6SN7 Mu Follower Distortion Paper
Ian Bell
mu follower and posted it at my website. You can read it here:
http://www.ianbell.ukfsn.org/data/mufollowerdistortion.pdf
Cheers
Ian
Patrick Turner
Its not clear how you would go about biasing the bottom triode with Eg =
-3V while keeping Ia at 8 mA.
Anyway, maybe you'd get even lower THD if you had Ia = 4mA, and bias at
about -5V for both top and bottom tubes with identical Rk used to
develop the bias voltage. This way the working Ea for top and bottom
triodes will be equal and each about 137Vdc.
You'll get
If you have Idc = 4mA, Ea = 137, the load line for the bottom triode
which "sees" a load approx 200k shows that the negative going anode
swing is from 137V down about 85pkV before grid current so the max Vrms
output should be in excess of 58Vrms, a lot more than what you have
described.
About 54Vrms should be able to be applied to the 100k RL and the load
current change is a small 0.54mA rms.
Its awhile since I did experiments on µ-followers, but generally THD can
be a lot less than 1/2 what you'd get if the bottom triode had only a
load R to replace the top triode acting as a follower and buffer between
the bottom triode and the load. In fact, if the top triode was
abolished, the RLdc required would be 47k, and that in parallel with the
100k load gives a final RL = 32k. Expect THD to be 3 times what you have
with an active load as you show in your schematic which is approximately
10k x top triode gain of 18.5 = 185k which is about 20Ra.
Some people use a j-fet CCS to replace your R1 10k. This makes the
bottom triode see a very high value ac load and thus THD is about
reduced to near the minimum that is possible to get.
For measuring noise in such a circuit, the bottom grid should be taken
to 0V via a short lead. This means the noise of R4 120k isn't injected
into the tube. Such resistor noise would be much higher than what the
grid input noise should be. You should have only about 2uV grid input
noise, and this is amplified about 18 times to become 36uV at the bottom
anode. DC must be used on heaters to achieve this. Additional noise is
generated in the C1 & R3 circuit because as F lowers, the LF noise of
R3 is applied to the top triode follower. I think 0.47uF plus 220k might
give better results for noise.
But its not a huge deal because the top triode should not contribute
much noise as it is a follower with gain just under 1.0.
Noise is generated in R1, 10k, and one has to be careful about leakage
currents between cathode and heaters if the dc difference is high.
All up, anything less than 50uV at the output would be OK.
Patrick Turner.
Ian Bell
>
> Ian Bell wrote:
>> I have written up the work I did on investigating distortion in a 6SN7
>> mu follower and posted it at my website. You can read it here:
>>
>> http://www.ianbell.ukfsn.org/data/mufollowerdistortion.pdf
>>
>> Cheers
>>
>> Ian
>
> Its not clear how you would go about biasing the bottom triode with Eg =
> -3V while keeping Ia at 8 mA.
>
Sorry, I don't see the problem - a 430R cathode resistor sits you pretty
much on that spot.
> Anyway, maybe you'd get even lower THD if you had Ia = 4mA, and bias at
> about -5V for both top and bottom tubes with identical Rk used to
> develop the bias voltage. This way the working Ea for top and bottom
> triodes will be equal and each about 137Vdc.
I already tried you idea of running both triodes at 5mA and -5V bias and
I get identical distortion figures. The 6CG7 seems pretty relaxed about
operating point.
> You'll get
>
> If you have Idc = 4mA, Ea = 137, the load line for the bottom triode
> which "sees" a load approx 200k shows that the negative going anode
> swing is from 137V down about 85pkV before grid current so the max Vrms
> output should be in excess of 58Vrms, a lot more than what you have
> described.
>
That is not surprising - if you raise the grid bias from -3.4V to -5V
you would expect higher output before the onset of grid bias distortion.
However, the lower standing current lowers the drive capability of the
output.
I am not quite sure what point you are making. I did the tests at 8mA
and around 3V bias - grid current occurred at the expected input level.
Morgan Jones reckons the 6SN7 exhibits its lowest distortion at 8mA. He
does not qualify that statement though.
