A unipivot made from scrap
- izzy wizzy
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#271 Re: A unipivot made from scrap
Or could there be a phono EQ difference down low?
#272 Re: A unipivot made from scrap
I dont think its that the schroeder is bass light, your digital side should be flat so if you have set your levels using a combination of the 401 and the digital side they should be pretty flat
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#273 Re: A unipivot made from scrap
I used the same PHONO II with a 39k load resistor, so should be close enough with Ant's MM cart?
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#274 Re: A unipivot made from scrap
This is the uncertainty in my mind. Since I built these speakers I've been listening to vinyl exclusively, apart from maybe when they were first built. So what I perceive as "normal" might not be.
It's not easy to switch between vinyl and digital but I need to find the same album on both and see how they compare.
#275 Re: A unipivot made from scrap
The 39k in your phono 2 is not far off the 47k in my benedict audio, i cant see there being a great deal of difference with the loads
Its at the old mans house at the moment, so we shall see what he reckons compared to the mk 5 and mk 6 versions
The one thing i didnt address is the handling which he didnt like with the mk5, in fact i made it worse with the little fingerlift
I could really do with some other carts to try on it, or to be tried on it, the dynavector isnt that typical a cartridge
Its at the old mans house at the moment, so we shall see what he reckons compared to the mk 5 and mk 6 versions
The one thing i didnt address is the handling which he didnt like with the mk5, in fact i made it worse with the little fingerlift
I could really do with some other carts to try on it, or to be tried on it, the dynavector isnt that typical a cartridge
- izzy wizzy
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#276 Re: A unipivot made from scrap
Stiff string?
- Cressy Snr
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#277 Re: A unipivot made from scrap
Been listening to the new arm:
It sounds very good, more evenly balanced through the frequency range. Treble is detailed but remains smooth with the Dynavector MC cartridge. There is a slight hint of mid-forwardness coming through that wasn’t there on the earlier iteration. This combined with the tuneful, articulate bottom end makes it sound even more like a Naim Aro. This characteristic gives a sense of no nonsense power and solidity to the presentation. No thinness or lack of dynamics. It’s bloody good in my opinion.
Still don’t like the position of the fingerlift. It might be worth incorporating it into the side of the circular cartridge mounting platform; that way it will stick out at right angles to the cartridge itself rather than at right angles to the arm tube. This should make handling a lot easier.
It sounds very good, more evenly balanced through the frequency range. Treble is detailed but remains smooth with the Dynavector MC cartridge. There is a slight hint of mid-forwardness coming through that wasn’t there on the earlier iteration. This combined with the tuneful, articulate bottom end makes it sound even more like a Naim Aro. This characteristic gives a sense of no nonsense power and solidity to the presentation. No thinness or lack of dynamics. It’s bloody good in my opinion.
Still don’t like the position of the fingerlift. It might be worth incorporating it into the side of the circular cartridge mounting platform; that way it will stick out at right angles to the cartridge itself rather than at right angles to the arm tube. This should make handling a lot easier.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
#278 Re: A unipivot made from scrap
Interesting... just been looking at dl103's while looking for carts. As we know, they have have a compliance of 5, and i suddenly remembered that that figure was arrived at measured at 100hz. So its not 5, its somewhere around 9 ish at 10hz. Hence looki g at them at all.
I then found an article that martin colloms did and he reckoned it came in at 12x10-6 at 10hz. Presumably this was calculated using a test record
That, coupled with this arms effective mass of 12.6g with an 8g cart, gives a resonance of 9hz, smack in the middle of the green zone on the vinyl engine resonance evaluator
So a 103 will work fine in this arm. Shame they have a spherical stylus......
I then found an article that martin colloms did and he reckoned it came in at 12x10-6 at 10hz. Presumably this was calculated using a test record
That, coupled with this arms effective mass of 12.6g with an 8g cart, gives a resonance of 9hz, smack in the middle of the green zone on the vinyl engine resonance evaluator
So a 103 will work fine in this arm. Shame they have a spherical stylus......
