Woohoo! Got everything measured!!! Time to process the files and get after some crossover designs! This (and voicing) is my favorite part of building speakers. So now I have two projects in the works
Well guys I am glad I built these prototypes with cheap wood and spend zero time applying any finish. The six TC9FD's "measured" way better than I expected. Super smooth FR and super low THD. The tweeter measurements were just ok. Woofers were a known (good) going into this project.
I built some prototype xo's based on my XSim and WinPCD work and did a little tweeking. They don't have any glaring issues at all and measure quite well but I was hoping for much much more to my ears.
The sound stage and imaging is no better than the last two way project I did in tradition enclosures I can't blame the TC9FD's... maybe just too many of them.
As they say "easy come and easy go". My next experiment will be an MTMW with only the M's dipole. Probably the same MCM 55-5670 woofer bass bins, but with two larger mids (5.25" or 6.5") and a traditional 1" dome tweeter.
Could you try it with less of the tc9s hooked up? I know this would require a rework of the crossover but it might be worth a try.
For marketing's sake, the other 4 speakers could be referred to as perceptual drivers
My gut feeling right now is that I just don't love that (or possibly any) dipole tweeter and how high I have to cross it. It could also be how far away the upper and lower woofers are. Sort of a line array but not really
I've got a nice leftover piece of poplar that I am going to use to make a couple baffles for yet another test project. This time it will be a much simpler MTM, with dipole Peerless 830656 mids and a monopole DA25BG08-06. The weather here is supposed to be pretty decent for January so a few quick trips to the driveway to cut and router the baffles should be doable hopefully. If this one turns out sounding nice it would be a very affordable project with only four $16 mids, two $26 tweeters (I only paid $15 ea), and two $39 woofers (I only paid $26 ea).
I have found dipoles and open baffles to be deceptively complex. They can be really excellent, but there are many variables which take lots of voicing time. They don't seem to be easy to model. For example, I'm still working on my Indiyana entries after 18 months and they are getting close to being done (maybe)...
I hope you don't give up on the basic concept, it seems like a cool idea to me.
By the way, I went with dipole midwoofers and a monopole tweeter
Not sure if you trashed these yet, but in the past I've taped a cardboard enclosure to the back of my dipole to see where my problem was. Flying/ moving the mic around during sweeps also helped. There are a few projects I wished I would have trashed early.
Ufff... The weather here is making it less and less fun to work outside on speaker projects Looks like I will be turning my attention back to a 6SN7 tube preamp project I never finished as well as starting a new cigar box class D amp for a friend's desk top system.
Yay! I finished the tube preamp project this morning and have been listening to it for a while today. Wow! I love how it sounds. Zero hum and I can barely hear the tiniest bit of hiss with my ear right next to the tweeter. The circuit is based on TubeCad's CCDA topology. I wired in a toggle switch so I can run octal tubes that have either 6.3 volt filaments or 12.6 volt. Right now I'm listening to some NOS Sylvania JAN-12SN7GT's. The JAN stands for Joint-Army-Navy and these have a small US and anchor printed on the base. They are the same tube as the famous 6SN7, only difference is the heater voltage is 12.6 V. Tom send me some RCA 6SN7's he tested so those will go in there next. Here is the money shot with the tubes glowing. I'll try and snap an under the hood shot later.
I built this CCDA preamp circuit with parts that I had in my junk boxes. It was a proof of concept before ordering top notch parts with the exact values. I wanted to make sure I liked how this circuit topology sounded, make sure it wasn't microphonic, and make sure the preamp gain wasn't rediculously high. I've built numerous preamp circuits that claim lots of amazing things... what I usually find is way too much gain and lots of 2nd order harmonics, or a completely sterile sounding cathode follower with less than unity gain. This project (hardwood case and power supply) was originally a 6V6 tube preamp. That thing was crazy microphonic. This one sounds just right to me and it only has a little gain.
The parts I used are within 20% of ideal values but they are just cheap generic resistors and Audyn Q4 caps. My B+ supply is quite a bit too high (348v vs 300v) so lowering that with my filter circuit will greatly reduce the already low AC ripple.
If you haven't noticed by now... I kind of like building this stuff. Anyway, time to order some nicer parts and upgrade this baby.
@Wolf said:
TubeCad the diyaudio poster? He really seems to know what NOT to do, and is a funny writer. Seems he's had a lot of experience in the tube area.