> About 54Vrms should be able to be applied to the 100k RL and the load
> current change is a small 0.54mA rms.
>
> Its awhile since I did experiments on ľ-followers, but generally THD can
> be a lot less than 1/2 what you'd get if the bottom triode had only a
> load R to replace the top triode acting as a follower and buffer between
> the bottom triode and the load. In fact, if the top triode was
> abolished, the RLdc required would be 47k, and that in parallel with the
> 100k load gives a final RL = 32k. Expect THD to be 3 times what you have
> with an active load as you show in your schematic which is approximately
> 10k x top triode gain of 18.5 = 185k which is about 20Ra.
>
> Some people use a j-fet CCS to replace your R1 10k. This makes the
> bottom triode see a very high value ac load and thus THD is about
> reduced to near the minimum that is possible to get.
>
> For measuring noise in such a circuit, the bottom grid should be taken
> to 0V via a short lead.
That is exactly what I did.
This means the noise of R4 120k isn't injected
> into the tube. Such resistor noise would be much higher than what the
> grid input noise should be. You should have only about 2uV grid input
> noise, and this is amplified about 18 times to become 36uV at the bottom
> anode. DC must be used on heaters to achieve this. Additional noise is
> generated in the C1 & R3 circuit because as F lowers, the LF noise of
> R3 is applied to the top triode follower. I think 0.47uF plus 220k might
> give better results for noise.
> But its not a huge deal because the top triode should not contribute
> much noise as it is a follower with gain just under 1.0.
>
> Noise is generated in R1, 10k, and one has to be careful about leakage
> currents between cathode and heaters if the dc difference is high.
>
> All up, anything less than 50uV at the output would be OK.
That would be nice but as you can see from the measurements I have yet
to see better than 65uV and most tubes are in the 90 to 100uV region.
Cheers
Ian
Patrick Turner
But your RL = 100k, and you don't need a huge Ia dc to get a wide Vswing
at the OP.
If you had RL = 25k, then sure, more Ia is better but the more you raise
Ia, the less swing you get...
>
> I am not quite sure what point you are making. I did the tests at 8mA
> and around 3V bias - grid current occurred at the expected input level.
The greater Iadc + lower Ea + low bias = low Vo max before THD exceeds
2%.
>
> Morgan Jones reckons the 6SN7 exhibits its lowest distortion at 8mA. He
> does not qualify that statement though.
Perhaps it does. But say you had Ea = 200V, Ia = 8mA, and you draw a
load line for 200k.
The load is nearly a CCS or horizontal loadline and you get a much wider
Vswing without THD than if you allow Ea to be say 125V only.
If that is the case, then the grid input noise is about what you are
getting at the anode divided by the gain,
so there's about 3uV to 5 uV of input noise, ( dc to 20kHz ) Good
samples of 6CG7 will yield 2uV.
Allowing BW to be wider results in more noise.
I like the ľ-foll because its inherently low THD/IMD and it does the
business well in a preamp stage of any kind; ie, it has high Z in, low Z
out and wide BW and noise which is just wnat you want a voltage amp to
have. It also sounds very nice.
And its efficient, because rather than waste watts of power in anode and
cathode feed resistors with a traditional gain stage and CF, you are
able to series tubes and save 50% or otherwise wasted power in
resistors.
Patrick Turner.
>
> Cheers
>
> Ian
Ian Bell
I am sure you read my paper right through so I am sure you noticed I did
the initial tests with 100K but also looked at how it fared into 25K and
10K loads.
>> I am not quite sure what point you are making. I did the tests at 8mA
>> and around 3V bias - grid current occurred at the expected input level.
>
> The greater Iadc + lower Ea + low bias = low Vo max before THD exceeds
> 2%.
>
Yes but greater Ia does not necessarily mean lower Ae and bias.
>
>> Morgan Jones reckons the 6SN7 exhibits its lowest distortion at 8mA. He
>> does not qualify that statement though.
>
> Perhaps it does. But say you had Ea = 200V, Ia = 8mA, and you draw a
> load line for 200k.