- IslandPink
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#279 Re: A unipivot made from scrap
Hmm, 9Hz is still adding a bass roll-off though. Anyone who's used one for a while knows that extra mass helps a lot. I think James went as far as a 50p piece blu-tacked to the headshell on his Kenwood.
It's interesting to hear the compliance numbers for 10Hz and 100Hz though, thanks.
It's interesting to hear the compliance numbers for 10Hz and 100Hz though, thanks.
"Once you find out ... the Circumstances ; then you can go out"
- pre65
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#280 Re: A unipivot made from scrap
I used a 20p piece.IslandPink wrote: ↑Thu Jul 15, 2021 1:08 pm Hmm, 9Hz is still adding a bass roll-off though. Anyone who's used one for a while knows that extra mass helps a lot. I think James went as far as a 50p piece blu-tacked to the headshell on his Kenwood.
It's interesting to hear the compliance numbers for 10Hz and 100Hz though, thanks.
The only thing necessary for the triumph of evil is for good men to do nothing.
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G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#281 Re: A unipivot made from scrap
On this arm the brass mounting plate is what adds the weight
Because it is directly over the top of the cart, and moves with the cart when it is aligned, i have to calculate the plate in with the cart weight rather than as a headshell. It does interesting things to the calculation if you add it in as a headshell, the calculation assumes that a headshell is in a fixed position and adds it to the bare arm mass. This is to compensate for headshells of different weights.
So working it out for this arm i have to treat it as a fixed headshell arm with additional weight added to the cart itself.
If the resonance of the arm is at 9hz (or whatever figure it might be), i wouldnt see that as a rolloff, id see it as an LF spike at that point as the arm adds its contribution, like the fr of a speaker cone when you see a hump in the plots at the fr point,or am i wrong in thinking this?
Need to work out some way of measuring without an accelerometer available
Because it is directly over the top of the cart, and moves with the cart when it is aligned, i have to calculate the plate in with the cart weight rather than as a headshell. It does interesting things to the calculation if you add it in as a headshell, the calculation assumes that a headshell is in a fixed position and adds it to the bare arm mass. This is to compensate for headshells of different weights.
So working it out for this arm i have to treat it as a fixed headshell arm with additional weight added to the cart itself.
If the resonance of the arm is at 9hz (or whatever figure it might be), i wouldnt see that as a rolloff, id see it as an LF spike at that point as the arm adds its contribution, like the fr of a speaker cone when you see a hump in the plots at the fr point,or am i wrong in thinking this?
Need to work out some way of measuring without an accelerometer available
- IslandPink
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#282 Re: A unipivot made from scrap
Maybe I'm wrong in describing it as a roll-off yes, it's a resonance peak.
So, the resonance peak has an increasing phase shift associated with it, as you go down from upper bass into the low bass - which will affect the perceived timing and quality of the bass.
So, the resonance peak has an increasing phase shift associated with it, as you go down from upper bass into the low bass - which will affect the perceived timing and quality of the bass.
"Once you find out ... the Circumstances ; then you can go out"
#283 Re: A unipivot made from scrap
The only difference between the two is the Q of the system. Below the peak it will be a roll off. The Q governs how abrupt the phase change is.Maybe I'm wrong in describing it as a roll-off yes, it's a resonance peak.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#284 Re: A unipivot made from scrap
Did a little more work on the arm, made a heavier counterweight. I did try adding some lead to the existing one but it altered the mass distribution of the counterweight and did strange things to the lateral balance so i sacked that and did it properly with some more steel.
If anyone wants some stick on lead strip let me know, my father in law gave me 2 huge great rolls of it from when he was doing leaded windows. Theres about 5 kilos of it.....
