HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

Alfi wrote: ↑Sun Feb 18, 2018 9:23 pm

karatestu wrote: ↑Sat Feb 17, 2018 8:30 pm My head is full of thoughts about phase although i dont thnk i fully understand the concept. Caps and inductors produce phase shift. Getting rid of them by doing the filtering mechanically at speaker level is one way of minimising phase shift. At line level removing coupling caps and output inductors is another means of attack.

I am unsure how caps and inductors to ground affect phase but they clearly have some bad effects as can be seen from the improvements made by removing the zobel network. My power amp has a low pass filter in the input section with a cap to 0V but i dont want to remove it as it keeps out rfi.

Dr Bunsen Honeydew wrote: ↑Sat Feb 17, 2018 8:31 pm Stop thinking and start listening.

Sage advice from the Doc there Stu - you know he knows best m8

Alfi.

PS the loaner BMU is doing good things here

Yes i know Glad the bmu is working for you. It does good things here too

Les W has been very poorly of late and has had some work done in hospital to sort out an artery in his heart which was 99% blocked

He now says he is feeling better than he has in years and a few projects will be finished off this year. Very good news for all Avondale users and fans of good sounding, well made, foo free and no slurp audio equipment

Hello Stu.

Really saddened to hear that Les has been in hospital but also really glad to read he's now feeling much better.. Please pass on my deepest regards to Les when you see him, he's a Top bloke.


Alfi.

Realised one of my power amps with filters removed has a higher heat sink temp than the other channel. Bias on both are the same. Only difference is the cooler one has 2.5 metres of LS6 and the hotter one has 5 metres of LS6. They are still running cool but one being warmer than the other i thought maybe the speaker cable being twice the length was the reason.

Swop the cables over to the other channel then you will know. It is highly unlikely to be the cable.

Come to think of it the warmer one is close to a radiator. Might be that

Link to les' newest boards. Not the ones i was talking about earlier but even newer ones. Complimentary output stage, current mirrors for the front end transistors, front end regs built in. Still has filters though

http://www.pinkfishmedia.net/forum/thre ... ect.212730

A bit more complicated than an NVA board

My next experiment is going to be this...............

Cable related. I have a pair of TIS mk2 cables between my cdp and my one step attenuator. There is only one 0V connection from cdp to pre as the Naim cdp motherboard has lots of separate ground planes which all join each other at the signal out end of the player.

So I only used the 0V connection on the right channel TIS cable. The 0V connection on the left channel TIS cable is left unconnected at both ends - ie the phono socket terminal is not soldered to anything at either end. So in effect I am only using one half of the left channel TIS cable I thought that if i used both 0V connections (left & right) that a ground loop would be produced and huuuuummmmmmmm. Especially as the left and right channel cables do not follow each other closely (on purpose).

Here comes the experiment (if you haven't turned off already) Cable capacitance is reduced when the feed and return are spaced apart. A TIS cable has both signal and 0V return within it, in shotgun mode with maybe a faraday cage between them (unsure about this). I have just purchased a 1M TIS mk1 digital cable (same as a single TIS cable) and it is sat here doing nothing at present. The plan is this

1)Use the mk1 TIS for 0V connection between cdp and passive pre. I would use both signal and 0V wires inside the TIS for 0V. Soldering in the cdp and passive would require the hot and cold terminals in the phono socket to be connected electrically. This would allow the cable to be used as it is.

2)Use each of the mk2 TIS cables for signal only, one for right and the other for left channel. I would then electrically connect the relevant hot and cold phono socket terminals in the cdp and pre. So in effect all the cores in each mk2 TIS would be used for the transmission of one channel of musical content.

In my mind this gets the signal and 0V away from each other completely and provides more cores for each task. Plus i can use the cables as they are (not that i would butcher a TIS cable anyway). I have no idea what the effect of this is going to be if any.

You are over complicating again, leave the cables to do what they are designed to do, and connect both earths you will get no hum loop. The only reason it is working now and not screaming at you is they are twinned elsewhere.

Right o . Another ridiculous idea put to bed