DIY thoughts of the day

A place for DIY project discussions.
User avatar
karatestu
Posts: 3011
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Has thanked: 85 times
Been thanked: 63 times
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu »

Best wishes to you all. Fret, my heart goes out to you. I hope you and your father find strength.
These users thanked the author karatestu for the post (total 3):
Fretless (Fri Apr 17, 2020 6:56 am) • slinger (Fri Apr 17, 2020 1:55 pm) • savvypaul (Fri Apr 17, 2020 2:09 pm)
DIY inspired by Richard "The Doc" Dunn RIP

valvesRus
Posts: 383
Joined: Sat Feb 24, 2018 2:34 pm
Has thanked: 6 times
Been thanked: 2 times
Great Britain

Re: DIY thoughts of the day

Unread post by valvesRus »

Fretless wrote:
Thu Apr 16, 2020 11:25 pm

Stu, don't bother with hifi - you have more important things to concern you.
Fair point, but sometimes we need a diversion from the bad/sad things in our life.

For me, DIY hi-fi took off in 2006 after my dear wife died, and it really helped me. I don't do much these days but I know I can if the need arises.

User avatar
slinger
Posts: 5272
Joined: Wed Aug 22, 2012 4:30 pm
Location: The Garden of England
Has thanked: 251 times
Been thanked: 263 times
Great Britain

Re: DIY thoughts of the day

Unread post by slinger »

I think I know what valvesRus is saying, and as long as we remember that it is a diversion and not a substitute for, or a solution to, any real shit that's happening it's a good thought.
Amps - NVA P50, A30, A40, Stanislav Palo Tube Headphone Amp BB 85
Speakers - Monitor Audio Silver RX2
Cables - NVA LS1+LS3, SSC, Gotham S/PDIF, IBRA Optical
Digital - NAD C516BEE, SONY ST-SDB900 DAB TUNER, TEAC UD-H01 DAC
Analogue - Pro-Ject Debut Carbon Esprit SB, Graham Slee Gram Amp 2 Phono
Cans - Grado SR80, ATH-M50X

User avatar
karatestu
Posts: 3011
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Has thanked: 85 times
Been thanked: 63 times
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu »

Been looking more closely at transmission line speakers. It's a different world to closed box design and more complicated. The length of the line, area of line, degree of taper (if it is quarter wave tapered), area of mouth, area of terminal vent (if vented), volume of line, amount and positioning of stuffing, placement of driver along the line all adds up to the final design.

I rediscovered my little B&W P4's very recently and they are a tapered quarter wave design with forward firing vent and use a 6.5" kevlar mid bass along with a 1" metal dome. The dreaded xover is a single inductor for the low pass filter and a more complicated two capacitor + inductor T with a 1R5 padding resistor for the tweeter high pass filter.

You can't just throw in a doped 6.5" qtx driver as the TS parameters are bound to be different. Doping the existing kevlar driver will lower it's resonant frequency maybe not too much as to change the workings of the tapered quarter wave pipe. Putting a single capacitor on the tweeter would probably not be a good idea without the xover frequency being higher (which it likely would be if the inductor was removed and the mid bass doped.

The thing is I have a bit of a dislike for metal dome tweeters. , i prefer something a bit more relaxed like the Visaton soft domes. A G20sc won't fit in the hole as the original tweeter has a neo magnet and is tiny in comparison. So a bit of wood work is required to do that.

Add more tweeters -yes.........that is the answer to everything :grin: Got to be done. Another three firing up, in & out.

Make a hole in the top to make it semi omni ? Not a bad theory but the drivers position along the line changes a wee bit.

Keep the mid bass firing forward and add another up firing ? Put one in both sides as well. That will muck up the design of the line as when you add more drivers the volume of the box should increase and the area of the line also. Maybe i need to make an identical pair of enclosures and try all this stuff out at which point i can say the mods are all crap and the original was best :lol:

Last idea (honest). As the enclosure is only 81 cm tall, how about adding another little box (sealed) on top off it housing one of the little 5.25 " doped units. That doesn't mess the bass response of the line up and adds a bit of semi omniness. Four tweeters firing forward, up, and to both sides and Bob's ya uncle (maybe :pray: ).
These users thanked the author karatestu for the post:
Ithilstone (Sat Jun 20, 2020 7:05 pm)
DIY inspired by Richard "The Doc" Dunn RIP

User avatar
Ithilstone
Posts: 506
Joined: Mon Jun 01, 2015 10:54 am
Has thanked: 13 times
Been thanked: 18 times
Seychelles

Re: DIY thoughts of the day

Unread post by Ithilstone »

karatestu wrote:
Sat Jun 20, 2020 6:37 pm
Been looking more closely at transmission line speakers. It's a different world to closed box design and more complicated. The length of the line, area of line, degree of taper (if it is quarter wave tapered), area of mouth, area of terminal vent (if vented), volume of line, amount and positioning of stuffing, placement of driver along the line all adds up to the final design.



