DIY Audio Projects Forum

Hi, They will probably not respond. Send me a PM.

Good listening
Bruce

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Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

I didn't go into LDC7 too complicated yet, just entered the manufacturer's parameter settings and played with the box dimensions. For me working with imperial measurements is interesting having had to move to metric in the 60s. Good to practice the conversions though. Might help to delay dementia. .

Appreciation to Bruce for assistance with LDC7.

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John

This driver works extremely well in a 60ltr ported box with their suggested port. And is cheap.

https://www.visaton.de/en/products/full ... g-20-8-ohm

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

I did see this driver in my browsing and it does look good. I was aiming for a 5 or 6.5 inch driver and in the end went for a 6.5 ps180 Dayton audio which I estimate is 150-160cm diam. It looks quite nice and the few reviews of it I found are quite positive. It will bass shy. Still trying to settle on a box design. I have drawn up a possible design based on diyaudio.com members scottmoose and planet10s "Stinger" which I think was designed for an Alpair 6 or 7. I have some other options from the above bass reflex simulations. I had a dabble with hornresponse and Lenard audio transmission line simulations and posted results for comments but difficult to be noticed I guess or what I am doing is way off and naive. It's a bit of a learning curve. I am not expecting great bass response from a small fullrange. In the music I mostly listen to this shouldn't be a problem. If I put on a cd of orgel music from the cathedral of St. John the Devine I know what to expect. The vistatons however may be a future project maybe in the 125-130cm, 5". They seem good value and may go well with a small subwoofer. There seems to be lots of competition in the 100-125cm, 4-5" range.

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John

He is my Mark Audio 12P build . I used their pencil tower design, the deeper one. I get 40hZ in room. And they test out to 20K. Very happy with the speaker.

http://retro-thermionic.blogspot.com/2018/08/voxuno-12p-with-markaudio-drivers.html

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

Thanks Mark. Yes for some time I have admired your speakers. They're a good size. As I am looking to downsize in the not too distant future I am aiming for around the 16-20 litre mark. I may have to choose between these and my current two way commercial speakers too to keep things peaceful. I read good things about the markaudio range.

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John

I started the build proper. Not really but won't be long. I ordered the wood from a local plywood and panel place. I intended to use plywood but the company steered me away from the more reasonably priced hardwood to Russian birch. I couldn't justify the cost so mdf it is.

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John

Nothing wrong with MDF. It sands and paints well.

I use a roller to create a stipple finish. Only applying one wet coat over both boxes then come back WITH NO MORE PAINT five more times with a semi-dry roller to “tease” up the drying paint. For the dryer rolling only roll in one direction. Use only a high quality paint. This is called the much talked about Houston finish.

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

That’s good to hear. The Houston Stipple may become a new trend.

I should start a new thread which I will do once I get drill and glue in hand because I moved away from the ported box enclosure to a transmission line or acoustic labyrinth. My inspiration was from a group of posts on diyaudio.com in the fullrange area. I was going to go for a similar style as the Lance enclosure but decided on the Stinger, attached. This was designed for a smaller driver so I tried to optimise the size for my larger driver while constraining size as much as I dare.

I changed the offset of the driver mainly to have it centrally located on the front baffle potentially at the cost of unwanted resonance. My much less attractive drawing is also attached. I used Inkscape and am still navigating how to apply dimensions. All up it will be around 18L. the external dimension are 236x306x315. the taper of the labyrinth (i modelled quite a few) starts at 250cm^2 to 40cm^2 at the terminus. If they sound ok I will exclusively use this with the 6sn7/300b tube amp. Currently i switch a pair of b&w 706s2 two ways between the tube amp and the class d theatre amp for movies etc.

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John

Finally devoted a day to putting hole in my pristine MDF panels following several trips to bunnings, boltbiz, and jaycar compiling the parts needed. I’ve still got another trip to jay car to buy some crimp connections I forgot. Some shots attached.

I found i needed to mark out on the panels where screws and panels should be located. then I started drilling pilot holes. I will eventually counter sink the 40mm 8 gauge screws but I just did a bit of a mock up (no glue yet) to see how everything fits.

for the speaker and plastic binding posts i thought i would try 4mm threaded 25 mm captive t nuts. I should get some loktite to be sure.

I’ll put the top on and one of the remaining partitions and wire up the speaker tomorrow. I may have to experiment with the amount of poly fill as there doesn’t seem to be hard and fast rules. The tline model assumes medium stuffing in the first and second sections and none or light in the third. As to what medium and light mean for the actual weight of poly fill I don’t know. more research planned.

The other speaker will have to wait for a week or two as i’m back to work thursday but I’ll try and get an hour in here and there to avoid a protracted build.

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John