>
> The load is nearly a CCS or horizontal loadline and you get a much wider
> Vswing without THD than if you allow Ea to be say 125V only.
>
>
>>> About 54Vrms should be able to be applied to the 100k RL and the load
>>> current change is a small 0.54mA rms.
>>>
>>> Its awhile since I did experiments on µ-followers, but generally THD can
Which reminds me, I would be interested to know exactly what set up do
you use to measure noise.
> Allowing BW to be wider results in more noise.
>
> I like the µ-foll because its inherently low THD/IMD and it does the
> business well in a preamp stage of any kind; ie, it has high Z in, low Z
> out and wide BW and noise which is just want you want a voltage amp to
> have. It also sounds very nice.
>
> And its efficient, because rather than waste watts of power in anode and
> cathode feed resistors with a traditional gain stage and CF, you are
> able to series tubes and save 50% or otherwise wasted power in
> resistors.
>
I agree. I like them too.
Cheers
Ian
Patrick Turner
Ian Bell wrote:
>
> Patrick Turner wrote:
> >
> > Ian Bell wrote:
> >> Patrick Turner wrote:
> >>> Ian Bell wrote:
snip for brevity,
>
> >> I am not quite sure what point you are making. I did the tests at 8mA
> >> and around 3V bias - grid current occurred at the expected input level.
> >
> > The greater Iadc + lower Ea + low bias = low Vo max before THD exceeds
> > 2%.
> >
>
> Yes but greater Ia does not necessarily mean lower Ae and bias.
In your circuit between +325V and 0V you have two tubes in series with
about 10k between them plus two Rk.
So higher Ia means more voltage across the R and less across the tubes
so there is less negative going anode V swing and more THD.
Sure you can raise tha Ia and raise the Ea, while increasing grid bias
and allowing a much wider Va swing well away from GI.
But you'd run out of headroom unless you make the B+ maybe 550V instead
of only 325V.
With only +325V available, you can try an 8 mA CCS to the anode which
might run at 200V and direct couple that to a CF with CCS 8 mA cathode
sink. The CF cathode will be at about +160V, and there's 155V of
headroom for the CF.
But at least with a gain tube followed by a CF you eliminate the V drop
wasted on the top Rk = 10k.
snip,
I have a test circuit with heater dc, and stable well filtered B+ supply
and have the tube under test with grid to 0V.
Bias is adjusted for about right by switching the anode load between 3
values, 22k, 47k, and 100k.
Cathode is bypassed with 1,000 uF.
The noise voltage appearing at the anode due to the load resistance is
negligible compared to the noise generated by the tube, principally the
grid input noise from the equivalent grid input noise resistance. And
the anode resistance of many triodes shunts the noise voltage of the
higher value load resistance.
To amplify the noise at the anode of the tube under test I use a 2 stage
cascaded tube amp with 6DJ8 followed by 12AT7 with gain approx 1,500.
Input Z is high so the Bandwidth of this amp is deliberately chosen for
about 2Hz to 20kHz, -3dB. Then there's a gain pot and finally a 12AU7 CF
output that is taken to a CRO and volt meter.
Sometimes I run the noise signal to a power amp with speaker to estimate
the least microphonic and noisy tubes and the nature of the noise.
When you test a batch of 10 tubes, you'll soon see some are better than
others. The best have a good hard vacuum and little gas inside and have
tight mica supports to the electrodes. Old worn tubes get loosened mica
grip on electrodes and they become microphonic as a result.
Old tubes also develop sputtery noise with high LF content, probably due
to gassiness.
So suppose I have a 12AU7 under test. Gain might be 12 when I measure
it. Suppose the grid noise = 2uV, then noise at anode = 24uV. Then this
is amplified x 1,500 times to become 36mV, and this is measured and
displayed on the CRO. I can tell immediately how much noise the testing
amp makes by merely grounding its input. 2uV at its input becomes only
3mV at its output, far less than the preceding TUT, and it can be
ignored.
Feel free to use a garden variety opamp with FB loop to set the gain to
over 1,000.
