Help plz, what is this capacitor?
- By snowjx
- Solid State
- 3 Replies
Hi,
Its a c17 capacitor in Musical Fidelity A1, i beed to replace it.
Anyone know what type of capacitor it is ? And what is the spec?
Its a c17 capacitor in Musical Fidelity A1, i beed to replace it.
Anyone know what type of capacitor it is ? And what is the spec?
Are SS 18W/8545-00 and 18W/8545 identical?
- Multi-Way
- 13 Replies
Am I correct in assuming that this 18W/8545 driver is identical to 18W/8545-00, even though it doesn't say "-00"?
Walsh Infinity tweeter rebuild
- By rayivers
- Planars & Exotics
- 0 Replies
After all the excellent info and help I've received from this and other online forums, I wanted to give back at least a little re my recent Infinity Walsh tweeter rebuild / diaphragm replacement. I was hoping to improve the efficiency and power handling if possible. It came out great, a little louder than my other all-original one with slightly better dynamics on loud transients. I'm running a separate 50W/ch HF amp with 3.5kHz 12dB/octave passive line-level crossovers (Harrison Labs) + 10uF Solen coupling caps for a total of 18dB/oct. These tweeters never cease to amaze me - all kinds of music, dialogue, falling rain on pavement, wind in tree leaves, cymbals/hi-hats/bells etc, shell casings 🙂 - you name it.
The base is machined Delrin, and I also had 'top hats' made that I didn't use (blocked out too much top radiation). I have diagrams for both if anyone needs them.
I tried unwinding & resoldering the voice coil wire after reading about it online, but it was too damaged to salvage. The voice coil was partially burnt black; I was amazed, as these tweeters were bought NIB from Infinity in the late '80s and sat untouched in their boxes for 30+ years, then used less than an hour before one failed on a loud snap-transient, blowing a 1A inline fuse. Now that it's apart I'm sure it was repaired and re-sold as "new", as the diaphragm center-hole cutting and cone gluing were awful (the other one looks perfect). I think the transient may have caused this already burnt coil to DC-short to the gap OD. The center post had a huge off-center blob of epoxy at its base which rubbed the new diaphragm. With careful taping and a little luck, I managed to Dremel this away without cutting into metal or filling the gap with crap.
After a trip to my machinist for advice and punching holes thru several ebay titanium diaphragms, I ended up using the one below ('scarlettchen' at ebay). The diamond-shaped surround stampings add a lot of stiffness & support:
The titanium in this diaphragm's dome is thick enough to punch, but the punch should be fresh and tight (my machinist's wasn't, but it still made a fairly clean .75" hole). The coil got torqued a little in the process though, so I ordered another & cut the hole by hand using a disposable scalpel & 4" Fiskars scissors (came out OK, but a little close on one side which made epoxying scary later). If I was rebuilding a conventional dome tweeter I would've preferred a thinner diaphragm, but supporting a big aluminum cone is a heavy lift for a tweeter, and with one possibly alignment-related blowout already I'd rather be safe than sorry this time. This unit also has twice the OEM winding length, which should significantly improve thermal power handling.
This diaphragm's flat, angled leads required ground channels in the plastic washer & top of the base (magnet structure) for the leads to fit into, which were painted for insulation / easy sliding / rustproofing.
The OEM diaphragm uses a precision plastic washer for clamping & centering which fits into an equally precise circular recess in the base, and worked just fine. After making up a 1"-diameter paper shim with 25lb smooth-stock paper and fitting it to the pole piece, I put the washer in the recess, applied 4 small drops of contact cement to the top of it, then immediately slid the voice coil over the shim & the diaphragm down on the washer / glue drops (no drying time before contact) & screwed down the top flange plate medium-tight. This is not the way contact cement is normally used, but the diaphragm centered perfectly on the thinly-spread wet glue w/no excess, and came out great. The contact-cement joint only has to hold the diaphragm & washer together when they're removed to pull the shim out, which wasn't easy... I ended up sliding pieces of Scotch tape down each side of the gap, & luckily one of them stuck to the shim paper enough to pull it out.
After cutting, grinding, and painting:
Top plate on:
I then set up the gluing jig (below).
It took a ton of fiddling with cardboard height shims on the center box, the clear cup lid centering aid, the orange 'funnel', etc. to get everything aligned - I also had to figure out an 'escape plan' to get the completed tweeter out of the jig after the cone was glued in place - and then many dry runs inserting & aligning the cone quickly and correctly, but finally I managed to to epoxy it to the diaphragm. I looked at a number of epoxies - many were opaque and/or set up too quickly for my taste - finally settling on Devcon 14251 clear epoxy (2-part syringe, 8-10 min. set time, 12 hr cure). I painted the epoxy on the surround/VC OD area & applied it to the cone edge with my fingertip, lowered the cone thru the jig and onto the diaphragm, then added extra epoxy to the bottom cone ID with the brush. I'd recommend absolutely NO caffeine, and a good night's sleep beforehand. 🙂
24 hrs later, I cut away two large sections of the orange funnel thing, slid it to the side & removed it, then lifted the tweeter out thru the jig center opening from the bottom. I tested it with .25W / 10Hz (no VC rubbing heard or felt), then 1W 2khz - 20kHz sine/square sweeps; as expected some weak resonances were present, but nothing major.
