Danley BC Subs Revisited
- Subwoofers
- 14 Replies
Someone on Facebook was asking about the Danley BC subs, and I personally think that the concept is fairly straightforward, and it's come up on FB a few times so I thought I'd do a quick "brain dump" here.
On Facebook, I (sorta) joked that: "'Boundary Coupled' is just marketing speak for "the baffle is really big.'"
So let's elaborate on this a little bit:
First off, the primary reason that radiator has higher output on axis when it's on a horn or waveguide is because the waveguide takes the output from a radiator and constrains it into a narrower beam.
This is no different that now a light bulb can barely illuminate a room, but a ten watt diode laser can cut through wood:
A diode laser takes it's energy and focuses it in a point, a woofer in a baffle that is sufficiently small will radiate in all directions (spherical) and if you put a radiator onto a big flat baffle, the baffle itself will keep the energy from radiating backwards.
Next thing that we do is figure out "What is that frequency?"
Danley BC-218 measures five feed wide by five feet tall by 2.5 feet deep. That's a baffle face of 152cm x 152cm. The exit of the BC218 is NOT in the center of it's baffle, and that has an impact, but describing that effect is beyond the level of this discussion. (You can sim it in ABEC or VituixCad.)
This next thing is pretty important I think: Keep in mind that the radiation from the radiator has to wrap around the enclosure before it can radiate in 360 degrees. If we just looked at the front of the baffle, we could constrain radiation down to 224Hz. This is because the front of the baffle is 152x152cm and 224Hz is 152cm long.
BUT - once we include the sides of the enclosure, we're looking at radiation control down to 112Hz. That's because the additional thirty inches, on each side, increases the baffle size to 120 inches wide.
Now at his point you're probably wondering "what's the point of a subwoofer that "controls radiation" down to 112Hz?"
The answer to that, for the Danley BC Subs and Danley's B-DEAP subs that he made at Sound Physics Labs, is that they're really designed to be arrayed. That's why I didn't do a deep dive into the mouth location. The subs don't make a lot of sense when used in singles. Add a second BC-218 sub and you're controlling radiation down to 56Hz, easy.
The next step in this, is that once you place the sub on the floor, the floor itself increases the on-axis efficiency. This ALSO gets tricky, because the floor isn't a perfect mirror of the loudspeaker. But chances are good that you will be putting your speaker or subwoofer on a floor, so it stands to reason that you would want to leverage it to improve the performance of your speaker.
On a side note, if it's not obvious, you could avoid a lot of this by just cramming a subwoofer into a corner. But BC subs arguably are best outside or in a big room, where that huge baffle can constrain radiation. I think this is particularly important for festivals where you don't want the subwoofer to "bleed" into the next stage over, or the stage behind it.
I think it's also useful for clubs and the like, because it's controlled radiation reduces energy radiated into adjacent buildings.
On Facebook, I (sorta) joked that: "'Boundary Coupled' is just marketing speak for "the baffle is really big.'"
So let's elaborate on this a little bit:
First off, the primary reason that radiator has higher output on axis when it's on a horn or waveguide is because the waveguide takes the output from a radiator and constrains it into a narrower beam.
This is no different that now a light bulb can barely illuminate a room, but a ten watt diode laser can cut through wood:
A diode laser takes it's energy and focuses it in a point, a woofer in a baffle that is sufficiently small will radiate in all directions (spherical) and if you put a radiator onto a big flat baffle, the baffle itself will keep the energy from radiating backwards.
Next thing that we do is figure out "What is that frequency?"
Danley BC-218 measures five feed wide by five feet tall by 2.5 feet deep. That's a baffle face of 152cm x 152cm. The exit of the BC218 is NOT in the center of it's baffle, and that has an impact, but describing that effect is beyond the level of this discussion. (You can sim it in ABEC or VituixCad.)
This next thing is pretty important I think: Keep in mind that the radiation from the radiator has to wrap around the enclosure before it can radiate in 360 degrees. If we just looked at the front of the baffle, we could constrain radiation down to 224Hz. This is because the front of the baffle is 152x152cm and 224Hz is 152cm long.
BUT - once we include the sides of the enclosure, we're looking at radiation control down to 112Hz. That's because the additional thirty inches, on each side, increases the baffle size to 120 inches wide.
Now at his point you're probably wondering "what's the point of a subwoofer that "controls radiation" down to 112Hz?"
The answer to that, for the Danley BC Subs and Danley's B-DEAP subs that he made at Sound Physics Labs, is that they're really designed to be arrayed. That's why I didn't do a deep dive into the mouth location. The subs don't make a lot of sense when used in singles. Add a second BC-218 sub and you're controlling radiation down to 56Hz, easy.
The next step in this, is that once you place the sub on the floor, the floor itself increases the on-axis efficiency. This ALSO gets tricky, because the floor isn't a perfect mirror of the loudspeaker. But chances are good that you will be putting your speaker or subwoofer on a floor, so it stands to reason that you would want to leverage it to improve the performance of your speaker.
On a side note, if it's not obvious, you could avoid a lot of this by just cramming a subwoofer into a corner. But BC subs arguably are best outside or in a big room, where that huge baffle can constrain radiation. I think this is particularly important for festivals where you don't want the subwoofer to "bleed" into the next stage over, or the stage behind it.
I think it's also useful for clubs and the like, because it's controlled radiation reduces energy radiated into adjacent buildings.