Every dude selling second hand tubes and NOS tubes ( which may not be
NOS at all, but favourite well used audiophile tubes ) should test the
tubes they sell as I suggest. If not, then only pay for NOS tubes
**after** you have recieved them in the mail and tested them yourself.
If noisy, send them back to the seller, no hard feelings.
Patrick Turner.
> Which reminds me, I would be interested to know exactly what set up do
> you use to measure noise.
>
> > Allowing BW to be wider results in more noise.
> >
> > I like the ต-foll because its inherently low THD/IMD and it does the
Ian Bell
>
> Ian Bell wrote:
>> Patrick Turner wrote:
>>> Ian Bell wrote:
>>>> Patrick Turner wrote:
>>>>> Ian Bell wrote:
>
> snip for brevity,
>>>> I am not quite sure what point you are making. I did the tests at 8mA
>>>> and around 3V bias - grid current occurred at the expected input level.
>>> The greater Iadc + lower Ea + low bias = low Vo max before THD exceeds
>>> 2%.
>>>
>> Yes but greater Ia does not necessarily mean lower Ae and bias.
>
> In your circuit between +325V and 0V you have two tubes in series with
> about 10k between them plus two Rk.
>
> So higher Ia means more voltage across the R and less across the tubes
> so there is less negative going anode V swing and more THD.
>
Yes but 8mA and -3.4V gives Ea about 140 and 50v across the 10K and ytou
won't get grid current until over 40V rms out.
With 5mA, -5V bias this rises to about 65V rms.
A lot depends on the application but for me, 40V rms gives a good 20dB
headroom over normal operating levels.
> Sure you can raise tha Ia and raise the Ea, while increasing grid bias
> and allowing a much wider Va swing well away from GI.
> But you'd run out of headroom unless you make the B+ maybe 550V instead
> of only 325V.
>
I don't think so - see above - but again it depends on the application -
as I have said many times before, I am a preamp chap and 40V rms max
gives me plenty of headroom.
Cheers
Ian
Patrick Turner
Indeed. Keep up the good work and as they say,
keep the home triodes burning,
Patrick Turner.
Iain Churches
"Ian Bell" <ruffr...@yahoo.com> wrote in message
news:gktetl$dka$1...@localhost.localdomain...
>I have written up the work I did on investigating distortion in a 6SN7 mu
>follower and posted it at my website. You can read it here:
>
> http://www.ianbell.ukfsn.org/data/mufollowerdistortion.pdf
>
Ian. Excellent paper.
You mentioned that you had, or were in the process
of acquiring, a HP spectrum analyser to examine the
differences between the distortion profile of the
different valves/tubes that you had tested.
Have you done this analysis yet? Some pics would be of
interest.
Most 6CG7s that I have evaluated have similar THD
values, and yet in comparison tests, Westinghouse
and Telefunken are usually picked out as sounding
the best. Perhaps THD does not tell us the full story.
Best regards
Iain
Ian Bell
> "Ian Bell" <ruffr...@yahoo.com> wrote in message
> news:gktetl$dka$1...@localhost.localdomain...
>> I have written up the work I did on investigating distortion in a 6SN7 mu
>> follower and posted it at my website. You can read it here:
>>
>> http://www.ianbell.ukfsn.org/data/mufollowerdistortion.pdf
>>
>
> Ian. Excellent paper.
>
> You mentioned that you had, or were in the process
> of acquiring, a HP spectrum analyser to examine the
> differences between the distortion profile of the
> different valves/tubes that you had tested.
>
> Have you done this analysis yet? Some pics would be of
> interest.
>
Not yet - I am at present struggling to get a twin T notch filter
working properly so I can measure the individual harmonics. However, I
can say from some initial tests without the twin T that at 20V rms the
2H level is close to -50dB, the 3H seems to be around -75dB and the
third is below what my instrument will measure. So the contention that
it is 'mainly second harmonic' would seem to be true.
As for pictures, the device I have bought is an HP 3581A Wave Meter - it
is in effect a spectrum analyser but not with a PC interface for
capturing nice pictures. You can connect it to a scope but as its scan
rate is of the order of seconds you wont see much on a scope unless it
is a storage type and mine isn't - it will interface directly to a pen
plotter though!!!! I have seen a suggestion of using it with a USB data
capture device but one of these costs more than I paid for the HP ;-) so
for the present it will just have to be done by hand.