I got more Polyfil on Amazon, but my original stuff was pre-cut to size & still good so I re-used it. It had packed down a bit, so I pulled it up & apart so it nearly filled the entire cone loosely.
Next was the foam. I wanted precisely-cut foam circles and wasn't impressed with Infinity's single undersized one, so I went with something that to my ears worked better - two different foams, each for its own task. These were waterjet-cut by Foam N' More (www.foamforyou.com) for a very reasonable price - Michelle was extremely helpful. After trying several things, here's what I ended up using:
Foam 1 (in top ID of cone): Regicell 30 ppi polyethylene reticulated, black, 0.5" thick, .375" ID / ctr hole, 3.25" OD
This foam supports & centers the cone, and damps mechanical resonances in the moving system. It compresses readily but is stiffer than Foam 2 below, & is @ 90% acoustically transparent. Foam N' More stocks it, in 24 x 36" sheets (1 sheet minimum). I trimmed the bottom edge OD slightly so it would slide into the cone without binding. I was very careful not to let it snag the cone edge or stress the cone in any way.
Foam 2 (fits flush on top of Foam 1): 80 ppi polyurethane reticulated, black, 0.5" thick, .375" ID, 3.35" OD
This foam damps the reflected wave into the cone interior, minimizing acoustic resonances. It is softer and denser than Foam 1, and is @ 20-30% acoustically transparent. This foam appears identical to what Infinity used, and was not easy to find - Merryweather Foam makes it (p/n 80PPI.5"XHALF I think, www.merryweather.com) and Nick there was kind enough to send me free samples as they have huge minimum orders. I then sent the sample foam to Foam N' More for cutting, which they were happy to do. Nearly any open-cell 80-100 ppi polyurethane foam should work fine for Foam 2 in a 2-foam setup, and for a single-foam Infinity setup if it's stiff enough (like the Merryweather foam) AND sized correctly to not stress the cone glue seam (3.20" OD, trim bottom edge if needed).
Here's the OEM foam on the left (@ 3.125" OD, degraded) and the new 30 ppi Regicell foam on the right (3.40" OD, way too big - it was my 1st attempt). The new foam's center hole looks like crap in this pic, but it's perfectly round & centered. The 80 ppi polyurethane foam mentioned above is shown in my 1st pic, it looks nearly identical to the OEM foam below.
I used the tweeters for a while with no foam at all (just Polyfil), and also with only Foam 2 placed just above the cone edge. With Polyfil-only they were noticeably louder (especially from the top - mine reflect off a 45° knee wall 14" above), with more hi-mids & an edgy / sibilant tone. Adding Foam 2 dropped the reflected level & mids a lot, but the edginess remained until both foams were used w/Foam 1 contacting the cone, when it instantly vanished.
Well, that's about it for the rebuild. I also made up a tweeter protector for these so (hopefully) this ordeal will never be repeated, and at some point I'll post about that. I might also have the rest of the Merryweather sample foam cut for sale on ebay at some point. The pics aren't displaying as I hoped they would, any suggestions appreciated.
The base is machined Delrin, and I also had 'top hats' made that I didn't use (blocked out too much top radiation). I have diagrams for both if anyone needs them.
I tried unwinding & resoldering the voice coil wire after reading about it online, but it was too damaged to salvage. The voice coil was partially burnt black; I was amazed, as these tweeters were bought NIB from Infinity in the late '80s and sat untouched in their boxes for 30+ years, then used less than an hour before one failed on a loud snap-transient, blowing a 1A inline fuse. Now that it's apart I'm sure it was repaired and re-sold as "new", as the diaphragm center-hole cutting and cone gluing were awful (the other one looks perfect). I think the transient may have caused this already burnt coil to DC-short to the gap OD. The center post had a huge off-center blob of epoxy at its base which rubbed the new diaphragm. With careful taping and a little luck, I managed to Dremel this away without cutting into metal or filling the gap with crap.
After a trip to my machinist for advice and punching holes thru several ebay titanium diaphragms, I ended up using the one below ('scarlettchen' at ebay). The diamond-shaped surround stampings add a lot of stiffness & support:
The titanium in this diaphragm's dome is thick enough to punch, but the punch should be fresh and tight (my machinist's wasn't, but it still made a fairly clean .75" hole). The coil got torqued a little in the process though, so I ordered another & cut the hole by hand using a disposable scalpel & 4" Fiskars scissors (came out OK, but a little close on one side which made epoxying scary later). If I was rebuilding a conventional dome tweeter I would've preferred a thinner diaphragm, but supporting a big aluminum cone is a heavy lift for a tweeter, and with one possibly alignment-related blowout already I'd rather be safe than sorry this time. This unit also has twice the OEM winding length, which should significantly improve thermal power handling.
This diaphragm's flat, angled leads required ground channels in the plastic washer & top of the base (magnet structure) for the leads to fit into, which were painted for insulation / easy sliding / rustproofing.