Power Amplifier Board local power rail bypass question
- By radio_free
- Solid State
- 3 Replies
Attachments
Boston Acoustics PV800 Sub Bash Amp Needs Help
- By DavidKS
- Subwoofers
- 3 Replies
Hello All,
Got a Boston Acoustics PV800 Subwoofer needing some help. I really like this sub and would like to save it if possible. I know that it is a BASH amp and that I have very limited knowledge and skills. I probably know the names of about 25% of the components involved and I know a guy who can solder pretty well. I'll give a description of it's behavior and what I know and and have done so far. Hopefully someone here sees or reads something here for a fix.
Plugging the sub to power usually results is a dim (about 20% of expected brightness) LED indicator. This is regardless of the subs power switch setting (on, auto, off). If the switch is "off or auto" you get dim red, if the switch in "on", you get dim green. This sometimes give a faint, shrill squealing type sound from the sub. When powering on to a dim LED indicator you always get 160V from the power supply board (see circled areas in pics). . . the board that receives the 160V will then always output ~12V (see circled area in pics)
When the sub gets plugged in and works, of course the LED behaves as it should. The one other obvious difference is that the board that was outputting ~12V is now outputting ~30V
When the sub doing the dim LED behavior, I can jump start the sub as follows. For about 4 seconds, I run a hair dryer on the left half of the BASH labeled board then plug in the power cable. Sub immediately comes to life. If I now leave the properly working sub plugged in overnight and everything get warmed up, unplug the sub then plug it back in. . . I get the dim LED fail again.
There is only one repair that I have done (and it didn't change the behavior). In one of the circled areas in the pics, there were two transistors that had their faces blown off, I had them replaced.
Thoughts anyone?
Got a Boston Acoustics PV800 Subwoofer needing some help. I really like this sub and would like to save it if possible. I know that it is a BASH amp and that I have very limited knowledge and skills. I probably know the names of about 25% of the components involved and I know a guy who can solder pretty well. I'll give a description of it's behavior and what I know and and have done so far. Hopefully someone here sees or reads something here for a fix.
Plugging the sub to power usually results is a dim (about 20% of expected brightness) LED indicator. This is regardless of the subs power switch setting (on, auto, off). If the switch is "off or auto" you get dim red, if the switch in "on", you get dim green. This sometimes give a faint, shrill squealing type sound from the sub. When powering on to a dim LED indicator you always get 160V from the power supply board (see circled areas in pics). . . the board that receives the 160V will then always output ~12V (see circled area in pics)
When the sub gets plugged in and works, of course the LED behaves as it should. The one other obvious difference is that the board that was outputting ~12V is now outputting ~30V
When the sub doing the dim LED behavior, I can jump start the sub as follows. For about 4 seconds, I run a hair dryer on the left half of the BASH labeled board then plug in the power cable. Sub immediately comes to life. If I now leave the properly working sub plugged in overnight and everything get warmed up, unplug the sub then plug it back in. . . I get the dim LED fail again.
There is only one repair that I have done (and it didn't change the behavior). In one of the circled areas in the pics, there were two transistors that had their faces blown off, I had them replaced.
Thoughts anyone?
My version of an Ultrasonic Record Cleaner
- By bbftx
- Analogue Source
- 2336 Replies
I've had a VPI HW-17 record cleaner for some time, but have always wondered if there was a way that could deliver better cleaning results along with less contact with the vinyl . So, after reading threads here and elsewhere about using ultrasonic cleaners to get the dirt off of vinyl, I thought I'd rig up my own unit.
I started with an ultrasonic cleaner that uses 60 KHz transducers. It was a little harder to find and a little more expensive than the typical 40KHz Chinese-made units, but the higher frequencies theoretically do a better job at cleaning the very small grooves of a record and there is less risk of damaging the vinyl from the cavitation. Those two points are a big advantage of 60khz units over 40khz units.
To rotate the records, I wanted to minimize motion in the cleaning solution. My target was a 4 minute cleaning time for the vinyl surface. Given that about 1/3 of the record is submerged in the solution at any moment, the math told me to find a 5 revolution per HOUR synchronous motor. Synchron makes such motors in almost any rph or rpm you could want. The 5rph motor yields a 12 minute rotation time. My plan is 1 rotation = 1 cleaning cycle.
I fashioned a spindle out of 9/32 W1 drill rod. It was was easy to machine a 1/8" diameter hole in one end of the spindle on my lathe to fit over the motor shaft (1/8" diameter).
The motor and shaft are mounted in place using an electrical connector box and conduit. The arm is mounted to the ultrasonic unit using L-brackets and pipe straps. The setup allows the motor and spindle assembly to be rotated up to load records, and then rotated down into the bath.
My spacers are 4" diameter, 1/2" thick cork rounds. [Oct 2012 note: I have since found different spacers, which are much better: I've ordered these from the UK: 110mm by 105mm tapered cork stoppers - they cover the record label completely and very little of the lead out groove. They are just a touch over 1" thick, which is optimal spacing.
No.37 Natural Cork Stopper 110mm from Just Cork No. 37 Large]
[Dec 2012 Note: I added a sintered bronze bearing and a bearing housing to support the weight of the spindle, records and spacers, and eliminate the bending moment on the motor shaft.]
I'll report back after I clean and play some vinyl. My first batches will use distilled water and isopropyl alcohol at about 7 to 1 [Sep 2012 note: I've since gone to a much lower concentration of isopropyl, about 50 to 1] , with a few drops of Kodak PhotoFlo. This solution, combined with the very slow rotation, will allow the liquid to drain off the vinyl surface very easily.