The new one is 150g as opposed to 115g, and took an inordinate amount of time to make with the amount of times i took it out of the lathe chuck and weighed it, faced some more off it, and buggered about boring the centre hole to fit the stub.
Thats because id not used 10mm polished bar stock and had turned down what i had in to make the stub..
It will drop the effective mass a little to 11.5 g with the dv in it.
I have some more brass coming to make a smaller one of the same weight, id prefer it was more compact.
Havent listened to it yet, i dont think it will make a great deal of difference though, but it looks better not hanging off the end of the stub
Onwards!
If anyone wants some stick on lead strip let me know, my father in law gave me 2 huge great rolls of it from when he was doing leaded windows. Theres about 5 kilos of it.....
The new one is 150g as opposed to 115g, and took an inordinate amount of time to make with the amount of times i took it out of the lathe chuck and weighed it, faced some more off it, and buggered about boring the centre hole to fit the stub.
Thats because id not used 10mm polished bar stock and had turned down what i had in to make the stub..
It will drop the effective mass a little to 11.5 g with the dv in it.
I have some more brass coming to make a smaller one of the same weight, id prefer it was more compact.
Havent listened to it yet, i dont think it will make a great deal of difference though, but it looks better not hanging off the end of the stub
Onwards!
#285 Re: A unipivot made from scrap
Decided to try an aluminium bearing housing instead of the acetal one.
Cx unipivot version 7/a by anthony cresswell, on Flickr
The carbon fibre tube and aluminium stub and headshell is off the one that our Simon assessed, I'll make a new pillar as I have another v jewel. I'll also make a new outrigger set instead of using the one off that version as I reckon there's some odd resonances coming from it. The wiring and mdin socket will also be reused from the version 6 arm
The reason I've decided to look at a metal housing is that I think that the acetal is blocking the path for some resonances to get out of the tube and down the arm pillar, and having some aluminium to play with, it seemed a reasonable thing to try.
The housing is exactly the same as the acetal one, and has a brass weight insert in it instead of a steel one to compensate for the heavier weight of the metal.
Cx unipivot version 7/a by anthony cresswell, on Flickr
I'll also need to make another mounting boss and cartridge carrier, should have enough aluminium left for those
I've also been kindly loaned an Ortofon 2m blue to try on this arm and the brass version so I'll be able to see how they behave with something other than the Dynavector in them which should give me more of a overview of what traits the arm is adding to the whole.
This version will go on the big Lenco so I can kind of A/B then on practically the same deck.
I'll also need another cable, I've been looking for something that has a reasonable cost, found one by a firm called the vinyl adventure, one called 'the rebel'. £40 is at least reasonable
Onwards!
Cx unipivot version 7/a by anthony cresswell, on Flickr
The carbon fibre tube and aluminium stub and headshell is off the one that our Simon assessed, I'll make a new pillar as I have another v jewel. I'll also make a new outrigger set instead of using the one off that version as I reckon there's some odd resonances coming from it. The wiring and mdin socket will also be reused from the version 6 arm
The reason I've decided to look at a metal housing is that I think that the acetal is blocking the path for some resonances to get out of the tube and down the arm pillar, and having some aluminium to play with, it seemed a reasonable thing to try.
The housing is exactly the same as the acetal one, and has a brass weight insert in it instead of a steel one to compensate for the heavier weight of the metal.
Cx unipivot version 7/a by anthony cresswell, on Flickr
I'll also need to make another mounting boss and cartridge carrier, should have enough aluminium left for those
I've also been kindly loaned an Ortofon 2m blue to try on this arm and the brass version so I'll be able to see how they behave with something other than the Dynavector in them which should give me more of a overview of what traits the arm is adding to the whole.
This version will go on the big Lenco so I can kind of A/B then on practically the same deck.
I'll also need another cable, I've been looking for something that has a reasonable cost, found one by a firm called the vinyl adventure, one called 'the rebel'. £40 is at least reasonable
Onwards!