The OEM diaphragm uses a precision plastic washer for clamping & centering which fits into an equally precise circular recess in the base, and worked just fine. After making up a 1"-diameter paper shim with 25lb smooth-stock paper and fitting it to the pole piece, I put the washer in the recess, applied 4 small drops of contact cement to the top of it, then immediately slid the voice coil over the shim & the diaphragm down on the washer / glue drops (no drying time before contact) & screwed down the top flange plate medium-tight. This is not the way contact cement is normally used, but the diaphragm centered perfectly on the thinly-spread wet glue w/no excess, and came out great. The contact-cement joint only has to hold the diaphragm & washer together when they're removed to pull the shim out, which wasn't easy... I ended up sliding pieces of Scotch tape down each side of the gap, & luckily one of them stuck to the shim paper enough to pull it out.
After cutting, grinding, and painting:
Top plate on:
I then set up the gluing jig (below).
It took a ton of fiddling with cardboard height shims on the center box, the clear cup lid centering aid, the orange 'funnel', etc. to get everything aligned - I also had to figure out an 'escape plan' to get the completed tweeter out of the jig after the cone was glued in place - and then many dry runs inserting & aligning the cone quickly and correctly, but finally I managed to to epoxy it to the diaphragm. I looked at a number of epoxies - many were opaque and/or set up too quickly for my taste - finally settling on Devcon 14251 clear epoxy (2-part syringe, 8-10 min. set time, 12 hr cure). I painted the epoxy on the surround/VC OD area & applied it to the cone edge with my fingertip, lowered the cone thru the jig and onto the diaphragm, then added extra epoxy to the bottom cone ID with the brush. I'd recommend absolutely NO caffeine, and a good night's sleep beforehand. 🙂
24 hrs later, I cut away two large sections of the orange funnel thing, slid it to the side & removed it, then lifted the tweeter out thru the jig center opening from the bottom. I tested it with .25W / 10Hz (no VC rubbing heard or felt), then 1W 2khz - 20kHz sine/square sweeps; as expected some weak resonances were present, but nothing major.
I got more Polyfil on Amazon, but my original stuff was pre-cut to size & still good so I re-used it. It had packed down a bit, so I pulled it up & apart so it nearly filled the entire cone loosely.
Next was the foam. I wanted precisely-cut foam circles and wasn't impressed with Infinity's single undersized one, so I went with something that to my ears worked better - two different foams, each for its own task. These were waterjet-cut by Foam N' More (www.foamforyou.com) for a very reasonable price - Michelle was extremely helpful. After trying several things, here's what I ended up using:
Foam 1 (in top ID of cone): Regicell 30 ppi polyethylene reticulated, black, 0.5" thick, .375" ID / ctr hole, 3.25" OD
This foam supports & centers the cone, and damps mechanical resonances in the moving system. It compresses readily but is stiffer than Foam 2 below, & is @ 90% acoustically transparent. Foam N' More stocks it, in 24 x 36" sheets (1 sheet minimum). I trimmed the bottom edge OD slightly so it would slide into the cone without binding. I was very careful not to let it snag the cone edge or stress the cone in any way.
Foam 2 (fits flush on top of Foam 1): 80 ppi polyurethane reticulated, black, 0.5" thick, .375" ID, 3.35" OD
This foam damps the reflected wave into the cone interior, minimizing acoustic resonances. It is softer and denser than Foam 1, and is @ 20-30% acoustically transparent. This foam appears identical to what Infinity used, and was not easy to find - Merryweather Foam makes it (p/n 80PPI.5"XHALF I think, www.merryweather.com) and Nick there was kind enough to send me free samples as they have huge minimum orders. I then sent the sample foam to Foam N' More for cutting, which they were happy to do. Nearly any open-cell 80-100 ppi polyurethane foam should work fine for Foam 2 in a 2-foam setup, and for a single-foam Infinity setup if it's stiff enough (like the Merryweather foam) AND sized correctly to not stress the cone glue seam (3.20" OD, trim bottom edge if needed).
Here's the OEM foam on the left (@ 3.125" OD, degraded) and the new 30 ppi Regicell foam on the right (3.40" OD, way too big - it was my 1st attempt). The new foam's center hole looks like crap in this pic, but it's perfectly round & centered. The 80 ppi polyurethane foam mentioned above is shown in my 1st pic, it looks nearly identical to the OEM foam below.
I used the tweeters for a while with no foam at all (just Polyfil), and also with only Foam 2 placed just above the cone edge. With Polyfil-only they were noticeably louder (especially from the top - mine reflect off a 45° knee wall 14" above), with more hi-mids & an edgy / sibilant tone. Adding Foam 2 dropped the reflected level & mids a lot, but the edginess remained until both foams were used w/Foam 1 contacting the cone, when it instantly vanished.
Well, that's about it for the rebuild. I also made up a tweeter protector for these so (hopefully) this ordeal will never be repeated, and at some point I'll post about that. I might also have the rest of the Merryweather sample foam cut for sale on ebay at some point. The pics aren't displaying as I hoped they would, any suggestions appreciated.
Attachments
MM Phono Pre with balanced input
- By ZackPlonk
- Analogue Source
- 27 Replies
Hello,
As a learning project to push myself into starting to design my own stuff rather I have been trying to come up with (yet another) phono stage.
