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audio-talk
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SteveTheShadow
Needs to get out more
Joined: 29 May 2007
Posts: 1734
Location: South Yorks
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 Posted: Sat Feb 20, 2010 10:05 pm Post subject: |
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I like the early Shadows stuff, and for that matter early Cliff too.
Heard through valves, via vinyl, the sound quality is often superb.
non of 'yer tinny modern stuff there.
Mind you during the rise of British R&B, the Stones et al wanted the
total opposite to that clean, sumptuous sound of Cliff & The Shads;
dirty distorted and LOUD was what they wanted, much to the bafflement of the old recording engineers who wanted to eliminate distortion.
Dirty distorted and EVEN LOUDER are all many of today's pop engineers know how to
do. They couldn't make a clean recording if their lives depended on it.
_________________
Van Gogh did some eyeball pleasers,
He must 'ave been a pencil squeezer.
He didn't do the Mona Lisa,
That was an Italian Geezer.
There ain't half been some clever bastards.... Ian Dury (1942 - 2000) |
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cressy
Old Hand
Joined: 03 Aug 2007
Posts: 1054
Location: south yorkshire
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| Posted: Sat Feb 20, 2010 10:11 pm Post subject: |
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i hear that, that snow patrol at steves last week was bloody 'orrible even through the px25s. the lou reed was most definitely not. quite an ear opener that has prompted me to keep typing 'globes into fleabay..................................................................bugger..........................................  not again
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he says they've got mansions in heaven,
yeah the angels are building one for me right now
so i know
they're saving the best for last |
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Mike H
No idea why I do this anymore
Joined: 04 Oct 2008
Posts: 6630
Location: East Anglia, or Darn Sarf and then left a bit
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| Posted: Sun Feb 21, 2010 10:52 am Post subject: |
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| SteveTheShadow wrote: | Dirty distorted and EVEN LOUDER are all many of today's pop engineers know how to
do. They couldn't make a clean recording if their lives depended on it. |
Bet they could, just that they're told by the execs it's got to be more attention grabbing than the opposition's "musical" products
.
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Mike H
No idea why I do this anymore
Joined: 04 Oct 2008
Posts: 6630
Location: East Anglia, or Darn Sarf and then left a bit
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| Posted: Sun Feb 21, 2010 10:59 am Post subject: |
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| Andrew wrote: | Could you make the 1.5v from the 3v? Use a low voltage adjustable shunt perhaps?
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As they're for separate DHT's I've got a horrible feeling they also all need to be electrically separate, so separate transformer windings as well 
Unless Steve knows differently 
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Mike H
No idea why I do this anymore
Joined: 04 Oct 2008
Posts: 6630
Location: East Anglia, or Darn Sarf and then left a bit
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| Posted: Sun Feb 21, 2010 12:13 pm Post subject: |
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Summink like this innit ~
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SteveTheShadow
Needs to get out more
Joined: 29 May 2007
Posts: 1734
Location: South Yorks
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| Posted: Sun Feb 21, 2010 1:42 pm Post subject: |
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| Mike H wrote: | | Andrew wrote: | Could you make the 1.5v from the 3v? Use a low voltage adjustable shunt perhaps?
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As they're for separate DHT's I've got a horrible feeling they also all need to be electrically separate, so separate transformer windings as well
Unless Steve knows differently |
Why do you think I used batteries for the filaments 
In this version I don't want the hassle of having to change and recharge batteries.
Bit of a miscalculation on the filament voltages required. It is 4 x 1.5V supplies. The way Mr Nizhegorodov has connected the supplies are such that for the second double triode there is, in effect, 1.5V standing at one end of the filament and 3V at the other to provide two different levels of battery bias on the common cathodes.
It's that ingenious I still get confused. But he says it was done like this years ago in the battery powered portable radio sets for which these little DHTs were intended.
I know Will had a helluva job trying to get the isolation needed. Hopefully the four separate 1.5V supplies will behave like four separate batteries.
The PSU is undeniably going to be the challenging part of this construction
Let's see:
Four regulated LT supplies for the DHTs
One regulated LT supply for the first stage valve.
