DIY thoughts of the day

A place for DIY project discussions.
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karatestu
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Re: DIY thoughts of the day

Unread post by karatestu » Sat Aug 31, 2019 2:01 pm

I am done with spending money with this diy lark. Spent far too much over the years. From now on i am just using the parts i already have, which is quite a lot :dance: . The surplus i will try and sell.

Phono stage is a Phono1. That is getting pulled apart with amp board and regs in a metal enclosure either in the TT or as close behind as i can. Very short arm lead if i do it that way. Think Naim prefix but better :grin: . PSU for that will be remote and consist of four 100VA EI transformers, MBR20200CT rectifier diodes and some kendeil 6,800uf caps. The last smoothing cap will be just before the regulators.

Speaking of regulators, there is only one positive and one negative reg in a Phono1. I need another three pairs which i will have to fabricate myself out of parts i already have knocking about. Doc's reg is extremely simple and i have the necessary parts already.

There will be six power amps using NVA boards (unless i blow one up) and i am giving all of them 2 psu's each like the A80 and A100 designs. So twelve psu's in all for the power amps (bloody hell) :o . In order to use up what i already have i will have to use four transformers with secondary voltages that are too high so some regulators are needed to drop the voltage a bit. They will be used on the front ends of the bass and mid frequency amps.

The tweeter amps will get two very nice 100VA EI frame transformers with twin centre tapped secondary windings. No regulators on these as the voltages are low enough to be used as is. All power amp psu's are going to be remote as well.

As for speakers, well i change my mind every day. As i dont intend buying owt else then my plan for BBCube style speakers with three isobaric 12 inchers, three 5" mids and three tweeters is not going to happen. I am going to have to make do :violin: with two isobaric 12 inchers, one 5" mid and one tweeter. Two bass drivers either down firing or one down firing and outer one front firing, one up firing mid and the tweeter front firing as usual.
DIY inspired by Richard "The Doc" Dunn RIP

montechristo358
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Re: DIY thoughts of the day

Unread post by montechristo358 » Sat Aug 31, 2019 3:00 pm

2 PSUs for each Amp, how does that connect up then?

Any benefit over using 1 PSU twice the size or just using up stuff thats available

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karatestu
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Re: DIY thoughts of the day

Unread post by karatestu » Sat Aug 31, 2019 3:16 pm

It sounds better (IMO). The psu on front end duties is not subject to the voltage sag and ripple caused by the heavy load on the output stage.

As for connecting them up - the front end is isolated from the output stage on the amp board pcb. The two psu's have to have their 0V connected at some point. The hard part is finding out where the best place to do that is.
DIY inspired by Richard "The Doc" Dunn RIP

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karatestu
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Re: DIY thoughts of the day

Unread post by karatestu » Sun Sep 01, 2019 6:57 am

A thread on another forum reminded me of the experiments i did with moving my speaker crossovers (B&W P4 that are in retirement) from the speaker cabinet to directly behind the amplifier. I had about 6 inches of wire from amplifier board to the filters. I could not believe the improvement it brought. Nobody on the forum could come up with a technical reason why it should make any difference at all but it did and several very well respected members reported the same.

Of course the idea was poo pooed but i wasn't the last member there to try it and imagine the improvements :grin: . Anybody who is curious about it then give it a go. You need another set of speaker cables though or the biwire option for nva amps to keep capacitance low. Just don't get any inductors too close to any transformers or you will get some hummmmmm. Better still - get some speakers with no crossover to start with :dance: . I never tried moving the padding resistor and 3.3uf cap on my nva style speakers back to the amp or even inside it. There are no inductors involved to pick up transformer emi so it could go right on the end of the amp board. :think:

That got me thinking about doing the high pass filter at line level in the power amp's input stage and ditching the 3.3uf cap. But i dont know what effect that would have and if it would play nicely with a passive resistive volume control. Also no cap before the tweeter equals good bye tweeter if the amp goes dc at any time.
DIY inspired by Richard "The Doc" Dunn RIP

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karatestu
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Re: DIY thoughts of the day

Unread post by karatestu » Thu Oct 10, 2019 8:04 pm

Listening to my system now waiting for my band members to show up for rehearsal. Got a pub gig on Saturday.

I wish it sounded this good through the day as well. It's magical now unlike earlier when it gave me a headache. Bloody farmers polluting the mains supply round here :roll:
DIY inspired by Richard "The Doc" Dunn RIP

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karatestu
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Re: DIY thoughts of the day

Unread post by karatestu » Tue Oct 29, 2019 5:25 pm

Copied this from another site

"This is the musicians dillemma and why they are typically not good evaluators of sound reproduction. They only hear the performance. If the performance is good then the reproduction is good and vice-versa. Until you can learn to seperate those two very distinct things - the performance and the reproduction - you will never understand what I am talking about. One can be good and the other bad, they are distinctly seperate things."

i am not sure what to make of this . I am leaning to the view that it is mostly :Bllocks:
DIY inspired by Richard "The Doc" Dunn RIP

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slinger
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Re: DIY thoughts of the day

Unread post by slinger » Tue Oct 29, 2019 6:15 pm

karatestu wrote:
Tue Oct 29, 2019 5:25 pm
Copied this from another site

"This is the musicians dillemma and why they are typically not good evaluators of sound reproduction. They only hear the performance. If the performance is good then the reproduction is good and vice-versa. Until you can learn to seperate those two very distinct things - the performance and the reproduction - you will never understand what I am talking about. One can be good and the other bad, they are distinctly seperate things."

i am not sure what to make of this . I am leaning to the view that it is mostly :Bllocks:
I'd go so far as to say self-important pseudo-psychological :hbs:
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

Daniel Quinn
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Re: DIY thoughts of the day

Unread post by Daniel Quinn » Tue Oct 29, 2019 6:24 pm

It isn't. It's fairly simple and starightforward language. It may be genius or shite, what it ain't is self important psudo psychological.

joe
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Re: DIY thoughts of the day

Unread post by joe » Tue Oct 29, 2019 6:42 pm

I'd have thought it was a statement of the bleedin obvious, meself.

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CN211276
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Re: DIY thoughts of the day

Unread post by CN211276 » Tue Oct 29, 2019 7:03 pm

joe wrote:
Tue Oct 29, 2019 6:42 pm
I'd have thought it was a statement of the bleedin obvious, meself.
and me.
I set a course just east of Lyra
And northwest of Pegasus
Flew into the light of Deneb
Sailed across the Milky Way

Sonore microRendu/MCRU PS, AQ J-bug, Wirewold Ultraviolet, Chord Mscaler-Qutest/MCRU PS, Geitnote Apogee, NVA BMU, P90SA, A80sMk2, Phono 1, SSP Mk 2, TSCS, TIS mk2, Cube 1s, Atacama stands, Rega Planar 3, Denon DL-110, Grado SR 325e, headphones.

Second system
Chord Mojo (also HP amp), NVA P20, A20, Cubettes, SSC, LS3.

Out and about
Oppo PM3, Audioquest Dragonfly Red.

R.I.P. Doc

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