I wanted something with a balanced input b/c I think the superior CMMR is worth it in my particular case. I do have quite a bit of EMI where I'm listening to records. So my design goals:
- Optimized for MM. (For MC carts, a head-amp can be added later)
- Balanced input to cancel out CM interference
- Keep capacitors out of the signal path as much as possible
- passive RIAA
- Optional sub-sonic/rumble HPF
So using what I've learned so far about op-amps and looking at what many others did, I've put something tohether in LTSpice.
I'm using an offset compensation through another op-amp in order to get rid of the DC offset introduced in the initial two stages.
The rumble filter is a 3rd order S-K Q=.707 filter with a 20Hz cutoff. The idea is to have switch that selects the output jacks to either connect to U3 directly (out1) or to alternatively to the HPF output (out2)
Resistors in the RIAA filter should be .1% types and the caps there should be 3% types.
I think I'm pretty ignorant about all the things I don't know yet, so if someone can spare a few minutes to look at this thing and can share some feedback on what to do differently that would be awesome...
Some points I'm wondering about in particular:
- Better choices for op-amps?
- Is it worth considering a discrete approach for the first stage instead of op-amp
- is a a good idea to place the HPF as the last piece of the chain? Would there be anything advantegeous about putting it between the RIAA and the second gain stage?
- is the offset compensation a worthwhile approach or should a DC blocking cap in the output be considered. It might just be a matter of taste, but I'd love to read opinions on this...
- Is there a better way to wire up the input to have best flexibility with balanced and single-ended sources? Also modifications to the input loading resistance and capacitance (R1/R2, C1) are interesting to me. How can that be put into practice? Some RCA jacks in parallel where one could fit caps and resistors seems to be one way to go about that but the fact that the resistive load is split across R1/R2 makes this more complicated. Is there a way to have a single load resistor and still have a balanced input?
Here's the schematic and a bode plot w/ and w/o HPF
Cheers,
Lars
As a learning project to push myself into starting to design my own stuff rather I have been trying to come up with (yet another) phono stage.
I wanted something with a balanced input b/c I think the superior CMMR is worth it in my particular case. I do have quite a bit of EMI where I'm listening to records. So my design goals:
- Optimized for MM. (For MC carts, a head-amp can be added later)
- Balanced input to cancel out CM interference
- Keep capacitors out of the signal path as much as possible
- passive RIAA
- Optional sub-sonic/rumble HPF
So using what I've learned so far about op-amps and looking at what many others did, I've put something tohether in LTSpice.
I'm using an offset compensation through another op-amp in order to get rid of the DC offset introduced in the initial two stages.
The rumble filter is a 3rd order S-K Q=.707 filter with a 20Hz cutoff. The idea is to have switch that selects the output jacks to either connect to U3 directly (out1) or to alternatively to the HPF output (out2)
Resistors in the RIAA filter should be .1% types and the caps there should be 3% types.
I think I'm pretty ignorant about all the things I don't know yet, so if someone can spare a few minutes to look at this thing and can share some feedback on what to do differently that would be awesome...
Some points I'm wondering about in particular:
- Better choices for op-amps?
- Is it worth considering a discrete approach for the first stage instead of op-amp
- is a a good idea to place the HPF as the last piece of the chain? Would there be anything advantegeous about putting it between the RIAA and the second gain stage?
- is the offset compensation a worthwhile approach or should a DC blocking cap in the output be considered. It might just be a matter of taste, but I'd love to read opinions on this...
- Is there a better way to wire up the input to have best flexibility with balanced and single-ended sources? Also modifications to the input loading resistance and capacitance (R1/R2, C1) are interesting to me. How can that be put into practice? Some RCA jacks in parallel where one could fit caps and resistors seems to be one way to go about that but the fact that the resistive load is split across R1/R2 makes this more complicated. Is there a way to have a single load resistor and still have a balanced input?
Here's the schematic and a bode plot w/ and w/o HPF
Cheers,
Lars
Leak 2000 Tuner/amp
- Solid State
- 0 Replies
I bought one of these fifteen years ago quite cheaply on eBay to replace a Philips 790, I'd bought new in 1972 which went U/S.
At the same time I'd bought some Goodmans Havant speakers and a Philips 308 turntable.
A couple of years later I bought new a Sharp cassette deck.
The turntable and cassette I fitted new belts about fifteen years ago, but they still work fine.
I use this system mostly to play mp3s via a couple of Rock-Ola 507 wall boxes and 3rd gen iPods. (It's all about "nostalgia" for me as I have also two vinyl jukeboxes).
Unfortunately, the Leak started "motorboating" a week or so ago so has gone in for repair.
But in the meantime, I spotted a rather sad looking Leak 2000 on e-Bay for not a lot of money. They can go for £150, but I got it for £56. The vendor assured me that it was working condition. I was also impressed how well he packed it up to send it.
As promised, it's in perfect working condition, although the tuning cord is a bit noisy in one place but doesn't stick, no mains hum at all. But the cabinet was "dog rough."
As I've a service manual, I'd previously got via a pdf from another enthusiast, I knew the top and sides came off quite easily. As they have wood veneer I guess they were added to the chassis at the end of the assembly.