Three regulated HT supplies, one for each DHT
One regulated HT supply for the first stage valve
Two transformers with 2X6V secondaries, one for each DHT
One transformer with 9V secondaries for the first stage.
One HT transformer 150-0-150 able to provide the HT for the whole shebang. (180v, 140V and 120V and 80V)
RF and common-mode noise rejection all built in too.
one might say that four HT supplies are unnecessary but OTOH I might as well give it the best chance of sounding fab.
Steve
_________________
Van Gogh did some eyeball pleasers,
He must 'ave been a pencil squeezer.
He didn't do the Mona Lisa,
That was an Italian Geezer.
There ain't half been some clever bastards.... Ian Dury (1942 - 2000) |
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floppybootstomp
Old Hand
Joined: 18 Feb 2009
Posts: 485
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| Posted: Sun Feb 21, 2010 3:23 pm Post subject: |
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| SteveTheShadow wrote: |
Dirty distorted and EVEN LOUDER are all many of today's pop engineers know how to
do. They couldn't make a clean recording if their lives depended on it. |
Alert! Alert!
Old man waffling at the bustop syndrome 
Oh aye it were better in our day our kid....
I would venture the opinion, in the nicest possible way, that the above quoted sentiment is the product of bovine defecation.
There are oodles of good clean recordings about made during the last decade.
And FWIW I've always liked the Shadows, first record I ever bought was actually 'Wonderful Land'.
But I've always thought Cliff was a bit of a div
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Mike H
No idea why I do this anymore
Joined: 04 Oct 2008
Posts: 6630
Location: East Anglia, or Darn Sarf and then left a bit
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| Posted: Sun Feb 21, 2010 5:57 pm Post subject: |
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| SteveTheShadow wrote: | Why do you think I used batteries for the filaments
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There you are!
| Quote: | The way Mr Nizhegorodov has connected the supplies are such that for the second double triode there is, in effect, 1.5V standing at one end of the filament and 3V at the other to provide two different levels of battery bias on the common cathodes.
It's that ingenious I still get confused.
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Yes I'm still trying to figure it out!
OK looked at the cct a few minutes, think I got it. You've got
-[1.5V]+ -[1.5V]+
batteries in series ~ V1 is powered by the first one, and V2 by the second, BUT, V2 heater cct is lifted by 1.5V by being on top of the first one. It's made even more confusing to look by each cathode halves are in parallel.
| Quote: | Two transformers with 2X6V secondaries, one for each DHT
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Yes I thought so. What's the current?
| Quote: | One transformer with 9V secondaries for the first stage.
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Seems about right
| Quote: | one might say that four HT supplies are unnecessary but OTOH I might as well give it the best chance of sounding fab.
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Not dropper resistors then off same HT source?
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Andrew
Shed dweller
Joined: 24 May 2007
Posts: 2320
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| Posted: Sun Feb 21, 2010 6:12 pm Post subject: |
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Why do you think I used batteries for the filaments Laughing
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There you are! Very Happy
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Hang, maybe I'm missing something here, but how does the valve know what's behind the regulator?
-- Andrew
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SteveTheShadow
Needs to get out more
Joined: 29 May 2007
Posts: 1734
Location: South Yorks
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| Posted: Sun Feb 21, 2010 6:24 pm Post subject: |
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Hi Mike
OK the filaments take 220mA each so with four transformer windings available that's 220mA per winding for the DHTs.
| Quote: | | no dropper resistors then off the same HT source? |
As I inferred, I'm unsure as to whether to use dropper resistors like I am doing in the present PSU or to go for separate supplies for each pair of valves, regulated to the appropriate voltages for each.
I could go down to two supplies, one for the HT to the input stage and the other supplying the highest voltage (140V to the output stage with the other two derived from droppers.)
I suppose it would be quiet enough as the one DHT supply would have already been regulated.
Are there any advantages to going separate for the three stages of DHT?
I know Naim swear by separate regs for each supply. there can be up to 24 in some of their gear, and having heard the difference a Hi-Cap
(or whatever they call it these days) makes, I know the differences can be far from subtle.
