Search found 462 matches

by Geoff.R.G
Tue Oct 08, 2019 7:21 pm
Forum: DIY
Topic: Measuring speakers for numpties
Replies: 24
Views: 662
Great Britain

Re: Measuring speakers for numpties

If you produce a frequency response curve for a speaker, having first built it to be subjectively satisfactory, you will have a reference against which you can evaluate other speakers. That assumes that the other speakers were measured in the same way using a similar microphone and measuring softwar...
by Geoff.R.G
Thu Sep 12, 2019 5:26 pm
Forum: DIY
Topic: Lead free so
Replies: 13
Views: 609
Great Britain

Re: Lead free so

+3 😀 No particular reason other than someone whose opinion I rated was very enthusiastic and after a bit of head scratching I think it might well have been the Mundorf stuff with the high silver content as I recall him saying it came from Germany. My digital soldering iron says it reaches 340c How ...
by Geoff.R.G
Sat Sep 07, 2019 11:38 am
Forum: DIY
Topic: Remote power supplies
Replies: 34
Views: 1725
Great Britain

Re: Remote power supplies

Yep, just be aware "noise" in this context is not always something you can hear from the speakers. Its why I measure things, but each to their own. I have no objections to measurement, or the use of a 'scope if that is what gets the job done. The 19KHz pilot tone can be seen on an instrument even i...
by Geoff.R.G
Sat Sep 07, 2019 11:29 am
Forum: DIY
Topic: Remote power supplies
Replies: 34
Views: 1725
Great Britain

Re: Remote power supplies

The more I think I know the more I realise how much I don't know. :) Don't feel too bad about that, I have spent the last 1/2 hour reviewing non-linear amplification, it is over 30 years since I did any in-depth radio study and much has changed in that time. Class D, and above, amplifiers for examp...
by Geoff.R.G
Sat Sep 07, 2019 10:47 am
Forum: DIY
Topic: Electrical Storms
Replies: 11
Views: 1046
Great Britain

Re: Electrical Storms

One prerequisite of these protective strategies is that one is actually in the house when a storm is expected or there is a power cut. That is a game I'm not playing, I can't be in all the time.
by Geoff.R.G
Fri Sep 06, 2019 8:44 pm
Forum: DIY
Topic: Input selector - switching the ground
Replies: 7
Views: 546
Great Britain

Re: Input selector - switching the ground

Hi Geoff. One of the mods we did on naim equipment yonks ago was to make the 0V connections as low impedance as possible. I did make a difference for the better. Pin 1 problem - i have read about that before but didn't take much notice :grin: Essentially the Pin 1 problem is that pin 1 can be signi...
by Geoff.R.G
Fri Sep 06, 2019 5:46 pm
Forum: DIY
Topic: Input selector - switching the ground
Replies: 7
Views: 546
Great Britain

Re: Input selector - switching the ground

May I recommend that you Google "The pin 1 problem". You will find a wealth of information, and unfortunately misinformation, on the subject. You may end up thoroughly confused but I can assure you that reducing the ground resistance does make a difference, even if my experience did involve audio so...
by Geoff.R.G
Wed Sep 04, 2019 8:10 am
Forum: DIY
Topic: Remote power supplies
Replies: 34
Views: 1725
Great Britain

Re: Remote power supplies

Because, just because you can't hear something, doesn't mean that its effect on the sound cant be heard. However it can be much harder to know what is causing the difference in sound. Simple and old example, the pilot tone from a FM decoder. Not audible, until you record the output on a tape record...
by Geoff.R.G
Mon Sep 02, 2019 5:00 pm
Forum: DIY
Topic: Remote power supplies
Replies: 34
Views: 1725
Great Britain

Re: Remote power supplies

Hi Geoff. Thanks for your observations. In your first post of this thread what did you mean by "capacitance of the feeder" ? Stu, If you take a piece of two core cable say 1m long it has resistance and capacitance. Any two conductors running parallel to each other for a, small, capacitor. So, if yo...
by Geoff.R.G
Sat Aug 31, 2019 10:34 am
Forum: DIY
Topic: Remote power supplies
Replies: 34
Views: 1725
Great Britain

Re: Remote power supplies

Stu, my observation, based on the Phono 2 design with separate PSUs for each stage of amplification, is simply that a bigger power supply will have more effect than will the cable (length wasn't what I meant). 30cm or 60cm of feeder from a PSU to an Amplifier won't make much difference in terms of r...