The top had a lot of scratches and it was obvious the set had been stored on one end for a long time in a dusty area and dragged about several times.
But with a couple of grades of sandpaper and some Golden Oil polish and conditioner, it came back in a very presentable condition.
This was the worst side.
Anyway, it is working perfectly.
( I made this video before cleaning up the cabinet).
1970s Leak 2000 Tuner amp - YouTube
I'll still get the other repaired and this one can go in my "office" and the Rotel I bought cheaply on eBay early this year can become a spare.
This is playing through over-size speakers I put in this non=working sixties Rock-Ola jukebox wall box.
https://www.youtube.com/watch?v=F7dpvYw3fAE
I've since bought some boolcase speakers for it.
At the same time I'd bought some Goodmans Havant speakers and a Philips 308 turntable.
A couple of years later I bought new a Sharp cassette deck.
The turntable and cassette I fitted new belts about fifteen years ago, but they still work fine.
I use this system mostly to play mp3s via a couple of Rock-Ola 507 wall boxes and 3rd gen iPods. (It's all about "nostalgia" for me as I have also two vinyl jukeboxes).
Unfortunately, the Leak started "motorboating" a week or so ago so has gone in for repair.
But in the meantime, I spotted a rather sad looking Leak 2000 on e-Bay for not a lot of money. They can go for £150, but I got it for £56. The vendor assured me that it was working condition. I was also impressed how well he packed it up to send it.
As promised, it's in perfect working condition, although the tuning cord is a bit noisy in one place but doesn't stick, no mains hum at all. But the cabinet was "dog rough."
As I've a service manual, I'd previously got via a pdf from another enthusiast, I knew the top and sides came off quite easily. As they have wood veneer I guess they were added to the chassis at the end of the assembly.
The top had a lot of scratches and it was obvious the set had been stored on one end for a long time in a dusty area and dragged about several times.
But with a couple of grades of sandpaper and some Golden Oil polish and conditioner, it came back in a very presentable condition.
This was the worst side.
Anyway, it is working perfectly.
( I made this video before cleaning up the cabinet).
1970s Leak 2000 Tuner amp - YouTube
I'll still get the other repaired and this one can go in my "office" and the Rotel I bought cheaply on eBay early this year can become a spare.
This is playing through over-size speakers I put in this non=working sixties Rock-Ola jukebox wall box.
https://www.youtube.com/watch?v=F7dpvYw3fAE
I've since bought some boolcase speakers for it.
Assistance with waveform description from piezo 'field recording'
- By stylofoam
- Everything Else
- 1 Replies
Hi guys, first post, I've just started touching electronics for the first time since high school in the 90s. I'm interested in digging deeper into the rabbit hole.
I know this is tangential to most things here, but i built this piezo preamp Piezo contact microphone hi-Z amplifier – low noise version – Richard Mudhar
I'm running a scarlet 2i2 powered from a OnePlus 6 phone using USB Audio Recorder Pro android driver over a new anker usbc to usbc cable, with the idea of having a portable rig to get DIY contact field recordings. I'm well aware you might be wincing in pain by now.
My initial tests have an unacceptable amount of popping noise which I'm assuming is from high levels of static when i am trying to record very low signals at high gain. I made a grounding mat from some mesh I intend to attach to steel structures for discharge.
I recognise there are numerous open ended issues here and I have rough plans to build a pair of updated pre amps, the reason I took it to this forum rather than his is because I'm considering adding another amp stage or switchable gain capacitors and high/low pass filter circuits etc. My ignorance should be apparent at this stage.
I have hopefully successfully attached an image showing what looks like a complete polarity switch on the audio. Could someone tell me what this phenomenon is. I'm assuming this is very basic stuff and at ultra-aggressive levels.
Please feel free to also tell me if there's somewhere better to take my discussion.
Thank you for your time and patience and I appreciate any assistance.
I know this is tangential to most things here, but i built this piezo preamp Piezo contact microphone hi-Z amplifier – low noise version – Richard Mudhar
I'm running a scarlet 2i2 powered from a OnePlus 6 phone using USB Audio Recorder Pro android driver over a new anker usbc to usbc cable, with the idea of having a portable rig to get DIY contact field recordings. I'm well aware you might be wincing in pain by now.
My initial tests have an unacceptable amount of popping noise which I'm assuming is from high levels of static when i am trying to record very low signals at high gain. I made a grounding mat from some mesh I intend to attach to steel structures for discharge.
I recognise there are numerous open ended issues here and I have rough plans to build a pair of updated pre amps, the reason I took it to this forum rather than his is because I'm considering adding another amp stage or switchable gain capacitors and high/low pass filter circuits etc. My ignorance should be apparent at this stage.
I have hopefully successfully attached an image showing what looks like a complete polarity switch on the audio. Could someone tell me what this phenomenon is. I'm assuming this is very basic stuff and at ultra-aggressive levels.
Please feel free to also tell me if there's somewhere better to take my discussion.
Thank you for your time and patience and I appreciate any assistance.
Need help with designing a throat adapter for HF108 to big old Vitavox(?) biradial
dear experts from diyaudio,
After a long pause in speaker building I've started the design of a new speaker, I will open a separate threat for the speaker project.