The cleaner can still be used for any items you'd normally put in an ultrasonic unit. It does a great job on some fairly intricate gold jewelry I've cleaned.
Photos below. Questions and comments welcome.
[Feb 2013 Note: I have built a second, sturdier design using a metal frame and hinge assembly that fits over the top of the Ultrasonic cleaner. Here is a direct link to the description later in this thread:
Version 2 of BB's URC
And here's a direct link to the post with the parts list for Version 2:
BB's URC Version 2 Parts List ]
Feb 2015 Note: I've built a 3rd version, designed to be assembled with fewer tools and be more adaptable to different cleaners. Description and pics for Version 3 start here:
BB's URC Version 3
Parts list for Version 3 reposted here: BB's Version 3 Parts List
Happy building.
Cheers,
BB
View attachment 297136View attachment 297137View attachment 297139View attachment 297140
View attachment 297141View attachment 297142
I started with an ultrasonic cleaner that uses 60 KHz transducers. It was a little harder to find and a little more expensive than the typical 40KHz Chinese-made units, but the higher frequencies theoretically do a better job at cleaning the very small grooves of a record and there is less risk of damaging the vinyl from the cavitation. Those two points are a big advantage of 60khz units over 40khz units.
To rotate the records, I wanted to minimize motion in the cleaning solution. My target was a 4 minute cleaning time for the vinyl surface. Given that about 1/3 of the record is submerged in the solution at any moment, the math told me to find a 5 revolution per HOUR synchronous motor. Synchron makes such motors in almost any rph or rpm you could want. The 5rph motor yields a 12 minute rotation time. My plan is 1 rotation = 1 cleaning cycle.
I fashioned a spindle out of 9/32 W1 drill rod. It was was easy to machine a 1/8" diameter hole in one end of the spindle on my lathe to fit over the motor shaft (1/8" diameter).
The motor and shaft are mounted in place using an electrical connector box and conduit. The arm is mounted to the ultrasonic unit using L-brackets and pipe straps. The setup allows the motor and spindle assembly to be rotated up to load records, and then rotated down into the bath.
My spacers are 4" diameter, 1/2" thick cork rounds. [Oct 2012 note: I have since found different spacers, which are much better: I've ordered these from the UK: 110mm by 105mm tapered cork stoppers - they cover the record label completely and very little of the lead out groove. They are just a touch over 1" thick, which is optimal spacing.
No.37 Natural Cork Stopper 110mm from Just Cork No. 37 Large]
[Dec 2012 Note: I added a sintered bronze bearing and a bearing housing to support the weight of the spindle, records and spacers, and eliminate the bending moment on the motor shaft.]
I'll report back after I clean and play some vinyl. My first batches will use distilled water and isopropyl alcohol at about 7 to 1 [Sep 2012 note: I've since gone to a much lower concentration of isopropyl, about 50 to 1] , with a few drops of Kodak PhotoFlo. This solution, combined with the very slow rotation, will allow the liquid to drain off the vinyl surface very easily.
The cleaner can still be used for any items you'd normally put in an ultrasonic unit. It does a great job on some fairly intricate gold jewelry I've cleaned.
Photos below. Questions and comments welcome.
[Feb 2013 Note: I have built a second, sturdier design using a metal frame and hinge assembly that fits over the top of the Ultrasonic cleaner. Here is a direct link to the description later in this thread:
Version 2 of BB's URC
And here's a direct link to the post with the parts list for Version 2:
BB's URC Version 2 Parts List ]
Feb 2015 Note: I've built a 3rd version, designed to be assembled with fewer tools and be more adaptable to different cleaners. Description and pics for Version 3 start here:
BB's URC Version 3
Parts list for Version 3 reposted here: BB's Version 3 Parts List
Happy building.
Cheers,
BB
View attachment 297136View attachment 297137View attachment 297139View attachment 297140
View attachment 297141View attachment 297142
Cube Audio FC8 speaker build help
- Construction Tips
- 4 Replies
Hello everyone,
I want to build this (plan below) bass reflex cabinet for the Cube Audio FC8 driver. This is my first attempt and I have some questions.
1. Are there any acoustic downsides to screwing the back panel in place so access to the interior can be maintained ?
2. There is a label on the side elevation drawing which says "This section might be filled with sand". What are the pros and cons of doing so, and what would be the process for filling / removing the sand ?
3. I have an oak floor which is laid on concrete. What sort of speaker feet would be best ?
Thanks in advance for any help,
Mark
I want to build this (plan below) bass reflex cabinet for the Cube Audio FC8 driver. This is my first attempt and I have some questions.
1. Are there any acoustic downsides to screwing the back panel in place so access to the interior can be maintained ?
2. There is a label on the side elevation drawing which says "This section might be filled with sand". What are the pros and cons of doing so, and what would be the process for filling / removing the sand ?
3. I have an oak floor which is laid on concrete. What sort of speaker feet would be best ?
Thanks in advance for any help,
Mark
Thoughts on a unique OB setup
Login to view embedded media
Login to view embedded media
Front and rear coaxial 8"s (from JBL 328CT) on a sideless enclosure as shown- I'm currently running it as a front/back dipole (coaxes out of phase front and rear) but it's designed to allow for a "dipole/bipole" configuration where cancellation will be more like a pair of traditional open baffles firing front and rear. They are set up on top of subs rather than on the floor (as shown).