Last idea (honest). As the enclosure is only 81 cm tall, how about adding another little box (sealed) on top off it housing one of the little 5.25 " doped units. That doesn't mess the bass response of the line up and adds a bit of semi omniness. Four tweeters firing forward, up, and to both sides and Bob's ya uncle (maybe :pray: ).
Like the last idea the most ;]
Nothing to see here...

User avatar
karatestu
Posts: 3011
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Has thanked: 85 times
Been thanked: 63 times
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu »

Ithilstone wrote:
Sat Jun 20, 2020 7:05 pm

Like the last idea the most ;]
Me too :guiness;

With a little 5.25" there is room for an upfiring tweeter as well :dance: Happy days. It won't be possible to do a cube for the added cab due to the existing dimensions of the P4's. It only needs to be about four litres internal volume so won't make the whole thing too tall.
DIY inspired by Richard "The Doc" Dunn RIP

User avatar
karatestu
Posts: 3011
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Has thanked: 85 times
Been thanked: 63 times
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu »

Went to pick up something free from a local pfm'er. A 1990's lighting psu from York University.

It has a couple of EI frame transformers in it. One is absolutely massive I have never seen a transformer that big. The thing weighs a ton. Also some 22,000 uf and 10,000 uf 63V BHC capacitors andvarious other goodies. I don't have an ESR meter so don't know if the caps are any good. The unit outputs 48V so could be good for an amplifier :dance:

Whilst I was there I had a quick listen to his system and a cup of tea. Linn Isobariks on the end of a full Linn system including LP12 and two racks full of goodies. Was rather good I thought (no laughing at the back please) but the up firing tweeter and mid had been removed which seems to be going in the opposite direction to my speaker development where more and more seem to be getting added :lol:
DIY inspired by Richard "The Doc" Dunn RIP

User avatar
karatestu
Posts: 3011
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Has thanked: 85 times
Been thanked: 63 times
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu »

Can't be arsed with hifi - now I just listen to / watch random shite on youtube through the telly.
DIY inspired by Richard "The Doc" Dunn RIP

User avatar
savvypaul
Posts: 4994
Joined: Tue Oct 11, 2016 7:14 pm
Location: Durham
Has thanked: 260 times
Been thanked: 219 times
Contact:
Great Britain

Re: DIY thoughts of the day

Unread post by savvypaul »

YouTube is good fun...I love getting lost in it
Amplification - NVA P90SA / A70s & A60
Analogue - BTE Designs Lenco L59 / Garrard 401 / Ortofon TA-210 / Jelco 750L / Audio Technica ATP 12T / Ortofon SPU / Denon 103 / NVA Phono 2
Digital - Sonore MicroRendu / RME DAC-2
Speakers - NVA Cube 1 / Klipsch Heresy 3

“The one who would whistle to, Throbbing Gristle through, harsh times in Umberstone Covert”

User avatar
slinger
Posts: 5272
Joined: Wed Aug 22, 2012 4:30 pm
Location: The Garden of England
Has thanked: 251 times
Been thanked: 263 times
Great Britain

Re: DIY thoughts of the day

Unread post by slinger »

savvypaul wrote:
Fri Jul 03, 2020 8:22 pm
YouTube is good fun...I love getting lost in it
Same here. I love going "down the rabbit hole" on YouTube, jumping from suggestion to suggestion until I've lost track of what I was actually searching for. I find some great stuff that way.
These users thanked the author slinger for the post:
savvypaul (Sat Jul 04, 2020 4:06 pm)
Amps - NVA P50, A30, A40, Stanislav Palo Tube Headphone Amp BB 85
Speakers - Monitor Audio Silver RX2
Cables - NVA LS1+LS3, SSC, Gotham S/PDIF, IBRA Optical
Digital - NAD C516BEE, SONY ST-SDB900 DAB TUNER, TEAC UD-H01 DAC
Analogue - Pro-Ject Debut Carbon Esprit SB, Graham Slee Gram Amp 2 Phono
Cans - Grado SR80, ATH-M50X

Post Reply