At this moment in time I have some questions on how to design a throat adapter.
I bought two big old cast biradial horns, brand is unknown, size is 62x24x30cm.
These have a totally weird un-standard throat size of 41mm.
Inspired by the "Shadow of The Colossus" build thread of forum member Legis I decided to go with Faital Pro HF108 drivers, which of course have a 1" throat.
I plan to have adapters 3D printed but I'm stuck at how I should make the mechanical design.
According to the datasheet of the HF108 it has an exit angle of 31 degrees.
The horn has a 13 degrees entrance angle looking from the top, and a -3 degrees entrance angle looking from the side, see the attached sketch (black = horn, green = adapter, orange = HF108).
There are several ways to design the adapter (assuming the adapter will be a simple conical design):
1 - Extend the 31 degrees of the driver to go the 41mm opening of the horn --> one sharp corner to the entrance of the horn
2 - Find some kind of average angle between the driver and the horn?? --> two corners that are less sharp.
3 - other smart idea?
3D printing would of course enable non-conical shapes but my 3D CAD skills are rather under developed 🙂
Can anybody give my some advice?
thanks, kind regards,
Peter
the Netherlands
After a long pause in speaker building I've started the design of a new speaker, I will open a separate threat for the speaker project.
At this moment in time I have some questions on how to design a throat adapter.
I bought two big old cast biradial horns, brand is unknown, size is 62x24x30cm.
These have a totally weird un-standard throat size of 41mm.
Inspired by the "Shadow of The Colossus" build thread of forum member Legis I decided to go with Faital Pro HF108 drivers, which of course have a 1" throat.
I plan to have adapters 3D printed but I'm stuck at how I should make the mechanical design.
According to the datasheet of the HF108 it has an exit angle of 31 degrees.
The horn has a 13 degrees entrance angle looking from the top, and a -3 degrees entrance angle looking from the side, see the attached sketch (black = horn, green = adapter, orange = HF108).
There are several ways to design the adapter (assuming the adapter will be a simple conical design):
1 - Extend the 31 degrees of the driver to go the 41mm opening of the horn --> one sharp corner to the entrance of the horn
2 - Find some kind of average angle between the driver and the horn?? --> two corners that are less sharp.
3 - other smart idea?
3D printing would of course enable non-conical shapes but my 3D CAD skills are rather under developed 🙂
Can anybody give my some advice?
thanks, kind regards,
Peter
the Netherlands
Suitability of ME464 as a multi-entry horn / synergy
- By diyuser2010
- Multi-Way
- 27 Replies
There aren't many photos of this recently released horn circulating yet, so I wanted to post a few and add some commentary.
The finish is a *very* coarse spray applied texture finish. If you desire a domestic friendly finish, be prepared to spend a few hours per horn sanding, priming, sanding and painting these to a satisfactory finish.
No digital measurement tools were used in measuring this horn, so take the tolerance of the measurements to be within 1/32" total.
Compression driver mounting flange thickness 5/16"
Compression driver mounting flange to end of slot inside horn 7 1/8".
Inside of flange to start of horizontal flare rate change on outside of horn 6 9/16"
Using a 3/8" thick mounting plate will give 7 1/16" from the inside of the flange to the horn wall. A 1/2" thick mounting plate would move that to 7 13/16" . Ideally a pair of 6-7" woofers could be used mounted close to the compression driver.
Approximate wall thickness where proposed midrange taps to be drilled - 3/16" - determined by measuring the inside and outside, subtracting the difference and dividing by 2.
Width inside the horn at midrange tap location 1.5 inches approximately. 1.5" + 3/8" + 1" = 1 7/8 inches + flange thickness of woofer /mid if 1/2" mounting plates are used.
The finish is a *very* coarse spray applied texture finish. If you desire a domestic friendly finish, be prepared to spend a few hours per horn sanding, priming, sanding and painting these to a satisfactory finish.
No digital measurement tools were used in measuring this horn, so take the tolerance of the measurements to be within 1/32" total.
Compression driver mounting flange thickness 5/16"
Compression driver mounting flange to end of slot inside horn 7 1/8".
Inside of flange to start of horizontal flare rate change on outside of horn 6 9/16"
Using a 3/8" thick mounting plate will give 7 1/16" from the inside of the flange to the horn wall. A 1/2" thick mounting plate would move that to 7 13/16" . Ideally a pair of 6-7" woofers could be used mounted close to the compression driver.
Approximate wall thickness where proposed midrange taps to be drilled - 3/16" - determined by measuring the inside and outside, subtracting the difference and dividing by 2.
Width inside the horn at midrange tap location 1.5 inches approximately. 1.5" + 3/8" + 1" = 1 7/8 inches + flange thickness of woofer /mid if 1/2" mounting plates are used.
My first subwoofer. Peerless xls10 in passive radiator application
- By 131183914
- Subwoofers
- 11 Replies
Hi.
It's my first audio project done ever. I designed and build it myself. Inspiration was taken from few other projects.
Driver - Peerless xls10
Passive Radiator - Scan Speak Discovery 10
Amplifier - custom build 300W into 4Ohm
Built of double 18mm MDF, Faux leather, Gloss Acrylic
Capacity 20 litres!