OTOH a cheap PC interface type scope might do the trick.
> Most 6CG7s that I have evaluated have similar THD
> values, and yet in comparison tests, Westinghouse
> and Telefunken are usually picked out as sounding
> the best. Perhaps THD does not tell us the full story.
>
I am sure it does not. It is a start and the spectral shape of the
harmonics is the second step. After that it is looking at
intermodulation distortion which I can also do on the HP.
Cheers
ian
Ian Bell
> take is some patch cables to see.
>
I have tried a couple of those that use your PC soundcard on my laptop.
Could not get either one of them to work properly - probably something
to do with the sound chip but it is a new laptop.
No I was thinking more of those that plug into a usb port and have some
external = decent electronics.
Cheers
Ian
Patrick Turner
Ian Bell wrote:
>
> Iain Churches wrote:
> > "Ian Bell" <ruffr...@yahoo.com> wrote in message
> > news:gktetl$dka$1...@localhost.localdomain...
> >> I have written up the work I did on investigating distortion in a 6SN7 mu
> >> follower and posted it at my website. You can read it here:
> >>
> >> http://www.ianbell.ukfsn.org/data/mufollowerdistortion.pdf
> >>
> >
> > Ian. Excellent paper.
> >
> > You mentioned that you had, or were in the process
> > of acquiring, a HP spectrum analyser to examine the
> > differences between the distortion profile of the
> > different valves/tubes that you had tested.
> >
> > Have you done this analysis yet? Some pics would be of
> > interest.
> >
>
> Not yet - I am at present struggling to get a twin T notch filter
> working properly so I can measure the individual harmonics. However, I
> can say from some initial tests without the twin T that at 20V rms the
> 2H level is close to -50dB, the 3H seems to be around -75dB and the
> third is below what my instrument will measure. So the contention that
> it is 'mainly second harmonic' would seem to be true.
To measure individual harmonics at F between say 2kHz and 10kHz, you
need **band pass** filter, not a notch or band stop filter.
Its Q should be at least 50 for all F and the response when tuned to any
F of a constant amplitude input signal it must give equal output
voltages. I built such a unit using 3 opamps and a couple of overlapping
RC feedback networks including one pot which allows the Fo to be tuned
for maximum amplitude at harmonics selected. If you have such a filter
tuned to say 3kHz, then with Q of 50 the pass band is 60Hz wide between
the two -3dB poles. 2kHz will be 20dB down or more, and usually
measurements of 2,3,4,5,6,7,8,9H can be made without too much
interference between different H.
Many PP amps will have low 2H, and you'll get mostly 3H, with 2H maybe
-15dB down below 3H so you won't the 2H.
You can never take the spectra discovered for granted, and amps reveal
surprise results. However if whatever you measure is below 0.01%,
it does not matter because it will always be inaudible.
Usually, if THD is low, IMD will also be low. Where you have equal input
voltages of 3kHz and 5kHz, IMD products at 2kHz and 8kHz are formed
and these can be seen with the passband filter I have described. They
must indeed be IMD products because 2kHz and 8 kHz cannot be harmonic
products of 3kHz or 8kHz because the first harmonics above 3 and 8kHz
are 6kHz and 16kHz. Other second order IMD will be so low to not be
worth worrying about.
Most IMD tests were done using 4V of 80Hz input and 1V of 5kHz which
means you filter the output to remove 80Hz and 5kHz, and look for IMD
products of 4,920Hz and 5,080Hz. Its easier to leave the 5kHz visible,
and you'll measure the amount of amplitude modulation produced by the
presence of the 80Hz or other LF signal which can be any LF, as long as
you can filter it away while measuring the AM of the 5 kHz.
Thus high Q filters are not required for measuring total IMD.
RDH has more that's worth reading.
