DIY thoughts of the day

A place for DIY project discussions.
Forum rules
1. No ad-hominem
2. No spamming or shilling
User avatar
karatestu
Posts: 1336
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu » Wed Aug 22, 2018 7:26 pm

Farnell, rapid or RS for components. That way you will avoid the resellers
Naim, Linn & Harbeth fanboy

OrangeFixie
Posts: 24
Joined: Sat Apr 29, 2017 6:25 pm
Location: Bristol, UK.
Great Britain

Re: DIY thoughts of the day

Unread post by OrangeFixie » Thu Aug 23, 2018 7:23 pm

That's useful info, thanks.

User avatar
karatestu
Posts: 1336
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu » Thu Aug 23, 2018 7:27 pm

No problem. Finding the parts on farnell can be a challenge unless you know exactly what you want. Use the refine search parameters to narrow the choices down as they have lots of every part you can think of.
Naim, Linn & Harbeth fanboy

User avatar
karatestu
Posts: 1336
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu » Wed Sep 05, 2018 2:07 pm

Bloody volume controls.

I have not had a volume control or source selector for quite a while now. Just play at one volume - I chose a resistor value (604R or thereabouts) which was neither too loud with loud recordings or too quiet with quiet recordings. Switch sources by turning off and swapping cables round. I could live with this arrangement but for family use I will have to include vol control and source selector.

Well, I chose the switches and resistors I was going to use a while back (hifi collective). I can work out the minimum and maximum resistor values I need for the volume needed. I can then build in a control for the maximum volume that will be achievable - no party style volumes which will cause clipping or overheating and burnt out drivers. I like the idea of having mono switches to act as a balance control (like P90?) but could the idea be taken even further?


I am ultimately going for 6 nva based monobloc amps, two for the isobaric bass 12 inchers, two for the 5" mids and two for the tweeters. I got to thinking that why couldn't I give each power amp its own volume control. That would be the ultimate in fine tuning levels between the drivers and channels, maybe I could even get rid of the padding resistors on the tweeters :dance:

Then I thought of the practicalities of it and turning 6 knobs just to turn the volume up and down :roll: . Then I had the brain wave of having two stepped attenuators with nobs (right & left channels) and then running the other four switches on sprockets and chains driven from the main ones. This makes it impossible to change volume between say mid and tweeter UNLESS the changes needed are built into the attenuator via differing resistor values. So the tweeter attenuators could have different values of resistor that account for the increased level brought about by removing the padding resistor.


It all turned out a bit complicated don't you think ?
Naim, Linn & Harbeth fanboy

User avatar
Dr Bunsen Honeydew
Posts: 29346
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Great Britain

Re: DIY thoughts of the day

Unread post by Dr Bunsen Honeydew » Wed Sep 05, 2018 2:39 pm

You are BONKERS!

User avatar
karatestu
Posts: 1336
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu » Wed Sep 05, 2018 3:18 pm

Its great being bonkers ya know :dance:

Where hifi meets agriculture
Naim, Linn & Harbeth fanboy

Chunk McDaniel
Posts: 281
Joined: Wed Mar 01, 2017 10:25 am
Great Britain

Re: DIY thoughts of the day

Unread post by Chunk McDaniel » Wed Sep 05, 2018 3:53 pm

:o :lol:

Lurcher300b
Posts: 637
Joined: Tue Jun 14, 2016 1:58 pm
Great Britain

Re: DIY thoughts of the day

Unread post by Lurcher300b » Wed Sep 05, 2018 4:02 pm

Then I had the brain wave of having two stepped attenuators with nobs (right & left channels) and then running the other four switches on sprockets and chains driven from the main ones
Or you just build the attenuators on switches with more gangs.

For example http://solidgreen.co.jp/products/pdf/SEIDEN.pdf

User avatar
karatestu
Posts: 1336
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: DIY thoughts of the day

Unread post by karatestu » Wed Sep 05, 2018 4:48 pm

Thanks for that Nick. I did not realise that you could get more than two gangs.

So I could have a 23 step with 4 gangs on each channel (left & right). I would wire bass, mid & tweeter amps to separate gangs and the fourth one would be unused.

This is only worth doing if I can play around with resistor values so that bass, mid and tweeter may have different attenuation according to the differing levels that are needed. So if I was to get rid of the padding resistor on the tweeters I could put a higher range of resistors in for that gang. With it being logarithmic that makes it harder but not impossible.

Then there is the possibility of my system moving rooms or component changes which means I have to redo all the resistor values again. Plus with good quality switches and resistors this is getting a bit expensive and very complicated.

More thinking to do. Not sure it is worth all the hassle.
Naim, Linn & Harbeth fanboy

User avatar
Dr Bunsen Honeydew
Posts: 29346
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Great Britain

Re: DIY thoughts of the day

Unread post by Dr Bunsen Honeydew » Wed Sep 05, 2018 5:24 pm

karatestu wrote:
Wed Sep 05, 2018 4:48 pm

More thinking to do. Not sure it is worth all the hassle.
That is why I don't do it.

Post Reply