Dipole cancellation's pretty straightforward, either the "inside" of drivers cancel and the front and rear have an effective baffle width of the baffle width plus 1" (Added waveguide effective depth) plus 7.5" (1/2 the total system depth between baffles)
When run as "bipole dipole" effective baffle width is simply Baffle Width + .75 (1/2 of the 1.5" thick baffle) +1" (Added Waveguide effective depth)
I haven't had a chance to measure in the current setup, but I'm currently crossing at 140hz, which is probably an overly aggressive high-pass (could probably be lower), but I'd love to hear any thoughts people have on such a setup.
The coaxes are normally ceiling mounted with a shallow waveguide, my waveguide is somewhat improved, in that it closely tracks the cone profile and is slightly larger, deeper, and smoother than the JBL ceiling mount metal waveguide. This is important as the horn leverages the cone as the waveguide so that transition must be as smooth as possible.
I'd love to hear any thoughts- this is an experimenter system, regardless of the (rather ridiculous) effort required to create the waveguide. Naturally I have my own ideas for what might work in this highly configurable system, but I figure this is the best place for such conversations.
Login to view embedded media
Front and rear coaxial 8"s (from JBL 328CT) on a sideless enclosure as shown- I'm currently running it as a front/back dipole (coaxes out of phase front and rear) but it's designed to allow for a "dipole/bipole" configuration where cancellation will be more like a pair of traditional open baffles firing front and rear. They are set up on top of subs rather than on the floor (as shown).
Dipole cancellation's pretty straightforward, either the "inside" of drivers cancel and the front and rear have an effective baffle width of the baffle width plus 1" (Added waveguide effective depth) plus 7.5" (1/2 the total system depth between baffles)
When run as "bipole dipole" effective baffle width is simply Baffle Width + .75 (1/2 of the 1.5" thick baffle) +1" (Added Waveguide effective depth)
I haven't had a chance to measure in the current setup, but I'm currently crossing at 140hz, which is probably an overly aggressive high-pass (could probably be lower), but I'd love to hear any thoughts people have on such a setup.
The coaxes are normally ceiling mounted with a shallow waveguide, my waveguide is somewhat improved, in that it closely tracks the cone profile and is slightly larger, deeper, and smoother than the JBL ceiling mount metal waveguide. This is important as the horn leverages the cone as the waveguide so that transition must be as smooth as possible.
I'd love to hear any thoughts- this is an experimenter system, regardless of the (rather ridiculous) effort required to create the waveguide. Naturally I have my own ideas for what might work in this highly configurable system, but I figure this is the best place for such conversations.
6E5P Microphony
- Tubes / Valves
- 25 Replies
I've been working on a single ended parafeed headphone amp that I've had for the better part of the past decade. Every few years I take it apart to try something new. Most recently, I converted it from 6S45Ps to 6E5Ps and can't seem to dial these new tubes in.
I've attached the schematic of the amp section and a photo of the amp. The power supply uses a big SumR toroid followed by a 6BY5 rectifier and LC filter (5H + 420uF MKP). The raw supply is shunt regulated. The regulator is a simple IXYS DMOS CCS with no cascode set to 120mA. The shunt leg is a high voltage MOSFET with 3 0C3 glow tubes spanning from the drain to gate to generate a 330V regulated B+ supply. All tubes are heated with AC, with the rectifier tube and signal tube on different windings.
The amp section is quite simple. The 6E5P has about 4V on the cathode and is biased to 30mA with a CCS on the plate. There's a 2k grid stopper, 10R on each cathode pin, 100R on g2, and I've experimented with plate stoppers but ended up taking them out. The tubes are on teflon sockets which mount directly to a small PCB, and the stoppers are 0603 thin film resistors that are physically no more than 2mm from their respective pins.
The issue I'm hearing is really strange. Certain notes seem to excite a microphonic resonance in the tubes right around 3.5k. As the volume is increased, the intensity and duration of the ringing inreases, too. Hi-hats just sound miserable.
I had a couple of hypotheses: either the tubes were oscillating at RF, making them more prone to microphonic ringing, or there's some junk sneaking in through the power supply. Here's a partial list of things I tried.
And here's the noise floor, with input transformers, taken before running the FR sweep. Note the peak at 3.5k and the rise in the noise floor centered around 7k. This measurement was also taken with 20k grid stoppers, and the rise at 7k was much higher with 2k in place.
I know the tube is well liked here. Any thougts on how I can get them to sound good?
I've attached the schematic of the amp section and a photo of the amp. The power supply uses a big SumR toroid followed by a 6BY5 rectifier and LC filter (5H + 420uF MKP). The raw supply is shunt regulated. The regulator is a simple IXYS DMOS CCS with no cascode set to 120mA. The shunt leg is a high voltage MOSFET with 3 0C3 glow tubes spanning from the drain to gate to generate a 330V regulated B+ supply. All tubes are heated with AC, with the rectifier tube and signal tube on different windings.
The amp section is quite simple. The 6E5P has about 4V on the cathode and is biased to 30mA with a CCS on the plate. There's a 2k grid stopper, 10R on each cathode pin, 100R on g2, and I've experimented with plate stoppers but ended up taking them out. The tubes are on teflon sockets which mount directly to a small PCB, and the stoppers are 0603 thin film resistors that are physically no more than 2mm from their respective pins.
The issue I'm hearing is really strange. Certain notes seem to excite a microphonic resonance in the tubes right around 3.5k. As the volume is increased, the intensity and duration of the ringing inreases, too. Hi-hats just sound miserable.
