What is the bass difference with these different cab volumes?
- By djn
- Full Range
- 92 Replies
Hi all. I am building a new set of full range speakers and I'd like to get your thinking on using 4cu ft, 5cu ft, and 6.5cu ft cabinets as shown in the picture below. How obvious will the different roll-offs be?
Seeking user experience on Hybrid SRPP
- By GregH2
- Tubes / Valves
- 7 Replies
Hi All,
I've been reading about Ale's hybrid mu follower on the Bartola Valves website with interest. I'm sure it works very well, but it's complex enough that I would probably prefer to go all tube.
I'd like to try something a bit simpler and have a bunch of DN2540's in my junk box. Merlin Blencowe discusses a hybrid SRPP/mu follower similar to the one below in his tube preamp book, and I think it might be just the ticket. BTW I cannot recommend his book enough, it is up there with the best, a great read.
I'd be very interested to hear from anyone with experience using a circuit similar to that shown below, particularly with respect to distortion, sound and performance at high frequency. In simulation it appears pretty decent in the audio band at least, particularly with the 6SN7 below running at reasonable current.
Appreciate your thoughts.
Greg
Seek
I've been reading about Ale's hybrid mu follower on the Bartola Valves website with interest. I'm sure it works very well, but it's complex enough that I would probably prefer to go all tube.
I'd like to try something a bit simpler and have a bunch of DN2540's in my junk box. Merlin Blencowe discusses a hybrid SRPP/mu follower similar to the one below in his tube preamp book, and I think it might be just the ticket. BTW I cannot recommend his book enough, it is up there with the best, a great read.
I'd be very interested to hear from anyone with experience using a circuit similar to that shown below, particularly with respect to distortion, sound and performance at high frequency. In simulation it appears pretty decent in the audio band at least, particularly with the 6SN7 below running at reasonable current.
Appreciate your thoughts.
Greg
FS: Tektronix Bench PSU and Function Generator - PS280 and CFG280
- By luvdunhill
- Swap Meet
- 9 Replies
Hi! Both are in great shape! $350 for the pair. Open to trades as well.
Sony CX20197
Hi everyone!
I am looking for some info on the above Sony IC-s. Unfortunately tehere is close to nothing can be found on the web. All I know, is that it is a dual opamp, with +/-15 supply voltage, GBW: 40 MHz, SR: 20V/uS ratings. The reason: It sounds damn good...
In a DAC output stage it "overperformed" almost every modern, well respected dual opamps I've tried as far as speed, dynamics, and liveliness is concerned.. (in my system, of course 😉) Sony used these in some better CD players, and audio processors in the 80's.
If anyone has some more info or experience with these, please share with us....
I am looking for some info on the above Sony IC-s. Unfortunately tehere is close to nothing can be found on the web. All I know, is that it is a dual opamp, with +/-15 supply voltage, GBW: 40 MHz, SR: 20V/uS ratings. The reason: It sounds damn good...
In a DAC output stage it "overperformed" almost every modern, well respected dual opamps I've tried as far as speed, dynamics, and liveliness is concerned.. (in my system, of course 😉) Sony used these in some better CD players, and audio processors in the 80's.If anyone has some more info or experience with these, please share with us....
Attachments
Another NAD 3240PE mystery
- By baldrick
- Solid State
- 3 Replies
I've had this 3240PE integrated on my bench for a while now.
The symptom is that it has high offset on the right channel. 36 volts. Wow.
Checking the rails, the high voltage rails appear to be correct - + 76V and -76V
The positive low voltage rail is screwy - at +60V. The negative voltage rail is correct at -43 V.
Thinking that it could be a leaky component from the high voltage side, I disconnected PTC1 and PTC2, which disconnects the +/- 76 V rails.
But the difference in the low voltage rails persists.
Now, the offset is way lower in the right channel at +6V but it also appears in the left channel with the high voltage rails disconnected.
Any ideas from the experts?