>
> As for pictures, the device I have bought is an HP 3581A Wave Meter - it
> is in effect a spectrum analyser but not with a PC interface for
> capturing nice pictures. You can connect it to a scope but as its scan
> rate is of the order of seconds you wont see much on a scope unless it
> is a storage type and mine isn't - it will interface directly to a pen
> plotter though!!!! I have seen a suggestion of using it with a USB data
> capture device but one of these costs more than I paid for the HP ;-) so
> for the present it will just have to be done by hand.
>
> OTOH a cheap PC interface type scope might do the trick.
>
> > Most 6CG7s that I have evaluated have similar THD
> > values, and yet in comparison tests, Westinghouse
> > and Telefunken are usually picked out as sounding
> > the best. Perhaps THD does not tell us the full story.
> >
>
> I am sure it does not. It is a start and the spectral shape of the
> harmonics is the second step. After that it is looking at
> intermodulation distortion which I can also do on the HP.
I've often measured tube preamp THD < 0.01% for the highest signals used
during normal operation.
If 2.83Vrms makes a watt into 8 ohms, then 0.01% THD is 0.283mV, and
with my speakers, 88dB/W/M, this is utterly inaudible. And it is usually
swamped by power amp THD/IMD at a watt, and the speaker THD/IMD.
RDH has a lot to say about the threshold of audibly detectable levels of
THD.
Yet we hear differences between brands of the same tube type number used
in preamps. Maybe its subtle microphonic effects.
But these effects could easily be more sound colouring than THD.
Patrick Turner.
>
> Cheers
>
> ian
Ian Bell
> On Tue, 27 Jan 2009 10:05:58 +0000, Ian Bell <ruffr...@yahoo.com>
>
I made a loop back lead so output was connected to input. Then I ran the
calibrate utility and it said there was insufficient gain and asked me
to alter the input gain. Unfortunately Windows Bloody Vista has no such
function. If you cannot get past this stage the program refuses to do
anything.
> Maybe they require sound blaster comparability. I don't recall, off
> hand, because I've got them on an old notebook running win98 and never
> really used them past seeing they 'worked' because I have a 'real'
> dual trace scope anyway.
>
>> No I was thinking more of those that plug into a usb port and have some
>> external = decent electronics.
>
> Sure. I was just trying to be 'cheap' ;) Especially since, if I
> gathered the setup correctly, all you need it for is display.
>
Pretty much and capture too of course.
Cheers
ian
>> Cheers
>>
>> Ian
Ian Bell
>
> Ian Bell wrote:
>> Iain Churches wrote:
>>> "Ian Bell" <ruffr...@yahoo.com> wrote in message
>>> news:gktetl$dka$1...@localhost.localdomain...
>>>> I have written up the work I did on investigating distortion in a 6SN7 mu
>>>> follower and posted it at my website. You can read it here:
>>>>
>>>> http://www.ianbell.ukfsn.org/data/mufollowerdistortion.pdf
>>>>
>>> Ian. Excellent paper.
>>>
>>> You mentioned that you had, or were in the process
>>> of acquiring, a HP spectrum analyser to examine the
>>> differences between the distortion profile of the
>>> different valves/tubes that you had tested.
>>>
>>> Have you done this analysis yet? Some pics would be of
>>> interest.
>>>
>> Not yet - I am at present struggling to get a twin T notch filter
>> working properly so I can measure the individual harmonics. However, I
>> can say from some initial tests without the twin T that at 20V rms the
>> 2H level is close to -50dB, the 3H seems to be around -75dB and the
>> third is below what my instrument will measure. So the contention that
>> it is 'mainly second harmonic' would seem to be true.
>
> To measure individual harmonics at F between say 2kHz and 10kHz, you
> need **band pass** filter, not a notch or band stop filter.
>
Yes, that is what the wavemeter does. It has selectable bandwidths of 3,
10,30,100 and 300Hz. It is tunable so I use it to look at each harmonic
in turn. The notch filter simply reduces the fundamental so I can turn
up the gain on the wavemeter and measure harmonics at very low levels.