I had a couple of hypotheses: either the tubes were oscillating at RF, making them more prone to microphonic ringing, or there's some junk sneaking in through the power supply. Here's a partial list of things I tried.
- Increasing all stoppers and adding plate stoppers. Bumping up the grid stopper to 20K helped just a bit, but now I don't manage 20kHz bandwidth.
- Converting the power supply to an LCRCRC, or a cLCRCRC where the first C is about 100nF. Currently, the three caps are in parallel with no Rs, and no small input cap.
- Elevating the 6E5P heaters to 50V (surprisingly, didn't impact 60Hz noise at all)
- Starving the 6E5P heaters to 6V to reduce gm
- Redoing all the ground wiring
- Changing the bias current from 40mA to 30mA per tube to reduce gm
- Adding input transformers
- Adding an EMI filter on the RCA input connectors
- Adding an EMI filter on the IEC power connector
- Trying out 6 different 6E5Ps, two different manufacturer stamps with different date codes. These all rang within a few 100Hz of each other.
- Adding a ground loop breaker between the circuit ground and IEC earth
- Removing the power supply regulator entirely
- Measuring with the inputs shorted (gave slightly lower noise than with RCA cables)
- Switching between a standard parafeed connection (primary returning to ground) and a WE parafeed connection (primary returning to cathode)
And here's the noise floor, with input transformers, taken before running the FR sweep. Note the peak at 3.5k and the rise in the noise floor centered around 7k. This measurement was also taken with 20k grid stoppers, and the rise at 7k was much higher with 2k in place.
I know the tube is well liked here. Any thougts on how I can get them to sound good?
Attachments
Can't connect to QCC3008
- By Horson
- Digital Line Level
- 19 Replies
I've got a couple of QCC3008 modules that I just can't connect to via SPI (I keep getting an 'error detecting chip type' message in the WIN1.0.167 version of PSTool) and I'm wondering if its because they have the later type bluetooth module on them rather than the older BTM308-C. My USB to SPI interface is working fine on the older modules (8630), I've tried connecting SPI_En directly to 1V8 and 3V3 via a resistor. I can't even change the firmware as Blueflash doesn't recognise the chip.
This is the older type
This is the later ones I've got.
I was just wondering if anybody had had success connecting to these later type modules as in the Youtube video series from Dariee, he uses the older type and I can't find anything out about the later modules.
Many thanks.
This is the older type
This is the later ones I've got.
I was just wondering if anybody had had success connecting to these later type modules as in the Youtube video series from Dariee, he uses the older type and I can't find anything out about the later modules.
Many thanks.
Old Samson RS12 PA Speakers with Hexagon-shaped Pole Mounts?
- By rayb70
- PA Systems
- 2 Replies
Hello, I have a pair of older RS12 PA Speakers from Samson. They are about 20 years old. The manual says they can "be stand mounted via their standard 1 3/8-inch speaker stand receptacles". I purchased Samson LS50P speaker stands which have standard 1 3/8" pole adapters, which are round, like a cylinder. The RS12 speakers have hexagon-shaped pole mount holes. The posts fit in the holes, but are tight and a bit difficult to disconnect. Here is a photo of the pole mounts:
Am I doing this correctly or are there different pole adapters for the hexagon-shaped holes? I looked and I see no mention of adapters like this, but maybe they are just too old?
I contacted Samson, but the answer I received seemed a bit lacking. They said "It must be very old. The new units are very different. I don't think you are doing anything wrong. It should be tight, but not too tight."
Does anyone know if this is just the way it is and that I am not doing anything wrong?
I appreciate any info. I'm just a hobbyist, but wanted to get this correct.
Thanks.
Am I doing this correctly or are there different pole adapters for the hexagon-shaped holes? I looked and I see no mention of adapters like this, but maybe they are just too old?
I contacted Samson, but the answer I received seemed a bit lacking. They said "It must be very old. The new units are very different. I don't think you are doing anything wrong. It should be tight, but not too tight."
Does anyone know if this is just the way it is and that I am not doing anything wrong?
I appreciate any info. I'm just a hobbyist, but wanted to get this correct.
Thanks.
For Sale Free Hook Up Wire Part I for pickup in San Diego area
Hey there, you know how it is, reorganizing and want to get rid of a LOT of wire and also how about some heat shrink for you.
Pickup in San Diego area- Miramar Road off the 15.
Most all the wire is silver-teflon MIL spec ranges from say 24-12 AWG.
The pictures are accurate but looking at them... there is more than you think in those spools and boxes.
This is FREE to whoever wants it, in support of your DIY efforts.
Just post here that you want some or all of it so I know to check my email, which is-
"john1in2" and "at symbol" yahoo.com (just don't want to put in an email link for harvesting).
Also if you are chatty- chat me up! I have other diy stuff that I could give away or sell- capacitors, chassis, etc... lets see what you are into and what you need as I have stopped building after filling up a room of equipment.
Box 01- some spools in here are copper but the bags are silver teflon (mostly)
Box 02
Spools 01, all MIL silver/teflon. the purple/white spool is very full.
Heat Shrink- I'll even throw in the heat gun for you. This is 1/4" red and 1/8 red and another 1/8 black non adhesive
Pickup in San Diego area- Miramar Road off the 15.
Most all the wire is silver-teflon MIL spec ranges from say 24-12 AWG.