Tune to 21Hz
It's my first audio project done ever. I designed and build it myself. Inspiration was taken from few other projects.
Driver - Peerless xls10
Passive Radiator - Scan Speak Discovery 10
Amplifier - custom build 300W into 4Ohm
Built of double 18mm MDF, Faux leather, Gloss Acrylic
Capacity 20 litres!
Tune to 21Hz
First-timer wanting to build a stereo furniture
Hi, i`m thinking of building my own tv bench/furniture with built in speakers.
Inspired by The lemus home classic series.
Yes, i could just buy the lemus one and probably be satisfied, but I want to try a DIY project, maybe get better sound and save some money aswell.
Never built speakers before, so i am sure it`s gonna be a challenge, but i am ready to dive into the DIY madness.
I have sketched up the furniture, and the speaker "boxes" will be about 40cm wide, 35cm deep and 26cm high, thats around 36l in volume. The space between the 2 boxes are around 80cm. So the furniture will be in total about 160cm wide. Thinking of using 19mm(25mm on the front baffle) MDF as a material.
The speakers will be driven by a Harman Kardon Citation Amp (2x125w 8ohm).
First question: what drivers to choose? Thinking of a 2 way system. 6.5" or 8" woofer and a tweeter.
Since i cant move the speakers around in the room i need something with a wide soundstage.
The seas factory is close by so i was thinking of using their elements, but im not locked to that brand by any means.
Budget for the woofers and tweeters are around 500-800euro.
I`m thinking about doing the boxes ported, but no idea if the enclosures are to small?
Next scary part is the making the crossovers, should i buy a pre-made one or try to make my own? 😱
I looking for some clean and fun sound for movies and music. Not planning on a subwoofer, but hopefully i can get some decent bass.
Anyone willing to push me in the right direction? 😛
Not a native english speaker, so sorry in advance 😀
Inspired by The lemus home classic series.
Yes, i could just buy the lemus one and probably be satisfied, but I want to try a DIY project, maybe get better sound and save some money aswell.
Never built speakers before, so i am sure it`s gonna be a challenge, but i am ready to dive into the DIY madness.
I have sketched up the furniture, and the speaker "boxes" will be about 40cm wide, 35cm deep and 26cm high, thats around 36l in volume. The space between the 2 boxes are around 80cm. So the furniture will be in total about 160cm wide. Thinking of using 19mm(25mm on the front baffle) MDF as a material.
The speakers will be driven by a Harman Kardon Citation Amp (2x125w 8ohm).
First question: what drivers to choose? Thinking of a 2 way system. 6.5" or 8" woofer and a tweeter.
Since i cant move the speakers around in the room i need something with a wide soundstage.
The seas factory is close by so i was thinking of using their elements, but im not locked to that brand by any means.
Budget for the woofers and tweeters are around 500-800euro.
I`m thinking about doing the boxes ported, but no idea if the enclosures are to small?
Next scary part is the making the crossovers, should i buy a pre-made one or try to make my own? 😱
I looking for some clean and fun sound for movies and music. Not planning on a subwoofer, but hopefully i can get some decent bass.
Anyone willing to push me in the right direction? 😛
Not a native english speaker, so sorry in advance 😀
Help on Japanese translation of a Jigsaw user manual
- By juanito
- Equipment & Tools
- 10 Replies
Hello,
I'm trying to find out if this vintage Ryobi jigsaw can attach T blades. In these instruccrions (linked below) I can see that there are pictured in page 11. I know that the original blades aren't T or U types, they are straight and with a hole (blades 1, 2 and 3 in page 11). Jut wondering what does it say for the rest of blades which apparently are T type. I guess it's japanesse because the web site is from Japan. Also these instructions are images so no way for me to copy paste text and google translate.
Thanks in advance for your time and help: MUCH apreciated!!:
:
https://www.kyocera-industrialtools.co.jp/products/files/doc/7304528308c705eb60c15be84640eae2.pdf
I'm trying to find out if this vintage Ryobi jigsaw can attach T blades. In these instruccrions (linked below) I can see that there are pictured in page 11. I know that the original blades aren't T or U types, they are straight and with a hole (blades 1, 2 and 3 in page 11). Jut wondering what does it say for the rest of blades which apparently are T type. I guess it's japanesse because the web site is from Japan. Also these instructions are images so no way for me to copy paste text and google translate.
Thanks in advance for your time and help: MUCH apreciated!!:
:https://www.kyocera-industrialtools.co.jp/products/files/doc/7304528308c705eb60c15be84640eae2.pdf
Build Thread: DIY Tube Preamplifier (KSL-M77 Clone-Based)
- By jwpettit
- Analog Line Level
- 3 Replies
Hello! My name is Jeff and I'm new here on DIY Audio, so just wanted to start this thread off with a quick intro post. I'm setting out to build my own Hi-Fi setup with all DIY components and the first piece I'll be tackling will be my preamplifier.
I want to document my process through a thread as 1: I will have many many questions which I know I'll be able to get answered here, and 2: I find it super helpful to review detailed guides complete with photos when learning about these builds, so only fair I give some back. Please note that I am a complete novice to electrical engineering/circuit design, etc. so many of my questions will be "dumb questions". I have a basic understanding of what a resistor and a capacitor do, and know how to solder, but that's about it. Please be patient with me and if already resources exist, kindly point me in the right direction.
