Hi Andy,
I have a Tony Wong 8 watt 300B SET amp as my primary demo unit in my large 1200 square feet studio. This amp is currently operating all demo drivers including Alp12's in Pencil 12 boxes. For the Alpair 10's I'm using a 14 litre vented box for testing, Tony's amp easily driving this set-up with no problems.
Not sure of your 300B configuration. I'm no expert on amps but I'd expect most 300B's around the 8 watt+ region to handle Alpairs with reasonable ease in most room environments. I like 300B's allot, but I'm also a fan of 2A3 having used Brian Cherry's Joplin (7 watt DHT) amp in my early days.
You sure the input gain is sufficient? Or, is your 300B a lower output design?
Thanks
Mark.
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Do you still have the Joplin, or at least memorable enough listening impressions to voice on opinion of the merits of a 2A3 P/P? Too bad Brian discontinued this model - not to disrespect any of the number of current and "affordable" 300B SE product / kits - there are tons of them out there (I've owned or extensively listened to a few myself) - but very few designs like the Joplin was.
Mark and Chris - that's good to know. So 8w of 300b should be fine. By the same reckoning a 2a3 PP amp at book operating points should be 7w. Looks like my 300b output is too low - doesn't surprise me with the cool operating point I have, plus tubes may be old. I'll have to look at it again. I've built most of a 2a3 PP amp, so it'll be interesting to compare them.
Andy
Andy
Hi Chris
Actually, I have 2 Joplins. One integrated (basic model), the other converted to power and mated to the Django but I couldn't get this combo to work well together. Both Joplins were "entry level", I hadn't got enough money at the time to buy Brian's upgrades. Even so they're nice amps, doing good work with Alpair 10's.
Cheers
Mark
Hi Andy,
Here's 2 pics of my Tony Wong 300B I use at home. The valve (tube) combination of this amp work well (Full Music 300B's, Full Music 6SN7, Japanese Vintage rectifier and Russian 6SN7's on left/right channels. The valves are getting a bit tired as we use this amp around 8 hours a day on average. We run all audio through this amp (local and cable TV, CD, DVD, etc.,)
7 watts of 2A3, should also be nice for the Alps.
Cheers
Mark.
Attachments
Final tuning
Aloha; i am back
Well, the alpairs are far beyond break in point now, so i decided to do the final tuning.
When listening to music, all seems fine
I stuffed the enclosure whit sonofil from top till right under the alpairs.
Looked like it would work well.
Experimented a bit, and at a certain point i decidet: this is ok
So, the other night me gf and i where watching a movie, and i said: lets turn on the alpairs to enjoy their sound with this movie
Now...something strange happened: it still sounds a bit like there is some reflection or something like that.
Mostly voices are soundning like they are reflected...its just a litle bit, but it starts ton anoy the candy out of me and me gf.
Anyway, i already camfert the back side of the bafle whit a file, almost 45degrees.
So i guess thats not where the reflection s are comming from.
In total dispair i decided to ad birumen behind the driver....no improvement at all,.
Could this be related to the units not being totally artight in the enclosures?
Dont dare to put more torque on the screws.....the camfering made the flesh for the srews fery small.
Pardon my bad english, lol
Well, i sure hope u guess can help me on working on this final problem, would realy be apreciated
Aloha; i am back
Well, the alpairs are far beyond break in point now, so i decided to do the final tuning.
When listening to music, all seems fine
I stuffed the enclosure whit sonofil from top till right under the alpairs.
Looked like it would work well.
Experimented a bit, and at a certain point i decidet: this is ok
So, the other night me gf and i where watching a movie, and i said: lets turn on the alpairs to enjoy their sound with this movie
Now...something strange happened: it still sounds a bit like there is some reflection or something like that.
Mostly voices are soundning like they are reflected...its just a litle bit, but it starts ton anoy the candy out of me and me gf.
Anyway, i already camfert the back side of the bafle whit a file, almost 45degrees.
So i guess thats not where the reflection s are comming from.
In total dispair i decided to ad birumen behind the driver....no improvement at all,.
