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ray · Post by **ray** » Sat Jan 02, 2010 4:23 pm

Hello everyone and happy new year.

(PS i also posted this on "everyones projects" before i spied the "new users")

I have been dipping in and out of this and other forums for the last year while considering my next project. I have a pretty good idea of what i want to achieve but I am certain that success will be more likely if i take advice. Hopefully a discussion might help others as well. So here i am.

I am building a sound system from scratch starting with the listening room.

Below I have described the room in a little detail because this will be relavant to my questions.

The room is being built as a stand alone annex to the house. There are some requirements beyond the audio properties, namely insulation to keep me warm, windows to let in light etc but i have a faily free hand otherwise. I started with the room dimension ratios based on an 8ft m high ceiling and came up with roughly 20ft x 13ft floor plan which fits nicely into the space available and is just under the maximum area allowable without building regs. I will try to upload a sketch. The building is timber framed with 200mm of insulation. The walls at the speaker end will be lined with plasterboard with 2inches of packed sand behind.
The back wall and corners will have a fabric covering a 2" gap then some heavy mineral felt then 9" of insulation. The outer skin will be 3/4" Oriented strand board 2" gap then shiplap cladding on the outside.
The side walls will be tongue and groove pine with doors in the middle. I want to place the doors where the first reflection point is: in the summer i can open them to let the reflections out and in the winter i can cover them with heavy drapes.
The cieling still needs some thought but i think i will have an opening into the loft space where the first reflection point is. This will form a mezzanine at each end of the room and hopefully will function in the same way as the doors. I can also crawl up there and sleep!

So hear come the questions:

Q1) My first choice of speaker is the Fostex Sachiko horns. I need to choose between the 206e full range drivers or the 208 sigma with the tweeters. Advise on this point would be much appreciated (Moose?).
Q2) This is the biggy. Which amp!! I want to build a valve amp from scratch. I guess these speakers are pretty efficient and its not that big a room (though i do like to crank it up at times!).

Advice on these point would be very much appreciated.
I have some knowledge of electronics, i have dabbled with valves and i was once (in a previuos life) a prototype wireman. I like Jazz and Rock particularly but pretty eclectic really, the odd string quartet and oh yes, female vocals.

Best wishes to all
Ray

PS cant find the sketch of the room...next post!

Post by **Nick** » Sat Jan 02, 2010 4:29 pm

Just a thought, can you make the walls not parallel?

ray · Post by **ray** » Sat Jan 02, 2010 4:50 pm

I am building this at "my place of work" and i do have to "hand it back" one day, so probably non parrallell walls would not get past the owner! (its a complicated story / set up) Doesnt fit with my KISS principle either...

Been searching for the well tried rocky amp you mentioned....no luck yet, can you point me please?

Cheers
Ray

Mike H · Post by **Mike H** » Sat Jan 02, 2010 4:53 pm

Nick wrote:Just a thought, can you make the walls not parallel?

First thing that occurred to me too!

Plus a sloping ceiling might be good.

Many years ago there was an Australian guy made a special hi-fi room extension, there was a hi-fi mag article about it. IIRC it had a infinite baffle type single bass speaker built into the wall at one end and I'm pretty sure the walls / ceiling / floor weren't parallel either

Failing that, loads of thick curtains over the walls

.

ray · Post by **ray** » Sat Jan 02, 2010 4:54 pm

PS i might have caused confusion by posting in 2 places. so i will continue this on eveyones project forum...

thanks guys
Ray

Mike H · Post by **Mike H** » Sat Jan 02, 2010 4:55 pm

ray wrote:Been searching for the well tried rocky amp you mentioned....no luck yet, can you point me please?

Cheers
Ray

Go to top of page, click 'Search', type 'rocky', Enter

.

shane · Post by **shane** » Sat Jan 02, 2010 7:51 pm

Now you come to mention it Ray, I've seen innumerable references to Rocky amps on here and the assumption is always that the reader and poster both know what they are talking about, but I can't recall ever seeing a basic description.

Anyone?

Scottmoose · Post by **Scottmoose** » Sat Jan 02, 2010 8:33 pm

Well, I don't hold with fancy commercial wire, but George Cardas's room design advice is worth following if you can: http://www.cardas.com/pdf/roomsetup.pdf

Re the speakers, I'd personally go with the 208ESigma + supertweeter. Needs a minimum listening distance of 8ft & keep them away from corners. Avoid MDF like the plague.

Can't really speak for amps, me, I like Nelson Pass's Class A single gain-stage SS amps, but I'm in a minority, and other people here (everyone) is far better qualified to talk about amplifiers than I am. From my POV, make sure the power supply is as stiff as possible, and you'll need good transformers.

Mike H · Post by **Mike H** » Sat Jan 02, 2010 10:27 pm

shane wrote:Now you come to mention it Ray, I've seen innumerable references to Rocky amps on here and the assumption is always that the reader and poster both know what they are talking about, but I can't recall ever seeing a basic description.

Anyone?

Yes the universal starting point and reference is this:

http://angela.com/stereosingle-endedel3 ... ifier.aspx

.

al newall · Post by **al newall** » Sat Jan 02, 2010 10:30 pm

Ray.

There are a few versions of the "Rocky" amp.
This is the only schematic i have left, but it's a good place to start.
Someone would need to help you with a supply for it.

Mike H · Post by **Mike H** » Sat Jan 02, 2010 10:45 pm

Yes, who was it made it more or less as per the Angela circuit?

I.e. not modifying it like the rest of us

Little Eddy?

.

colin.hepburn · Post by **colin.hepburn** » Sat Jan 02, 2010 11:03 pm

Hi Ray
Here the The Rocky amp psu Sch for a fuller discretion on the rocky amp maybe best to PM Steve the shadow as he,s the chap that put together the posted Schematics and built the amp that some of us are now building

as rocky 3 and beyond

Mike H · Post by **Mike H** » Sat Jan 02, 2010 11:20 pm

Yes that's it, doesn't have to be too elaborate.

.

Mike H · Post by **Mike H** » Sun Jan 03, 2010 12:37 am

Meant to mention, ta Scottmoose for the PDF looks well handy.

Not that it helps me a lot in my present situation but I did pick up on a couple of bits that seemed familiar only insofar that I'd already had to resort to similar purely by experimentation.

I like the bit about having a vent into the loft at the listening end

.

Dave the bass · Post by **Dave the bass** » Sun Jan 03, 2010 8:55 am

Hello Ray, welcome.

DTB

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