audio-talk

[Toppsy]

For all those that enthrallingly followed the Sachiko build in the later stages of the thread, will no doubt have noticed the mention of these speakers and I believe, Martin posted some result plots of this very design there.

Well I managed to persuade a copy of the plans out of Martin with a view to build a pair, and with his permission post a running commentry (with pictures) of the actual build here on our little forum, for all to follow.

Well I have made a start on the build. All the ply is cut to size and all openings routed out - all 2 of them Material for these relative small floor mounted back loaded horns is from 18mm Russian Birch Ply main carcass with 12mm internal baffles and bracing. I have posted the first of my photos below which show just how few panels are required for one speaker. Just twelve panels in all - 6 in 18mm ply and 6 in 12mm ply. Simple as the Merecats would say.

I wont say more about the design as I feel Martin himself should part with this information should he wish to, as the plans are not in the public domain as yet. Well, to the best of my knowledge they are posted on his web site

As mentioned the drivers are the Mark Audio Alpair 10. These are a 6" full range driver of around 87dB efficiency with a 100mm thin-wall alloy cone either in gold or gray. I have ordered some gold ones.

More tomorrow. For now here are the photos:

[simon]

Looking forward to hearing these Colin, and fair play to Martin for sharing the plans.

[steve s]

I'll second simons comments and to add that scott is very impressed with this driver.. can't wait until sept? to hear them colin,,

cheers
steve

[andrew Ivimey]

87dB is a bit insensitive though, isn't it!

anyway, onwards! Colin - get them nails and glue going.

[Nick]

[Andrew]

87db, more steam, we need more steam...

[Toppsy]

Nick,

I was thinking the 300b amp I hope to have ready (with your help) for Owston would be man enough for these speakers

I should have mentioned in my original posting that I have enough ply computer cut to make 2-pairs of these speakers. I also have on order 2-pair of the drivers.

So if anyone else fancies building a pair these get in touch by pm and with the consent of Martin King of my releasing the plans I'm sure we can come to some agreement over the cut ply and the spare set of drivers.

Another interesting take on these drivers is DaveD of Planet 10 has been getting very positive results when modifying them with his ENABLing especially the CHR70 drivers which in stock form are as cheap as chips.

[Nick]

Well, a 300b will drive them, but it wont go loud, especially with TJ mesh plates. 87dB/W seems low by most of the standards we use around here.

[Toppsy]

OK, We'll have to save the 300b for the Fonkens that the amp was originally intended and I'll have to go to weight training sessions and haul out the gm70 monoblocs again

[Andrew]

more steam, push pull 300B interstage coupled or....borrow Max's 211

[Nick]

Yep, they would do the job

[pre65]

I thought Colin was building an 807 PP amp ?

That would do.

[Toppsy]

Phil,
I was building a pp 807 amp but it then got canibalised for the direct drive electrostatic amp build at eggfest. I wont get my bits back until Ali and Nick get the right sort of ironwork for the final incarnation build of that amp. Not that I'm in a rush to progress this as my funds were then and still are a little low for buying some decent TX's etc to finish this off proper.

Nick has offered me the loan of the TX's etc for the 300b amp build which will be a replica his recent 5687/300b monoblocs he previewed at Simon's birthday bash earlier this year. I have the tubes, I just need to buy some caps, resistors and valve bases which I am tracking down from the list of components Nick gave me on the original build.

[planet10]

[Ali Tait]

Colin I still have an original WAD 300b PP you are welcome to borrow if you like..