The pictures are accurate but looking at them... there is more than you think in those spools and boxes.
This is FREE to whoever wants it, in support of your DIY efforts.
Just post here that you want some or all of it so I know to check my email, which is-
"john1in2" and "at symbol" yahoo.com (just don't want to put in an email link for harvesting).
Also if you are chatty- chat me up! I have other diy stuff that I could give away or sell- capacitors, chassis, etc... lets see what you are into and what you need as I have stopped building after filling up a room of equipment.
Box 01- some spools in here are copper but the bags are silver teflon (mostly)
Box 02
Spools 01, all MIL silver/teflon. the purple/white spool is very full.
Heat Shrink- I'll even throw in the heat gun for you. This is 1/4" red and 1/8 red and another 1/8 black non adhesive
For Sale PCB´s for Lunddahl SUTs
Needed the SUT´s for other project, so here´s a pair of PCB´s for most Lunddahl SUT´s.
They are from Emission Labs, and have a bunch of connection possibilities, such as Variable load, Zobel,
fixed load, fixed cap, links for serial or parallel connection a.o.
25 Euro with untracked free shipping inside EU. Rest of the world.... Ask.
PayPal fam. & friends only in danish currency = 185,00 DKr.
They are from Emission Labs, and have a bunch of connection possibilities, such as Variable load, Zobel,
fixed load, fixed cap, links for serial or parallel connection a.o.
25 Euro with untracked free shipping inside EU. Rest of the world.... Ask.
PayPal fam. & friends only in danish currency = 185,00 DKr.
The Runt - A nice little SE EL84 amp.
- By dubadub
- Tubes / Valves
- 6 Replies
Greetings, Friends. I wanted to share my progress on the little SE EL84 amp I've been playing with.
It's undergone a host of changes since my last update. I've installed a pair of 10w 3.5k OPTs, rewired the output tubes for Triode mode, and rewired the driver stage to mirror @Suncalc 's Marblewood Amp. In fact, I seem to have arrived at an EL84 version of that design. Per the EL84 datasheet, a pair of EL84 wired in triode with a 270ohm Kr will pull 2x 36mA = 72mA. Trying to be frugal as the PT only is rated for 104mA.
And the power supply
obligatory gut shot - Large Orange Caps!
As expected, the smaller OPTs deliver less bass than the 15W, but the amp has such a delightful clarity through the upper range that I don't miss it. I had an afternoon of Joe Pass records that really made me fall in love with the amp. Rewiring the driver stage to the "Universal 4S Preamp" made a huge improvement, thanks Matt for posting such wonderful designs!
It's undergone a host of changes since my last update. I've installed a pair of 10w 3.5k OPTs, rewired the output tubes for Triode mode, and rewired the driver stage to mirror @Suncalc 's Marblewood Amp. In fact, I seem to have arrived at an EL84 version of that design. Per the EL84 datasheet, a pair of EL84 wired in triode with a 270ohm Kr will pull 2x 36mA = 72mA. Trying to be frugal as the PT only is rated for 104mA.
And the power supply
obligatory gut shot - Large Orange Caps!
As expected, the smaller OPTs deliver less bass than the 15W, but the amp has such a delightful clarity through the upper range that I don't miss it. I had an afternoon of Joe Pass records that really made me fall in love with the amp. Rewiring the driver stage to the "Universal 4S Preamp" made a huge improvement, thanks Matt for posting such wonderful designs!
Attachments
For Sale JLH Phono Shunt feedback PCB's (new old stock)
- By jamesfeline
- Swap Meet
- 2 Replies
Hello
I now have some surplus JLH phono shunt feedback PCB's for sale (new old stock) that I purchased originally some time ago
asking £20 each plus postage ( 4 boards are available) I am UK based and would like payment by PayPal
happy to get a postage quote before I post please note one PCB will make a stereo preamp .. plus will provide construction manual via email if needed.
I now have some surplus JLH phono shunt feedback PCB's for sale (new old stock) that I purchased originally some time ago
asking £20 each plus postage ( 4 boards are available) I am UK based and would like payment by PayPal
happy to get a postage quote before I post please note one PCB will make a stereo preamp .. plus will provide construction manual via email if needed.
Anyone ever done a fixed tone stack voicing circuit?
- By jjasniew
- Instruments and Amps
- 0 Replies
In a Mesa Maverick, one channel has a fixed tone stack, of the usual Fender design. The other channel has B,M,T panel controls in a similar stack topology.
Anyone ever done this as a basic "voicing" design ingredient?
Perhaps imparts a generic eq similar to this;
Anyone ever done this as a basic "voicing" design ingredient?
Perhaps imparts a generic eq similar to this;
About beta-enhancing emitter-follower buffer between the input stage and the VAS
- By gaetan8888
- Solid State
- 39 Replies
Attachments
For Sale UK: Troels Gravesen Speakers ScanSpeak Discovery-3WC-MkII in Baltic Birch Enclosure
Troels Gravesen Speakers ScanSpeak Discovery-3WC-mkII in a baltic birch multiply enclosure (surface so far unfinished).
Detailed info about the speaker available on Troel's hompage troelsgravesen.dk
GBP 599 (for the pair) for self-collectors in the UK (or plus fuel cost if I deliver and you don't live too far away from Milton Keynes).
These speakers wwere built from a kit from Jantzen Audio in Denmark (level 2 crossover parts).
The enclosure has been built from baltic birch 18mm. The surface is so far unfinished and the buyer can decide if they just want to put lacqeur on top or a veneer.