Could this be related to the units not being totally artight in the enclosures?
Dont dare to put more torque on the screws.....the camfering made the flesh for the srews fery small.
Pardon my bad english, lol
Well, i sure hope u guess can help me on working on this final problem, would realy be apreciated
Are you absolutely sure it's the speakers? Seems kind of strange that music sounds fine but not movies. Both speakers have the same problem? I just always check the obvious stuff first and try to isolate the problem by swapping wires, speakers, whatever. Maybe you already have. Good luck I'm sure you'll find it.
ok, i am back...again..
I removed the speaker srews and used nuts and bolts.
Checked lining, all looked fine enclosure is airtight.
Changed the amount of sonofill behind the speaker...removed some.
Hooked it al up again.
So far, the radio is a logitech squeezebox classic, still sounds a litle reflective, could this be bitrate related?
Some rippd movies also still sound a bit reflective....
I also tryed a dvd....same result, but not that forward.
How did i hook it up:
Squeezebox>dac>line in pre amp.
TV> analogue out> line in pre amp.
Media player> hdmi out>hdmi in tv>line in pre amp
Maybe its in the digital domain.
My media player is a asrock ion 330 bd its running XBMC.
I removed the speaker srews and used nuts and bolts.
Checked lining, all looked fine enclosure is airtight.
Changed the amount of sonofill behind the speaker...removed some.
Hooked it al up again.
So far, the radio is a logitech squeezebox classic, still sounds a litle reflective, could this be bitrate related?
Some rippd movies also still sound a bit reflective....
I also tryed a dvd....same result, but not that forward.
How did i hook it up:
Squeezebox>dac>line in pre amp.
TV> analogue out> line in pre amp.
Media player> hdmi out>hdmi in tv>line in pre amp
Maybe its in the digital domain.
My media player is a asrock ion 330 bd its running XBMC.
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ok, just did a test, played movies using another mediaplayer..
Sounds realy fine
Problem seems to be in the downmix from 5.1 to stereo, so, now i am fidling the settings of xbmc
And regarding the squeezebox radio>>>bitrate related...what a bummer.
Good news: this is a good excuse to buy a vintage tuner
More good news: my gf would like a beamer in the bedroom...jihah!!
This calls for a new project:
A all alpair 2.1 sound system!!!
Enclosures must be small, so i think the alpair 5/6/7 would be nice
I wanna top it off with a woofer, wanna build the amp in the subwoofer, so also looking for a 2.1 plate amp.
Finally...more wood in the shop to cut"
Ill open a new topic and keep u all posted
Thanks for all the help here...realy apreciate it.
Sounds realy fine
Problem seems to be in the downmix from 5.1 to stereo, so, now i am fidling the settings of xbmc
And regarding the squeezebox radio>>>bitrate related...what a bummer.
Good news: this is a good excuse to buy a vintage tuner
More good news: my gf would like a beamer in the bedroom...jihah!!
This calls for a new project:
A all alpair 2.1 sound system!!!
Enclosures must be small, so i think the alpair 5/6/7 would be nice
I wanna top it off with a woofer, wanna build the amp in the subwoofer, so also looking for a 2.1 plate amp.
Finally...more wood in the shop to cut
"Ill open a new topic and keep u all posted
Thanks for all the help here...realy apreciate it.
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Cylindrical (PVC pipe) MLTL based on Jim Griffin's design
Hi, I am planning my first foray into DIY speakers (many years of DIY electronincs). I am hopeless at cabinetry. I am interested in approximating Jim's MLTL for the Alpair 10.2 using 6" PVC. I would use a Tee to mount the driver (sawed off as close to the column as possible), with PVC above and below, caps on both ends, and 2" PVC for the port.
The cross-section for this pipe is 28.26 square inches, as opposed to 31.5 for Jim's design. My question is should I lengthen the tube to more closely approximate the total volume of the original? Change the port?
The original's volume is 0.83 cu ft. I would need to extend my total length to 50.7 inches to equal the volume. If I did, would I move the port higher? I presume I still want the driver about 1/3 from the top.