Schematic for reference:
The symptom is that it has high offset on the right channel. 36 volts. Wow.
Checking the rails, the high voltage rails appear to be correct - + 76V and -76V
The positive low voltage rail is screwy - at +60V. The negative voltage rail is correct at -43 V.
Thinking that it could be a leaky component from the high voltage side, I disconnected PTC1 and PTC2, which disconnects the +/- 76 V rails.
But the difference in the low voltage rails persists.
Now, the offset is way lower in the right channel at +6V but it also appears in the left channel with the high voltage rails disconnected.
Any ideas from the experts?
Schematic for reference:
Harman-Kardon citation eleven (preamp) hum and hiss! help
- By Jonas83
- Analog Line Level
- 4 Replies
Attachments
mod NAD C520 (I'll add spdif input)
- By hehe31
- Digital Source
- 3 Replies
Hi everyone 😉
I want to improve the sound quality of my computer:
I just have a old Fortissimo II sound card (whith a spdif output), linked to an NAD amp (2 cinch analogic link) and JMLab speakers.
I can't buy a better sound card or a nice dac, no money
But i have an old NAD C320 i don't use (the cd reader is tired and jump times to times). I want tu use the DAC there is inside (PCM1710U) whith my spdif output 🙂
This is the interesting part (from service manual)
We can see the cd driver (LC78621) connected to the dac with the 3 wires. The dac generate the clock and give it to the cd driver.
The Quartz for LC78621 is wired but there isnt the Quartz and capas (the clock come from the dac^^)
There is my project:
I add a CS8416 to decode spdif.
I remove the dac's quartz and use the clock from the 8416.
The 8416 can choose between 2 spdif input: 1 from the cd driver and 1 from outside (coax plug).
I add the quartz for the cd driver
I remove mute transistors (not in picture, just before stereo output), mute is controlled my an other chip.
I don't test this (waiting for 8416^^), but it's the 1st time i work with digital audio signals.
Do u think i forget something? will it work? 😀 (and sorry for bad english^^)
I want to improve the sound quality of my computer:
I just have a old Fortissimo II sound card (whith a spdif output), linked to an NAD amp (2 cinch analogic link) and JMLab speakers.
I can't buy a better sound card or a nice dac, no money
But i have an old NAD C320 i don't use (the cd reader is tired and jump times to times). I want tu use the DAC there is inside (PCM1710U) whith my spdif output 🙂
This is the interesting part (from service manual)
An externally hosted image should be here but it was not working when we last tested it.
We can see the cd driver (LC78621) connected to the dac with the 3 wires. The dac generate the clock and give it to the cd driver.
The Quartz for LC78621 is wired but there isnt the Quartz and capas (the clock come from the dac^^)
There is my project:
An externally hosted image should be here but it was not working when we last tested it.
I add a CS8416 to decode spdif.
I remove the dac's quartz and use the clock from the 8416.
The 8416 can choose between 2 spdif input: 1 from the cd driver and 1 from outside (coax plug).
I add the quartz for the cd driver
I remove mute transistors (not in picture, just before stereo output), mute is controlled my an other chip.
I don't test this (waiting for 8416^^), but it's the 1st time i work with digital audio signals.
Do u think i forget something? will it work? 😀 (and sorry for bad english^^)
-
Article
Are switched mode power supplies noisy?
- By abraxalito
- Abraxalito
- 0 Replies
If you believe Benchmark's marketing then the answer's a definite 'no' - https://benchmarkmedia.com/blogs/ap...audio-myth-switching-power-supplies-are-noisy
However if you read further down, they do admit that 'many switching supplies are noisy'. They put this down to older designs using lower switching frequencies and 'low cost' designs like USB chargers. So they recommend that switching supplies be optimized for audio applications.
