Printable View
Thanks, Alan. Well in that case, the Tisbury certainly doesn't sound harsh either.
Like I said, it's all to do with the circuit stuff is put in and how it's implemented overall, not to mention the hi-fi system in which it's used. Therefore, IMO, it's a mistake to form definitive conclusions on any component or piece of audio equipment, when only having heard it in certain contexts :)
Marco.
Well having spent years trying all sorts of components in all sorts of gear, I tend to prefer good carbons to metals. I think that qualifies me in having an opinion!
Of course it does, Ali - I never said it didn't. However, that doesn't invalidate my contrary opinion, based on not inconsiderable experience, having lived with and enjoyed metal film resistor-based steppers for years [and not finding them in any way harsh]! :)
Marco.
I worry that 'classic' carbon film resistors change in value over many years' use, but whether it's time or stress related I really don't know. Glenn Croft has used metal film resistors in his products for decades now (Holco's in my 4PP's I'm told) and harsh is something they've NEVER EVER been. Sweet certainly (although less, now Glenn told me a few updates to make to it), but never harsh.
Making the chain more transparent to the source *can* show tonal hardness in many speakers, the crossovers of which can go wrong right where our ears are the most sensitive IME. Live acoustic 'brass' can pin you to the wall with natural intensity, but this 'hard hitting' tone isn't the same as electronic harshness. Ali, I'm sorry if I'm going totally off the track.
This afternoon, I was shown the (non-ladder) attenuators NVA use. Beautifully made by the supplier and I have to say the 'feel' is superb, as well as the solid mechanical engineering, which is a plane above the Chinese attenuator I bought for one of my Crown preamps (see the Ken Rockwell review of the IC-150 for details). I was given the chance to try one of these, but I need to have a 'proper' passive preamp to use them in - my home made bodge-up just won't do, whatever it 'sounds' like :D
Hi Dave,
Yup, same with my own Croft preamp, which DACT stepped attenuator aside, is full of metal-film resistors. Indeed, I don't think I've ever heard any piece of Croft equipment sound harsh.Quote:
Originally Posted by DSJR
Ali can of course comment for himself, but I think you're spot on, as what you've described above also mirrors my own experience. It's all about 'opening the window', as it were, as widely as possible, and sometimes in doing so, lets in some things that you didn't realise were there before...Quote:
Making the chain more transparent to the source *can* show tonal hardness in many speakers, the crossovers of which can go wrong right where our ears are the most sensitive IME. Live acoustic 'brass' can pin you to the wall with natural intensity, but this 'hard hitting' tone isn't the same as electronic harshness. Ali, I'm sorry if I'm going totally off the track.
That's when you have to decide if what you're hearing that you don't like is what *should* be there [i.e. is part of the music recording] or not - and decisions made at that point can either send you on the right path to reproducing a genuinely faithful representation of the music, or not, thus shaping your system's development accordingly.
Oh, and you can't measure for it either - only experienced ears can decide ;) It certainly helps having a fundamental understanding of how real instruments and voices actually sound.
Marco.
Ok, then I know nothing, am half deaf, have a crap system and not a clue how real instruments sound. Happy now?
No. Why are you reacting like this, daftee? No-one is saying that you're not entitled to your opinion, or that it isn't valid; just that we don't have to agree with it if our experience differs! :D
And more often than not, we agree about most things in hi-fi. No offence intended, but I just think you're wrong to say unequivocally that metal-film resistors = harsh. That's all :)
Marco.
I think there is a bit of leg pulling in that comment Marco, and you bit :eyebrows:
Personally I think it depends exactly where in the circuit certain resistors are used, though with my limited experience I couldn't say definitively.
:)
If so, that's fine - but it didn't seem that way...Quote:
Originally Posted by Firebottle
Yup, I'd agree with that. If you accept that every component used carries its own 'sonic signature', then quite simply, you don't want that signature to dominate. Therefore, as you say, you employ it selectively in certain positions within the circuit, where you consider it best facilitates what you're trying to create.Quote:
Personally I think it depends exactly where in the circuit certain resistors are used, though with my limited experience I couldn't say definitively.
That principle applies to resistors, as much as it does to capacitors, valves, or anything else inside a piece of audio equipment; indeed it is precisely how 'voicing' is achieved. But then, as an equipment designer yourself, you already know all that! :exactly:
Marco.
I remember the Tisbury sounding a tad etched or sharp compared to my Air Tight passive.
The next time I get another passive I'll get the mic out to see if it was real. Be really curious to see what it makes of "potentiometer rolling". If it measures no change I'll be surprised - it easily "sees" valve rolls but that's a rather more complicated device than a potentiometer.
Note, Marco, I am not using the mic to decide what is best. I am using it to see if there is a measurable difference to give credibility to what I think I have heard i.e. check I am not deluding myself. Very important, I think.