Has anyone compared single supplies with drop off branches with separate arrangements.
I suppose it's star powering as opposed to star earthing.
Dunno
Steve
_________________
Van Gogh did some eyeball pleasers,
He must 'ave been a pencil squeezer.
He didn't do the Mona Lisa,
That was an Italian Geezer.
There ain't half been some clever bastards.... Ian Dury (1942 - 2000) |
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SteveTheShadow
Needs to get out more
Joined: 29 May 2007
Posts: 1734
Location: South Yorks
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| Posted: Mon Feb 22, 2010 11:06 pm Post subject: |
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OK a bit further on now
Here is a proposed HT regulated supply for one of the pairs of DCC90s;
this courtesy of a National Semiconductor application paper (I'm not clever enough to do my own,
or that inclined to reinvent the wheel  )
Four of these will supply 140V, 120V, 80V and up to 160V for the input valve
which will most likely be a 5687, 7044 or 6463.
I'll use four of Mike's 1.5V DC regulated supplies for the DHT filaments
plus another single 6.3V dc regulated supply for the input valve (whichever one I choose)
That makes nine altogether. Very Naim-like. 
Steve
_________________
Van Gogh did some eyeball pleasers,
He must 'ave been a pencil squeezer.
He didn't do the Mona Lisa,
That was an Italian Geezer.
There ain't half been some clever bastards.... Ian Dury (1942 - 2000) |
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Mike H
No idea why I do this anymore
Joined: 04 Oct 2008
Posts: 6630
Location: East Anglia, or Darn Sarf and then left a bit
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| Posted: Tue Feb 23, 2010 12:21 am Post subject: |
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Sorry only just seen this!
| Andrew wrote: | Hang, maybe I'm missing something here, but how does the valve know what's behind the regulator?
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I believe it doesn't ~ hopefully the desired result is that the regulated output (+ & –) looks like just another battery
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Last edited by Mike H on Tue Feb 23, 2010 12:43 am; edited 1 time in total |
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Mike H
No idea why I do this anymore
Joined: 04 Oct 2008
Posts: 6630
Location: East Anglia, or Darn Sarf and then left a bit
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| Posted: Tue Feb 23, 2010 12:38 am Post subject: |
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| SteveTheShadow wrote: | OK a bit further on now
Here is a proposed HT regulated supply for one of the pairs of DCC90s;
this courtesy of a National Semiconductor application paper (I'm not clever enough to do my own,
or that inclined to reinvent the wheel )
Four of these will supply 140V, 120V, 80V and up to 160V for the input valve
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If you don't mind a weensy bijou observation
That seems very involved TBH
I'm also worried that the ratio of the LM317 resistors is very large, very small between OUT and Adj., very large between Adj. and GND. So I'm guessing probably float about somewhat, cos the feedback isn't good enough. Nor for smoothing either possibly
What I would do, if you're asking me,
100k bias resistor like you got, then into the gate of a power MOSFET, then a chain of Zeners to GND to fix it.
Four of them in a row on a bit of a bracket or something, bit of matrix board to put the resistors and zeners on, seemples!
Job done innit
NB plus, if your heaters are only 220mA, then the 2 x 6V transformers could be very small and cheap, if say 500mA per winding. So miniature type
.
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Mike H
No idea why I do this anymore
Joined: 04 Oct 2008
Posts: 6630
Location: East Anglia, or Darn Sarf and then left a bit
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| Posted: Tue Feb 23, 2010 12:48 am Post subject: |
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| Mike H wrote: | Sorry only just seen this!
| Andrew wrote: | Hang, maybe I'm missing something here, but how does the valve know what's behind the regulator?
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I believe it doesn't ~ hopefully the desired result is that the regulated output (+ & –) looks like just another battery |
Oh wait I know what you mean ~ well because, the heating current is much larger than the cathode current. So I guess the total "battery" current is the heating current, minus the cathode current.
If that makes sense.
I know what I mean
.
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colin.hepburn
Old Hand
Joined: 02 Jun 2007
Posts: 937
Location: Scotland Aberdeenshire
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