I am by trade an industrial designer, so designing consumer products is something that I have quite a bit of experience with, and building this preamp is going to be fun for me. It will be a custom-designed chassis that I will be producing via 3D printing. For the internals, I'm going to be using one of the Chinese KSL-M77 circuit-clone boards as a basis. I know the China clone products can be a bit controversial sometimes so I'd like to make it clear, I am not setting out to build a knockoff of or homage to the M77, rather using using one of these boards as a basis for my custom preamp. My result will be a very very different thing to the original, and I'm making no claims that it will be the same or some match to a genuine M77.
Why did I choose this board? Good question. I was originally considering to use one of the clones to the Marantz M7/Shigeru Wada circuit design which exist (I know those are two different things but they often get used interchangeably). While researching these I discovered the M77, and after reviewing it seemed like a superior design. As mentioned above, I am not very well-versed in electrical engineering, so I'm not able to look at the circuit diagram and understand too much about how it works. However, I do understand a few superiorities this design has:
I ordered a raw board from Aliexpress as I intend to solder in each of the electrical components myself. I feel like this will be a good thing for me to work on in the evenings over watching TV, and wanted to source my own high-quality (audio-grade where possible), name-brand components. Once I receive the board, the first thing I'll do will be to compile a BOM for review.
The other main reason that I wanted to get the un-propagated board is that I intend to assemble it a little differently than the standard configuration. Taking inspiration from some of the M7/Shigeru Wada clone boards I've seen online (see photo), I plan to mount many of the components (particularly large ones) to the underside of the board rather than the top. The goal is to mount the board high in the chassis, and have the tubes exposed outside of the enclosure like many high-end audio components do. I understand that mounting heat-sensitive components like capacitors underneath the board will be thermally sub-optimal, however I plan to design in heat-sinks surrounding them in order to assist with this, and ensure there is plenty of airflow in my design for the chassis.
So excited to get started on this, and hopeful for good advice from those who've built this board before. PCBs should arrive in a couple weeks. Stay tuned for updates!
Thanks!
I want to document my process through a thread as 1: I will have many many questions which I know I'll be able to get answered here, and 2: I find it super helpful to review detailed guides complete with photos when learning about these builds, so only fair I give some back. Please note that I am a complete novice to electrical engineering/circuit design, etc. so many of my questions will be "dumb questions". I have a basic understanding of what a resistor and a capacitor do, and know how to solder, but that's about it. Please be patient with me and if already resources exist, kindly point me in the right direction.
I am by trade an industrial designer, so designing consumer products is something that I have quite a bit of experience with, and building this preamp is going to be fun for me. It will be a custom-designed chassis that I will be producing via 3D printing. For the internals, I'm going to be using one of the Chinese KSL-M77 circuit-clone boards as a basis. I know the China clone products can be a bit controversial sometimes so I'd like to make it clear, I am not setting out to build a knockoff of or homage to the M77, rather using using one of these boards as a basis for my custom preamp. My result will be a very very different thing to the original, and I'm making no claims that it will be the same or some match to a genuine M77.
Why did I choose this board? Good question. I was originally considering to use one of the clones to the Marantz M7/Shigeru Wada circuit design which exist (I know those are two different things but they often get used interchangeably). While researching these I discovered the M77, and after reviewing it seemed like a superior design. As mentioned above, I am not very well-versed in electrical engineering, so I'm not able to look at the circuit diagram and understand too much about how it works. However, I do understand a few superiorities this design has:
- There are more tubes. Maybe they're excessive, and they'll definitely cost more $$$. But more = better right? (Maybe not but go with it anyway.)
- The volume potentiometer is integrated into the circuit itself. When reading about where to integrate the volume pot on a design which doesn't have one there seems to be some healthy debate about whether its best to attenuate on the input or output, with consensus stating optimally its somewhere in the middle. This appears to do that.
- Lines in and out don't share ground between L and R channels.
- Lastly, there's a built-in phono stage. So even though this build costs more, its one less component that I need to buy or build.
I ordered a raw board from Aliexpress as I intend to solder in each of the electrical components myself. I feel like this will be a good thing for me to work on in the evenings over watching TV, and wanted to source my own high-quality (audio-grade where possible), name-brand components. Once I receive the board, the first thing I'll do will be to compile a BOM for review.
The other main reason that I wanted to get the un-propagated board is that I intend to assemble it a little differently than the standard configuration. Taking inspiration from some of the M7/Shigeru Wada clone boards I've seen online (see photo), I plan to mount many of the components (particularly large ones) to the underside of the board rather than the top. The goal is to mount the board high in the chassis, and have the tubes exposed outside of the enclosure like many high-end audio components do. I understand that mounting heat-sensitive components like capacitors underneath the board will be thermally sub-optimal, however I plan to design in heat-sinks surrounding them in order to assist with this, and ensure there is plenty of airflow in my design for the chassis.
So excited to get started on this, and hopeful for good advice from those who've built this board before. PCBs should arrive in a couple weeks. Stay tuned for updates!
Thanks!