I don't know who that poster is. That diyaudio.com site is a strange place. I am referring to John Broskie.
I don't read it that way. I read it as advancing the state 'of the art (of working with vacuum tubes)'.
He seems really thorough in my limited tube knowledge.
Man I really want to built something tubey, maybe some mono blocks, but I need to finish a bunch of other projects first. Right now, it's recapping a Luxman RX102.
Don't know if anyone cares, but I always layout how the components will be placed and wired. That determines how many terminal strips I will need and where they will be mounted. Here is what I came up with for this project:
What would be the best way to go about inlaying a stripe of different wood like that? Dado or router it out then glue in a strip of whatever wood, then plane it even?
For that look I would rip one piece and glue an accent piece between the two. If all the board are straight when you start you should get good clean lines when you are done.
Both of the methods you mentioned would work as well. They just require very accurate measurements.
@PWRRYD said:
Yay! I finished the tube preamp project this morning and have been listening to it for a while today. Wow! I love how it sounds. Zero hum and I can barely hear the tiniest bit of hiss with my ear right next to the tweeter. The circuit is based on TubeCad's CCDA topology. I wired in a toggle switch so I can run octal tubes that have either 6.3 volt filaments or 12.6 volt. Right now I'm listening to some NOS Sylvania JAN-12SN7GT's. The JAN stands for Joint-Army-Navy and these have a small US and anchor printed on the base. They are the same tube as the famous 6SN7, only difference is the heater voltage is 12.6 V. Tom send me some RCA 6SN7's he tested so those will go in there next. Here is the money shot with the tubes glowing. I'll try and snap an under the hood shot later.
What would be the best way to go about inlaying a stripe of different wood like that? Dado or router it out then glue in a strip of whatever wood, then plane it even?
Kornbread,
I started with one 4 foot long piece of hickory (5.5" wide). I used my table saw to dado out a 1/2" deep channel down the center. I don't have a dado blade so I made a series of cuts to remove all the material. Then I ripped the mahogany piece until it fit tightly in the channel and sticking out slightly proud. I used a little yellow glue and pounding it in with a rubber hammer. After the glue dried I ran it through my thickness planer.
Comments
My wife and kids are gone this afternoon. Perfect time to take all my measurements
Woohoo! Got everything measured!!! Time to process the files and get after some crossover designs! This (and voicing) is my favorite part of building speakers. So now I have two projects in the works
Well guys I am glad I built these prototypes with cheap wood and spend zero time applying any finish. The six TC9FD's "measured" way better than I expected. Super smooth FR and super low THD. The tweeter measurements were just ok. Woofers were a known (good) going into this project.
I built some prototype xo's based on my XSim and WinPCD work and did a little tweeking. They don't have any glaring issues at all and measure quite well but I was hoping for much much more to my ears.
The sound stage and imaging is no better than the last two way project I did in tradition enclosures
I can't blame the TC9FD's... maybe just too many of them.
As they say "easy come and easy go". My next experiment will be an MTMW with only the M's dipole. Probably the same MCM 55-5670 woofer bass bins, but with two larger mids (5.25" or 6.5") and a traditional 1" dome tweeter.
Could you try it with less of the tc9s hooked up? I know this would require a rework of the crossover but it might be worth a try.
For marketing's sake, the other 4 speakers could be referred to as perceptual drivers
I could try that. I have used the TC9FD's in the past and liked how they sounded, both monopole and dipole.
My gut feeling right now is that I just don't love that (or possibly any) dipole tweeter and how high I have to cross it. It could also be how far away the upper and lower woofers are. Sort of a line array but not really
I've got a nice leftover piece of poplar that I am going to use to make a couple baffles for yet another test project. This time it will be a much simpler MTM, with dipole Peerless 830656 mids and a monopole DA25BG08-06. The weather here is supposed to be pretty decent for January so a few quick trips to the driveway to cut and router the baffles should be doable hopefully. If this one turns out sounding nice it would be a very affordable project with only four $16 mids, two $26 tweeters (I only paid $15 ea), and two $39 woofers (I only paid $26 ea).
I have found dipoles and open baffles to be deceptively complex. They can be really excellent, but there are many variables which take lots of voicing time. They don't seem to be easy to model. For example, I'm still working on my Indiyana entries after 18 months and they are getting close to being done (maybe)...
