have long speaker cables. IMHO.
Long interconnects can cause problems, that's one reason why I went for Pre3 with it's output transformers, and also the reason behind my cathode follower pre experiment.
The only thing necessary for the triumph of evil is for good men to do nothing.
I always think long interconnects are just inviting trouble. Low signal and shielding problems.
Better to have long speaker cables. IMHO.
Hi al
Interesting I am running my Sky HD Box with a 5 meter length of 75 ohm down lead into the NAD pre amp with no problems I think it sounds better than using a sort lead
I always think long interconnects are just inviting trouble. Low signal and shielding problems.
Better to have long speaker cables. IMHO.
Long interconnects can cause problems, that's one reason why I went for Pre3 with it's output transformers, and also the reason behind my cathode follower pre experiment.
My cathode follower pre happily drives 5 meter cables to the TV/Cable box and it sounds great as a sort of stereo AV option without all the bells and whistles. I'm dead happy with it
When you say long cables can cause problems can you give more detail into what problems you experience we know most cables will sound different due to their resistance /Capacitance? Of there different lengths and also pre amp input/output t impedances etc
Spookily, I also am currently using a 5 metre stereo screened lead to feed the power amp, moreover, it's running parallel to a bunch of mains leads (various uses). But provided the source end is low impedance no problem. Unplug that end and I get a bit of hum obviously. At the mo the source is mostly the Ambit FM tuner or Akai recorder, ocasionally CD player, all of which have op-amp type output drivers. Even the Trough Line is OK with it's 50k output pot.
It probably helps having the "master" vol control on the power amp as well.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
colin.hepburn wrote:When you say long cables can cause problems can you give more detail into what problems you experience we know most cables will sound different due to their resistance /Capacitance? Of there different lengths and also pre amp input/output t impedances etc
I was originally going to make a "nice quality" pair of leads but couldn't be asked in the short term (might still do later), so at the mo it's just a ready-made 'brand X' twin lead from Rapid. 'Black' side is 1.25nF, 'red' side is 1.42nF. You'd never know it though. Which is pretty good for 5 metres actually, I've seen >1nF with just a 1.3 metre lead. I was expecting just a tiniest bit of treble attenuation but there isn't, even with the Trough Line tuner.
Biggest problem with it is the plugs are a bit naff.
You need to bear in mind though a screened lead can act like a transmission line, so the source needs a 1k resistor in series to kill any returning reflections caused by high speed pulses or transients.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
Well as I use the CT100 Coaxial for most of my interconnections in one metre lengths except for the five metres of WF125 on the Sky HD Box
I am not sure of the Sky Box Output But I Guess maybe a standard 2 volts out which is running into the NADs pre Input sensitivity and impedance 770 mV / 20k ohms / 470 pF
WF125 Coaxial Spec
Nom DC resistance ‡/Km inner (outer) conductor 15(9)
Nominal characteristic impedance (Ohms) 75
Nominal capacitance (pF/m) 53.5 see other CT100 here http://www.satcure.co.uk/tech/cablespecs.htm
All these cables sound well balanced as well as sounding smooth and detailed this includes the Five Metre of WF125 on the sky Box