Absolutely, and worthwhile doing, as long as in the final analysis you trust what your ears are telling you, not just the measurements! ;)
Again I have to state quite categorically that, in my set up, there is no hint whatsoever of the Tissie sounding 'etched', sharp or harsh - simply very transparent of the signal that it's being fed.
However, I could imagine that due to its brutal honesty, in some set-ups, especially those with a tendency towards forwardness [and where various 'sticking plasters' have been applied to address it], such wide-open transparency may become a bit 'too much of a good thing'.
Marco.
Won't a mic measurement only give you frequncy response? For evidence of harshness wouldn't you need distortion measurents?
I've currently got the Croft hooked up the to the Tissie, with the former acting simply as a phono stage, and as suspected playing vinyl, it sounds superb.
It may not *quite* have the airy and spacious 'out of the box' presentation of the Croft, when also being employed as a preamplifier, but it's easily good enough to listen to downstairs in the lounge on my Celestion 15XRs, whilst my normal listening room in this weather is too hot to occupy, with all the valves being used - so much so that I intend to investigate some more expensive passives, such as the Goldpoint I referred to earlier.
The Tissie has certainly been a (very welcome) eye-opener and another beneficial learning curve for me in this hobby of ours! :cool:
Marco.
Something that can be predicted by measurement is possible changes doe to impedance (mis)matching. The Tis uses 10K attenuators I believe, where for whatever reason (continuity with what I know?) I use 47k or 50K, the latter in the Tis-type attenuators I'm currently using. I can't measure and have no idea what if anything I've done to the response, but it 'sounds' fine to me. Hopefully it's mostly gain that's affected...
How would the gain be affected, Dave? I've always wondered how the 'K' value of pots or attenuators affects the gain on the amp they're connected to :)
Is 10K 'higher gain' than 50K, or if not, how does it work?
Marco.
Well I'd only measure for FR changes, as I think distortion should be pretty negligible, but yeah odd harmonics are supposed to sound "hard". I just can't see a potentiometer generating much in that direction though. I didn't think the Tizzer sounded harsh just possibly a bit brighter accounting for the "more etched" perception. But who knows. My Alps I believe is 50K versus the 10K Tizz.Quote:
Originally Posted by Macca
Much depends on impedance ratios and it seems to be a less than trivial topic. I'm not really into electronics in any way so I am not qualified to comment.
Of course the Tizzer should sound "tizzy". It's only logical:D
I know exactly where your coming from regards valve heat in summer. Keep me nice and warm in winter but high summer temperatures are another issue.Quote:
Originally Posted by Marco
Regards
Steve
I may be completely wrong on this (I usually am) but I understand the basic principle of a passive to be that of a voltage divider and therefore reductive (i.e. there is no 'gain' involved but the opposite) As the gain of the power amp is fixed it is not affected but simply supplied with a lowered voltage to work with depending on the pot position. Whether the pot is 10k or 50k will only affect the sweep of the voltage/volume curve.Quote:
Originally Posted by Marco
I have experimented with various values with my DIY passives (using traditional Alps pots) and found 10k to be the most useful with my Quad 303 and typical 'modern' output levels.
Yeah, gain is the wrong term, but you know what I mean.Quote:
Originally Posted by mikmas
By "sweep of the voltage/volume curve" do you mean how loud the sound gets in relation to the travel of the volume control? For example the sound level, with a 10k pot, at the '9 o'clock' position on a preamp, will be louder or quieter than that of a 50k pot at the same position?
If I'm talking bollocks, just say so, as I'm trying to learn :)
Marco.
You're talking bollocks. Yeah :yay: I've always wanted to say that :rofl:
Seriously the "sweep of the voltage/volume curve" is called the law, it is usually linear or logarithmic from one end to the other. The value of the track will make no difference to the equal loudness position.
Logarithmic pots are used for volume control because the sensitivity of the ear varies with sound level, as shown by the Fletcher-Munson curves:
https://upload.wikimedia.org/wikiped...indos4.svg.png
If you had a linear pot as the volume control all the adjustment would appear to be squashed at the top end.
:)
Hehehehe... Thought I'd give you the opportunity! :DQuote:
Originally Posted by Firebottle
As for the rest of the above, I'm afraid that it flies right over my big daft dome........
Marco.
OK you big daft nut. As you are keen to learn.
For a linear law pot, turn it 20% round and the tapping point (the output) will be at 20%. Turn it 50% and the output will be 50% etc.
These type of pots are used for bass and treble controls as an example.
For control of volume the increase in output needs to be quite small at the beginning but becoming a lot greater towards the top end, because the ear has a logarithmic response to sound level:
http://www.learnabout-electronics.or...log_action.gif
This is so that we can achieve sensible apparent changes to sound level over the full travel of the pot.
:D
Sorry chaps, I got it all wrong :( I must admit I have compared 10k pots to 47k ones and couldn't hear differences, for reasons now carefully explained to me. It was not my intention to mislead or cause more confusion and I'd best not try to say more in case I impart more incorrect advice.Quote:
Originally Posted by Marco