Nowhere in that article is there any mention of common-mode noise. That could be because its not really an issue when the inputs of an amp are balanced (via XLRs) as they are in Benchmark's AHB2 amp, which is their exemplar of 'switching PSUs done right'. With balanced ins, pin1 (direct to chassis) on the XLR takes care of any 'leakage' current and so the conductors carrying audio (pins2 and 3) are unaffected. However if the inputs to an amp are unbalanced then there are only two conductors available to carry leakage (common-mode) currents, both of which are in the audio circuit. Since practically all equipment I have has only unbalanced ins/outs the issue of CM noise is a major concern to me.
Common-mode currents arise because the oscillator in the SMPSU is connected to the primary of the power transformer and so inherently capacitively couples to the secondary via transformer parasitics. Here's a technical treatment : https://www.eetimes.com/power-tip-47-tame-conducted-common-mode-emissions-in-isolated-switchers-part-1. CM currents are ultrasonic, they can be seen on FFTs which look over a wide enough bandwidth or where the noise floor is low enough in the audio band. For example Exasound characterize their DACs both with and without galvanic isolation on the USB input and show the difference this makes on the FFT within the audio band : https://www.exasound.com/portals/0/Images/e32-Measurements/exaSound-e32-noise-no-isolation-800.png. With USB isolation there's no 'grass' above ~-168dB : https://www.exasound.com/portals/0/Images/e32-Measurements/exaSound-e32-Noise-Floor-800.png. These two plots indicate there must be some CM->DM conversion taking place as CM (presumably coming from the PC as USB host) won't show up on a typical DM measurement.
Suppressing CM noise currents isn't very straightforward and the EETimes article points out why - they are sourced from a very high impedance. So high impedances are needed to make a dent in their magnitude. Ferrite beads (for example) are useless as their impedance typically tops out around 1kohm. The first line of defense against CM noise is a CM choke and a typical insertion loss plot looks like this :
The different lines represent different current ratings, the one with the highest loss has the lowest current rating. Notice above roughly 1MHz all these different current rating chokes behave about the same - their parasitic capacitance determines their insertion loss. They all have SRFs (self-resonant frequencies) between 100kHz and 700kHz, the frequency where their stray capacitance resonates with their inductance.
To improve the HF performance its a standard technique to segment the windings - with two segments on each side the insertion loss plot looks like this :
More segments are possible of course but I've not seen any commercial CM choke with more than two. These two plots are from Murata devices designed for power lines - signal line chokes with high insertion losses close to the audio band aren't so easy to find. However on signal lines, transformers can do a reasonable job of increasing the CM impedance.
Update :
The EEtimes article has a substantial number of images with broken links, here's a document which helps make up for the lack of schematics and waveforms : http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.123.2941&rep=rep1&type=pdf. Page 1-8 and onward are most relevant in the treatment of CM noise currents.
However if you read further down, they do admit that 'many switching supplies are noisy'. They put this down to older designs using lower switching frequencies and 'low cost' designs like USB chargers. So they recommend that switching supplies be optimized for audio applications.
Nowhere in that article is there any mention of common-mode noise. That could be because its not really an issue when the inputs of an amp are balanced (via XLRs) as they are in Benchmark's AHB2 amp, which is their exemplar of 'switching PSUs done right'. With balanced ins, pin1 (direct to chassis) on the XLR takes care of any 'leakage' current and so the conductors carrying audio (pins2 and 3) are unaffected. However if the inputs to an amp are unbalanced then there are only two conductors available to carry leakage (common-mode) currents, both of which are in the audio circuit. Since practically all equipment I have has only unbalanced ins/outs the issue of CM noise is a major concern to me.