Cheers
Ian
bigwig
> > wrote:
>
> >> flipper wrote:
> >>> On Mon, 26 Jan 2009 18:28:38 +0000, Ian Bell <ruffreco...@yahoo.com>
> >>> wrote:
>
> >>>> Iain Churches wrote:
> >>>>> "Ian Bell" <ruffreco...@yahoo.com> wrote in message
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
What program were you using? My laptop runs Vista as standard and its
not that bad or good. I had my friend put XP on the partition, it
works great except that it thinks the audio bus is being used by a
modem;-( Mine uses a crappy 945 chipset and I think this is the
problem. I dont really see them bringing out any new drivers soon or
ever. So basically any audio stuff I have tried on my laptop have been
a pain and or impossible to use.
Matt.
Ian Bell
I tried two programs neither of which I could get to work. One was
Rightmark Audio Analyser and the other was True RTA.
Cheers
Ian
bigwig
Thanks Ian,
I will try them but I am not holding any hopes for my laptop, its 18
months old now and it was middle of the line when new.
Matt.
Patrick Turner
There are also notch filters based on the wien bridge RC network.
Many ways to skin the cat.
Patrick Turner.
Ian Bell
It is a Samsung R700 only a few moths old
and did you check the manufacturer's site for XP
> drivers?
No I did not
Windows doesn't have 'everything' built in, you know.
>
Really., I am used to Linux where it is ;-)
Cheers
Ian
>> Matt.
Ian Bell
> there's the possibility of getting drivers for your on-board sound but
> on-board sound isn't all that good anyway so you might want to get a
> 'good' USB sound card (like, say, maybe M-Audio), which removes the
> driver problem.
>
> A USB card is also transportable to a new system, should you later
> upgrade.
That sounds like a good idea - might also work on Linux. Can you
recommend any?
Cheers
Ian
>
>> Matt.
Ian Bell
> On Tue, 27 Jan 2009 18:19:29 +0000, Ian Bell <ruffr...@yahoo.com>
> change everything for maximum confusion," it's not like XP, or any
> other flavor of Windows.
>
> If you have the sound ICON in your system tray right click and select
> input DEVICES, not the (near useless) "sound mixer." Then select the
> 'device' (I.E. line input) push properties and tab to levels. Advanced
> lets you chose the resolution and sample rate
>
Ah, typically obscure. I have managed to increase the mic input gain by
10dB. Hopefully the change will last aftger a power down. I'll recheck
both programs now.
Thanks for the help.
Cheers
Ian
> You can also get to it from "sounds" in Control Panel "Classic View"
> (my preferred presentation) or, in the designed for maximum confusion
> 'normal' (Home) setting, "Hardware and Sound," then "Sound," and then
> pick "Manage Devices" instead of what most sane people would pick
> "Adjust System Volume."
>
>> If you cannot get past this stage the program refuses to do
>> anything.
>>
>>
>>> Maybe they require sound blaster comparability. I don't recall, off
>>> hand, because I've got them on an old notebook running win98 and never
>>> really used them past seeing they 'worked' because I have a 'real'
>>> dual trace scope anyway.
>>>
>>>> No I was thinking more of those that plug into a usb port and have some
>>>> external = decent electronics.
>>> Sure. I was just trying to be 'cheap' ;) Especially since, if I
>>> gathered the setup correctly, all you need it for is display.
>>>
>> Pretty much and capture too of course.
>
> Here's a 'free' (for non commercial use) one. Got no idea how well it
> works. I just found it on a web search.
>
> http://zeitnitz.de/Christian/Scope/Scope_en.html
>
>
>> Cheers
>>
>> ian
>>>> Cheers
>>>>
>>>> Ian
Ian Bell
> On Wed, 28 Jan 2009 10:32:24 +0000, Ian Bell <ruffr...@yahoo.com>
> M-Audio Delta 66.
>
> That's PCI but it was too good a deal to pass up.
>
> Btw, it has Vista drivers, both 32 and 64 bit. It's the USB version
> that's missing the 64 bit drivers.
I have just come across the Sweex External Sound Card which seems to
have a plethora of inputs and outputs and apparently uses the C-Media
chip set, whatever that is. Is it any good??
|Cheers
Ian
>
>> Cheers
>>
>> Ian
>>>> Matt.