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Timebomb 
Old Croc
Joined: 11 October 2004
Location: Lancaster
Status: Offline
Points: 2716
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 Posted: 13 December 2013 at 12:56pm |
Look very nice  Are the cabinets MDF? What kind of paint are you using?
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James Secker facebook.com/soundgearuk
James@soundgear.co.uk www.soundgear.co.uk
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ArthurG
Young Croc
Joined: 03 May 2004
Location: France - China
Status: Offline
Points: 976
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Posted: 13 December 2013 at 1:23pm |
 Timebomb wrote:
Look very nice Are the cabinets MDF? What kind of paint are you using?
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Hi Tomebomb  In the first post, I said that the cabinet is 100% made of 17 layers 24mm thick birch plywood. Here's a cut view of it:
For the paint, it's a special formulation for my usage, single component, water borne based (ie washable with water and soap), low VOC, no toxic, no smell, applicable with a roll or a gun machine. I buy it from a US company called Momentive (was Hexion few months ago)
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ArthurG
Young Croc
Joined: 03 May 2004
Location: France - China
Status: Offline
Points: 976
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Posted: 13 December 2013 at 1:36pm |
imageoven wrote:
Hi Arthur,
Nice work. What is the 'function' of the shape around the 6.5"?
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because it looks cool ?  more seriously, the real reason is to physically match the MF and HF phase at the crossover point. In other words, I recess the mid to be able to align it with the HF. The goal is to have a good clean impulse response and keep a flat frequency response out of axis.
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lgosdset
Young Croc
Joined: 28 September 2010
Location: Reading ish
Status: Offline
Points: 1203
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Posted: 13 December 2013 at 1:47pm |
imageoven wrote:
Hi Arthur,
Nice work. What is the 'function' of the shape around the 6.5"?
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yes I am interested by this too. how does this contour around the 6.5 change the sound?
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Timebomb
Old Croc
Joined: 11 October 2004
Location: Lancaster
Status: Offline
Points: 2716
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Posted: 13 December 2013 at 2:42pm |
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I would think it would help reduce diffraction in the mids, as well as look cool.
24mm birch eh, no mucking about, the cut away shows its simpler to build than i first imagined from looking at the finished cab. Is the round over on the mids just cut in steps on the cnc then sanded smooth?
Also, are you using the follow me tool in sketchup to produce the round over or have you found a better way?
Cheers.
James
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James Secker facebook.com/soundgearuk
James@soundgear.co.uk www.soundgear.co.uk
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ArthurG
Young Croc
Joined: 03 May 2004
Location: France - China
Status: Offline
Points: 976
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Posted: 01 January 2014 at 4:28pm |
Hi Timebomb,
sorry the late reply, was very very busy...
For the round around the mid, first I must say that it makes nearly no difference in sound. If I remember, it's less than 0.5dB in frequency response on a very limited bandwidth. The reason is simple, this horn is too small and the expansion is too fast to get any significant loading. Regarding the manufacturing, because I only had 10pcs to do, it's fully made by hand. No tool involved. If I had to make a production of this design, I will make custom guide and bit, but it will still be slow with the hand finish to get a nice smooth surface.
Finally, I got the amp to go with it. After so many months in the bench, tweaking the circuit design, it's nice to see it with a proper casing:
Specs: > Full aluminum chassis with large black anodized heat sink > Dual independent power supply with 300W transformers and 4pcs low ESR 15,000uF caps per channel > Based on TI LME49830 driver and HITACHI 2SK1058 + 2SJ162 MOSFET transitors (3 pairs per channel) > Top class parts including MUSE KZ and custom ASR TWIN-CAP capacitors through signal path > Vintage analog db meters with back illumination by blue LED > Bead blaster front panel with laser engraving > Fully hand made (2pcs manufactured and that's it) > RMS output power per channel at 0.1% THD : 120W 8ohms / 200W 4 ohms > Slew rate : 39V/us > Power supply ripple rejection : 105dB (f=DC) > Typical THD (10W / 1kHz) : 0.0006% > Dimension: W430 x H90 x D300 mm > Weight: 15kg net
Just to clarify an important thing, the "reference" name must be taken literally, ie it's a reference point for me to judge other amps. No way it must be taken "reference" = the best. In this case, "reference" = a reference point for comparison.