Common-mode currents arise because the oscillator in the SMPSU is connected to the primary of the power transformer and so inherently capacitively couples to the secondary via transformer parasitics. Here's a technical treatment : https://www.eetimes.com/power-tip-47-tame-conducted-common-mode-emissions-in-isolated-switchers-part-1. CM currents are ultrasonic, they can be seen on FFTs which look over a wide enough bandwidth or where the noise floor is low enough in the audio band. For example Exasound characterize their DACs both with and without galvanic isolation on the USB input and show the difference this makes on the FFT within the audio band : https://www.exasound.com/portals/0/Images/e32-Measurements/exaSound-e32-noise-no-isolation-800.png. With USB isolation there's no 'grass' above ~-168dB : https://www.exasound.com/portals/0/Images/e32-Measurements/exaSound-e32-Noise-Floor-800.png. These two plots indicate there must be some CM->DM conversion taking place as CM (presumably coming from the PC as USB host) won't show up on a typical DM measurement.
Suppressing CM noise currents isn't very straightforward and the EETimes article points out why - they are sourced from a very high impedance. So high impedances are needed to make a dent in their magnitude. Ferrite beads (for example) are useless as their impedance typically tops out around 1kohm. The first line of defense against CM noise is a CM choke and a typical insertion loss plot looks like this :
The different lines represent different current ratings, the one with the highest loss has the lowest current rating. Notice above roughly 1MHz all these different current rating chokes behave about the same - their parasitic capacitance determines their insertion loss. They all have SRFs (self-resonant frequencies) between 100kHz and 700kHz, the frequency where their stray capacitance resonates with their inductance.
To improve the HF performance its a standard technique to segment the windings - with two segments on each side the insertion loss plot looks like this :
More segments are possible of course but I've not seen any commercial CM choke with more than two. These two plots are from Murata devices designed for power lines - signal line chokes with high insertion losses close to the audio band aren't so easy to find. However on signal lines, transformers can do a reasonable job of increasing the CM impedance.
Update :
The EEtimes article has a substantial number of images with broken links, here's a document which helps make up for the lack of schematics and waveforms : http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.123.2941&rep=rep1&type=pdf. Page 1-8 and onward are most relevant in the treatment of CM noise currents.
The Hilding horn
- Full Range
- 79 Replies
Actually i prefer 2-way speakers, like large lf drivers and large boxes.
But there is something very special with fr drivers, larger ones that can deliver real lf to are sparse, i havent heard any since Coral Beta 10 and Beta 8, these are unobtaiable today.
Stumbled on this tiny one when working on the quite large Experience Live cinema speaker project.
FaitalPRO - Professional Loudspeakers Made in Italy
So, what to do whit this one then?
Test it to find out how it sings.
Quick and dirty, glue it to one end of a large russian toiletpaper core.
Sound below a normal A awfull or nonexisting, but above that, really astonishing.
What do we do then?
Rear loaded horn? Why not!
Maybe like this?
But there is something very special with fr drivers, larger ones that can deliver real lf to are sparse, i havent heard any since Coral Beta 10 and Beta 8, these are unobtaiable today.
Stumbled on this tiny one when working on the quite large Experience Live cinema speaker project.
FaitalPRO - Professional Loudspeakers Made in Italy
So, what to do whit this one then?
Test it to find out how it sings.
Quick and dirty, glue it to one end of a large russian toiletpaper core.
Sound below a normal A awfull or nonexisting, but above that, really astonishing.
What do we do then?
Rear loaded horn? Why not!
Maybe like this?
Are these Capacitors Polarized?
- By bedrock602
- Solid State
- 9 Replies
I bought a bunch of POLARIZED caps of different values for my Sherwood restoration, they all have a + sign on one end, these 100 uF caps do not but instead have stripe down one side. Do the arrows indicate the negative or positive end?
LC filter (Capasitor)
Which 0.47 uF 100 Volt capacitor would you choose for the LC filter at a kl. D amplifier?
Can an ordinary Wima capacitor as in the picture be used there?
Thanks
Can an ordinary Wima capacitor as in the picture be used there?
Thanks
Where to position transformers for line stage build
- By SoaDMTGguy
- Tubes / Valves
- 0 Replies
Attachments
Opinions for GNDs bettwen Pins of LM3886 ( Pin 7,9,10,11 )
closed, because of no Feedback an Interest, could be that I boring you with this.