Comes with the original instructions from Troels.
Scanspeak drivers are
D2608/913000 tweeter
15W/8434G00 mid range
22W/8534G00 woofer
The crossover is built from parts of that Jantzen kit. The upgraded binding posts are the components that did not come with the kit.
I also have applied L-pads for the mid and high range, but you can unplug those if you like the original sound better.
because of the weight and fragile nature I cannot ship these speakers via post.
Collection in Milton Keynes is an option, I also can deliver by car within a range of 200 miles around Milton Keynes (at fuel cost).
Detailed info about the speaker available on Troel's hompage troelsgravesen.dk
GBP 599 (for the pair) for self-collectors in the UK (or plus fuel cost if I deliver and you don't live too far away from Milton Keynes).
These speakers wwere built from a kit from Jantzen Audio in Denmark (level 2 crossover parts).
The enclosure has been built from baltic birch 18mm. The surface is so far unfinished and the buyer can decide if they just want to put lacqeur on top or a veneer.
Comes with the original instructions from Troels.
Scanspeak drivers are
D2608/913000 tweeter
15W/8434G00 mid range
22W/8534G00 woofer
The crossover is built from parts of that Jantzen kit. The upgraded binding posts are the components that did not come with the kit.
I also have applied L-pads for the mid and high range, but you can unplug those if you like the original sound better.
because of the weight and fragile nature I cannot ship these speakers via post.
Collection in Milton Keynes is an option, I also can deliver by car within a range of 200 miles around Milton Keynes (at fuel cost).
For Sale Bridged RB-TA3020-3 1.2kW Tripath evaluation board
- By brunomiguel
- Swap Meet
- 11 Replies
RB-TB TA-3020 1.2Kw class T amplifier for sale 160€
Genuine working Tripath evaluation pcb board with heatsinks mounting screws not supplied.
Tracked shipment to European union
Skematics sended together with articles.
Payment by PP
If you enjoy this kind of stuff check my stuff related:
https://www.ebay.de/usr/dialedinmusic?_trksid=p4429486.m3561.l2559
Attachments
I need help with identifying a resistor (R53) from a Kicker CXA600.5
I need help with identifying a resistor (R53) from a Kicker CXA600.5
I fix amps as a hobby and got this Kicker CXA600.5 for free and do believe this missing resistor is the problem.
I traced the remote circuit and it lead me to R53. If anyone has a schematic and willing to share, I will be so thankful.
Thanks
Jean
I fix amps as a hobby and got this Kicker CXA600.5 for free and do believe this missing resistor is the problem.
I traced the remote circuit and it lead me to R53. If anyone has a schematic and willing to share, I will be so thankful.
Thanks
Jean
What is the purpose of supplying the AC to rectifier through capacitors
- By Bas Horneman
- Power Supplies
- 33 Replies
Like in the encircled part of the schematic.
High WAF Dynamic Speaker System Build
Hi,
This is a build thread of a speaker system for my living room built on the unitized image wavguide design from Patrick Bateman: https://www.diyaudio.com/community/threads/unitized-image-control-waveguide.319698/page-16
The waveguide being used is constant directivity and offers about 360Hz-20khz range at 96db/w/m using 4 midranges and one tweeter. I went off this design because one of the best speakers I ever heard were the Lambda Acoustic Unity's (licensed from Tom Danley). They did everything right, so this design has similar performance in a smaller waveguide.
- I need the bass cabinet to be dynamic, loud, crisp and have a wide sweet spot. My musical tastes are all over the place, rock, fusion, synthwave, jazz, etc.. Metal is the most demanding as it needs to have crisp kicks and snare along with the wide bandwidth of the rest of the instruments. To find out what freqeuncies need special attention, I took a spectrum analysis of a demanding track "God's Equation" by Pagans Mind as shown below:
As you can see, a substantial amount of musical energy is focused in between about 350hz to 40hz. Kick drums range in 40 to about 100Hz, snare peaks around 193hz, with activity up to around 425hz. Toms focus around 105 to 158hz. This explains why I always liked a higher crossover frquency in my car and never liked the 80hz, it crosses over in the middle of the kick drum. The good news as the around 300 - 400 hz, there seems to be less peaks for various types of msuic of that style, so a crossover can go right there.
- The speakers need to fit both sides of the fireplace in these areas for the WAF to be high (Wife Acceptance Factor) and would be disguised to look like a radiator (like on the left) or a cabinet of some sort. I have a space of up to about 32" long x 18"deep x 25"high. It could be up to 30" if the design has to use that height. The idea is to have the horn sit in it's own box on the top, which brings it to about 30" anyway.
That being said, these are the constraints and objectives:
1. Bass bin that covers 40hz to 400hz,
2. High sensitivity around 97+ db/w/m. Why? I don't know why, but for some reason big speakers sound more dynamic, even at lower volume levels despite the math showing the same output level.
3. Fit within an area of up to about 32" long x 18"deep x 25"high (81cm x 45cm x 64cm). That a volume of 8-10 cu. ft (235L - 283L) Must be box-shaped, this will look like a cabinet or radiator cover with paint and "creativity".
4. MiniDSP, FIR filters, Active Filters are all ok for the bass cabinet. The waveguide would ideally remain passive.
5. The waveguide and be a part of the cabinet or separate.
6. I am knowledgeable in work working to cut and glue panels.
7. sound dynamic at both lower and high volume levels. I typically listen around 85db-90db. I don't plan on blasting concert levels, but want the option.