Happy new year 2014 to everybody
--Arthur
Edited by ArthurG - 01 January 2014 at 4:30pm
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SMP
Young Croc
Joined: 16 March 2013
Location: East London
Status: Offline
Points: 1226
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Posted: 02 January 2014 at 2:38am |
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There is not much "Tweaking" to do with LME's at all a very simple thing to use as pretty low component count there a lots of Chinese kits for them on ebay using either MOSFET or BJT
But perhaps you would like to comment on your tweaks to the topology?
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SMP
Young Croc
Joined: 16 March 2013
Location: East London
Status: Offline
Points: 1226
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Posted: 02 January 2014 at 2:47am |
 rather much like this one. very little you can do apart from input loading and biasing as it is all in the LME chipset
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ArthurG
Young Croc
Joined: 03 May 2004
Location: France - China
Status: Offline
Points: 976
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Posted: 02 January 2014 at 4:51am |
SMP,
you are not welcome here with your arrogance and your "my stuff is the best, everything else sucks" tone you use in every topic on this forum 
for other people reading this story, I did not use a standard PCB design, my electronic friend engineer did his own, and even if the circuit is very simple and similar to many kits available (basically from a old GOLDMUND Mimesis topology that you can find the schematic everywhere on internet), the difference comes in the parts used. For example, I bought dozen of capacitors to find the tone I like and complementary to REF312. I've tried anything from pure copper foil, pure aluminum foil, silver, even gold from companies like Cicada, Obligato, Clarity cap, Panasonic, Mundorf and Jantzen just to name a few. To be more specific, if you look at the inside picture, you can see 2 big coupling capacitors with yellow epoxy in top left/right corners. These are custom made for me with 2 separate coils connected in series achieving a non-inductive and damping depleted setup. In other places, I've choosen Nichicon Muse Gold KZ and Panasonic special for audio parts. Resistors are DALE high speed non inductive stuff. and so on. The final combination gives the balance between dynamic, details and smoothness I wanted to reach.
As I said, it's not a commercial project and I have nothing to prove. It's only a humble spare time work that I wanted to share with the DIY fellows on this forum 
Cheers, --Arthur
Edited by ArthurG - 02 January 2014 at 4:59am
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SMP
Young Croc
Joined: 16 March 2013
Location: East London
Status: Offline
Points: 1226
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Posted: 02 January 2014 at 5:22am |
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well I merely asked for an explaination of your tweaks. Why you are so defensive and rude I have no idea. but seems any kind of critique is not welcome here unless it is praise of some kind. True I am not a beginner rather a seasoned pro. well whoopie doo you can build a kit!!! and then spend hours or was it weeks to do something simple with it congratulations.
As for my attitude I see no wrong in asking a question or two about it
And just so you can be sure this is a "Forum" which does not mean certain issues or relevant questions should not be asked.
I merely stated it is a very simple circuit that takes minimal effort to achieve as Ti have done it all for you.
Or is it we should just pour praise on anything shown or discussed here regardless?
It seems you are in some way threatened by my apparent knowledge why is that?
Are You not confident enough in your endeavours to deal with any questions about them?
I am more than happy to answer any questions regarding anything I post here I have been doing this for over 40yrs and have gained a vast experience and knowledge of all aspects of Audio, Pro & Domestic.
I reserve the right to judge for myself the validity of any items ideas or principles posted on here. i am far from upset or offended by any critique anyone wishes to post. I feel no way.
IT IS A FORUM. Look it up in a Dictionary to establish it's true meaning.
this is not a place where everyone behaves like Children is it? I thought most on here were Adults. But some seem to think it is an emotive place when clearly it is not. just analytical debate that has place here not a case of "Mummy Mummy that Man was mean to me"
Grow up stop being childish telling me to play nicely or You will take Your Ball back.
Just qualify your "Tweaks" is all that is required & stop throwing your Dummy out of your Pram
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TENSiON
Registered User
Joined: 02 September 2012
Status: Offline
Points: 279
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Posted: 02 January 2014 at 6:30am |
Certainly a nice effort  gotta love a pair of analogue meters and a minimalist approach .. though I must admit I lol'd a bit when I saw those 400V(?) decoupling poly's on the inputs What total gain (input -> output) did you end up choosing?
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ArthurG
Young Croc
Joined: 03 May 2004
Location: France - China
Status: Offline
Points: 976
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Posted: 02 January 2014 at 9:04am |
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When pro audio meets HiFi