I hope you don't give up on the basic concept, it seems like a cool idea to me.
By the way, I went with dipole midwoofers and a monopole tweeter
Not sure if you trashed these yet, but in the past I've taped a cardboard enclosure to the back of my dipole to see where my problem was. Flying/ moving the mic around during sweeps also helped. There are a few projects I wished I would have trashed early.
I haven't trashed them yet. Will probably just leave them sit for a while. Maybe circle back when I have some time. They do "look" pretty cool
Ufff... The weather here is making it less and less fun to work outside on speaker projects
Looks like I will be turning my attention back to a 6SN7 tube preamp project I never finished as well as starting a new cigar box class D amp for a friend's desk top system.
Yay! I finished the tube preamp project this morning and have been listening to it for a while today. Wow! I love how it sounds. Zero hum and I can barely hear the tiniest bit of hiss with my ear right next to the tweeter. The circuit is based on TubeCad's CCDA topology. I wired in a toggle switch so I can run octal tubes that have either 6.3 volt filaments or 12.6 volt. Right now I'm listening to some NOS Sylvania JAN-12SN7GT's. The JAN stands for Joint-Army-Navy and these have a small US and anchor printed on the base. They are the same tube as the famous 6SN7, only difference is the heater voltage is 12.6 V. Tom send me some RCA 6SN7's he tested so those will go in there next. Here is the money shot with the tubes glowing. I'll try and snap an under the hood shot later.
I hate you guys ...
I built this CCDA preamp circuit with parts that I had in my junk boxes. It was a proof of concept before ordering top notch parts with the exact values. I wanted to make sure I liked how this circuit topology sounded, make sure it wasn't microphonic, and make sure the preamp gain wasn't rediculously high. I've built numerous preamp circuits that claim lots of amazing things... what I usually find is way too much gain and lots of 2nd order harmonics, or a completely sterile sounding cathode follower with less than unity gain. This project (hardwood case and power supply) was originally a 6V6 tube preamp. That thing was crazy microphonic. This one sounds just right to me and it only has a little gain.
The parts I used are within 20% of ideal values but they are just cheap generic resistors and Audyn Q4 caps. My B+ supply is quite a bit too high (348v vs 300v) so lowering that with my filter circuit will greatly reduce the already low AC ripple.
If you haven't noticed by now... I kind of like building this stuff. Anyway, time to order some nicer parts and upgrade this baby.
TubeCad the diyaudio poster? He really seems to know what NOT to do, and is a funny writer. Seems he's had a lot of experience in the tube area.
InDIYana Event Website
I don't know who that poster is. That diyaudio.com site is a strange place. I am referring to John Broskie.
Checked- I was thinking of Tubelab, not Tubecad.
http://tubelab.com/
InDIYana Event Website
I had to chuckle that a website about tubes is "dedicated to advancing the state of the art"
I don't read it that way. I read it as advancing the state 'of the art (of working with vacuum tubes)'.
He seems really thorough in my limited tube knowledge.
InDIYana Event Website
Read it however you like, I got a chuckle out of it.
Man I really want to built something tubey, maybe some mono blocks, but I need to finish a bunch of other projects first. Right now, it's recapping a Luxman RX102.
Looking great Craig! I found a few different versions of that circuit. Do you have a link to the one you used?
I drew it in Viso. Values in RED are what I used.
So the forward voltage drop of the diode between the grid and cathode is setting bias, correct?
No, it protects the cathode follower triode until the tube warms up.
Don't know if anyone cares, but I always layout how the components will be placed and wired. That determines how many terminal strips I will need and where they will be mounted. Here is what I came up with for this project:
Looks great with those tubes glowing away!
What would be the best way to go about inlaying a stripe of different wood like that? Dado or router it out then glue in a strip of whatever wood, then plane it even?
For that look I would rip one piece and glue an accent piece between the two. If all the board are straight when you start you should get good clean lines when you are done.
Both of the methods you mentioned would work as well. They just require very accurate measurements.
Hi!
Kornbread,
I started with one 4 foot long piece of hickory (5.5" wide). I used my table saw to dado out a 1/2" deep channel down the center. I don't have a dado blade so I made a series of cuts to remove all the material. Then I ripped the mahogany piece until it fit tightly in the channel and sticking out slightly proud. I used a little yellow glue and pounding it in with a rubber hammer. After the glue dried I ran it through my thickness planer.