8. I am open to any and all ideas to achieve the objectives above, breaking conventional rules is ok. 🙂
Some ideas that I have been thinking about for a while:
I'll be going over some simulations to see what may be possible. I would greatly appreciate anyone's input - any and every suggestion would be greatly appreciated!
This is a build thread of a speaker system for my living room built on the unitized image wavguide design from Patrick Bateman: https://www.diyaudio.com/community/threads/unitized-image-control-waveguide.319698/page-16
The waveguide being used is constant directivity and offers about 360Hz-20khz range at 96db/w/m using 4 midranges and one tweeter. I went off this design because one of the best speakers I ever heard were the Lambda Acoustic Unity's (licensed from Tom Danley). They did everything right, so this design has similar performance in a smaller waveguide.
- I need the bass cabinet to be dynamic, loud, crisp and have a wide sweet spot. My musical tastes are all over the place, rock, fusion, synthwave, jazz, etc.. Metal is the most demanding as it needs to have crisp kicks and snare along with the wide bandwidth of the rest of the instruments. To find out what freqeuncies need special attention, I took a spectrum analysis of a demanding track "God's Equation" by Pagans Mind as shown below:
As you can see, a substantial amount of musical energy is focused in between about 350hz to 40hz. Kick drums range in 40 to about 100Hz, snare peaks around 193hz, with activity up to around 425hz. Toms focus around 105 to 158hz. This explains why I always liked a higher crossover frquency in my car and never liked the 80hz, it crosses over in the middle of the kick drum. The good news as the around 300 - 400 hz, there seems to be less peaks for various types of msuic of that style, so a crossover can go right there.
- The speakers need to fit both sides of the fireplace in these areas for the WAF to be high (Wife Acceptance Factor) and would be disguised to look like a radiator (like on the left) or a cabinet of some sort. I have a space of up to about 32" long x 18"deep x 25"high. It could be up to 30" if the design has to use that height. The idea is to have the horn sit in it's own box on the top, which brings it to about 30" anyway.
That being said, these are the constraints and objectives:
1. Bass bin that covers 40hz to 400hz,
2. High sensitivity around 97+ db/w/m. Why? I don't know why, but for some reason big speakers sound more dynamic, even at lower volume levels despite the math showing the same output level.
3. Fit within an area of up to about 32" long x 18"deep x 25"high (81cm x 45cm x 64cm). That a volume of 8-10 cu. ft (235L - 283L) Must be box-shaped, this will look like a cabinet or radiator cover with paint and "creativity".
4. MiniDSP, FIR filters, Active Filters are all ok for the bass cabinet. The waveguide would ideally remain passive.
5. The waveguide and be a part of the cabinet or separate.
6. I am knowledgeable in work working to cut and glue panels.
7. sound dynamic at both lower and high volume levels. I typically listen around 85db-90db. I don't plan on blasting concert levels, but want the option.
8. I am open to any and all ideas to achieve the objectives above, breaking conventional rules is ok. 🙂
Some ideas that I have been thinking about for a while:
- Open baffle with two SB Audience Bianco-15OB350 15" Open Baffle Woofers per side. Maximum distance I can keep drivers from wall (at the baffle) would be 18". *I have tried this approach about 12 years ago with early 15" Acoustic elegance dipole woofers on sale. I remember good clean bass with one 15" woofer, so much that it occurred a single one woofer would have been ok, even being close to a wall. That was the "rule breaker" concept as it had the best bass I ever heard in terms of quality. I don't remember regarding dynamics. I had used DSp at the time with a Behringer feedback destroyer unit.
- Sealed cabinet with a 6ft. space using a single SB Audience Bianco-15OB350 15" Open Baffle Woofer Joseph Crower had good success with this, as it showed good promised with critical damping. https://josephcrowe.com/blogs/news/...y-15-2-way-monitor-using-sb-audience-products I was thinking adding resonant chambers inside to damp the impedance peaks like the Hegeman enclosure design from this thread: https://www.diyaudio.com/community/threads/3d-printed-metamaterials.360739/page-5
- Front loaded horn similar to the University Classic, but would need to be reshaped to fit the 18" depth, not sure this is practical for 40hz-400hz. Maybe something like William Cowan's Horn Sub Jr., but with a side scoop to make it front firing: https://www.cowanaudio.com/hornsubjr.html
- Karlsonator / Karlson cabinet of some sort. Freddi speaks highly of these cabinets, but it would need to lay on it's side. They don't simulate well, but I hear lots of praises for it's sound.
- Front loaded bass refelx like Altec A7, but not so large. Joseph Crowes awesome 1798 cabinet looks VERY promising to work off of, but it's too big for my space. However, maybe squashed down/ isobaric loading and with Onken Style vents / passive radiators could do it in the volume I have to work with: https://josephcrowe.com/blogs/news/bass-cabinet-no-1798 I could integrate the waveguide into the top part of the woofer horn.
- Slot Loaded open baffle, or slot loaded closed - Brings down distortion, but concerned with frequency response about 250hz (maybe not an issue?).
- Something Wild and Different - Hybrid Front loaded horn with tapped horn aka Cyclops style tapped horn? 6th/8th order band pass? Front loaded Horn with woofer feeding a Paraline lens that goes into a conical horn?
I'll be going over some simulations to see what may be possible. I would greatly appreciate anyone's input - any and every suggestion would be greatly appreciated!