Any thoughts would be greatly appreciated. One advantage to using this pipe is that until it's glued, dimensional changes are fairly easy.
Jack
Hi, I am planning my first foray into DIY speakers (many years of DIY electronincs). I am hopeless at cabinetry. I am interested in approximating Jim's MLTL for the Alpair 10.2 using 6" PVC. I would use a Tee to mount the driver (sawed off as close to the column as possible), with PVC above and below, caps on both ends, and 2" PVC for the port.
The cross-section for this pipe is 28.26 square inches, as opposed to 31.5 for Jim's design. My question is should I lengthen the tube to more closely approximate the total volume of the original? Change the port?
The original's volume is 0.83 cu ft. I would need to extend my total length to 50.7 inches to equal the volume. If I did, would I move the port higher? I presume I still want the driver about 1/3 from the top.
Any thoughts would be greatly appreciated. One advantage to using this pipe is that until it's glued, dimensional changes are fairly easy.
Jack
Brilliant idea - I'd also be interested since I use an Alpair 10. I'm thinking a better idea would be a pipe within a pipe, with something like sand in between. Or even a concrete pipe.
A simple idea for an omnidirectional loudspeaker would be the following or a variation on it. Never heard of an upward firing Alpair 10 yet.
Pluto construction
I'm in the UK and was looking at this range of products for piping - some interesting bits.
http://www.eurotradeplastics.co.uk/pdf/1_Underground_Drain.pdf
Andy
A simple idea for an omnidirectional loudspeaker would be the following or a variation on it. Never heard of an upward firing Alpair 10 yet.
Pluto construction
I'm in the UK and was looking at this range of products for piping - some interesting bits.
http://www.eurotradeplastics.co.uk/pdf/1_Underground_Drain.pdf
Andy
For a bass reflex or closed box, adjusting the length to keep the same volume is ok. In an MLTL the length does play a role however. It should need to be remodeled in mathcad to decide on the influence. Now since the cross area is 10% different, I expect you will still get ok results without lengthening the tube.
Hey, thanks for all the quick replies.
Andy, the 160 mm pipe at your supplier would be a little larger and closer to the cross section of Jim Griffins box. I am definitely using the 6" PVC because I found a local guy with LOTS of scape pipe he wants to get rid of, and who also has a band saw he will use to cut it for me if I take it off his hands.
Tlaerts and GM, thanks, I should probably keep the height the same and use more stuffing than in the original. I am actually going to take a crack at MathCad modeling and have ordered Martin King's TL models. Wish me luck in using these!
GM, I am going to try to get the driver mounted with as much of it as possible inside the vertical tube, by cutting off much of the arm of the Tee in which it is mounted. Obviously, getting the driver mounted is going to be the trickiest part of the construction.
Jack
Andy, the 160 mm pipe at your supplier would be a little larger and closer to the cross section of Jim Griffins box. I am definitely using the 6" PVC because I found a local guy with LOTS of scape pipe he wants to get rid of, and who also has a band saw he will use to cut it for me if I take it off his hands.
Tlaerts and GM, thanks, I should probably keep the height the same and use more stuffing than in the original. I am actually going to take a crack at MathCad modeling and have ordered Martin King's TL models. Wish me luck in using these!
GM, I am going to try to get the driver mounted with as much of it as possible inside the vertical tube, by cutting off much of the arm of the Tee in which it is mounted. Obviously, getting the driver mounted is going to be the trickiest part of the construction.
Jack
I have downloaded Malcolm King's worksheet for MLDL and have been playing around with it. Incredible, as you all know. Lengthening the tube beyond the orignal design actually should improve low-frequency performance with my reduced cross-sectional area, but the port appears to need lengthening as well, as well as increased stuffing density.
This model assume a rectangular cross-section and a horizontal port. I am obviously using a circular cross-section and would like to use a vertical port. Does anyone know whether this matters with regard to the output of this model?
Thanks for all your help, Jack
This model assume a rectangular cross-section and a horizontal port. I am obviously using a circular cross-section and would like to use a vertical port. Does anyone know whether this matters with regard to the output of this model?
Thanks for all your help, Jack
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