On the Hiss

[Pigmy Pony]

Just noticed recently a bit of a hissing sound coming from the left speaker (there's always been a slight his from both, but you have to put your ear right up to the speakers to hear it). It doesn't intrude on the music, but when nothing's playing I can just about hear it from my seat. It doesn't get louder if you turn up the volume. Amp is an Audion Silver night 300b, with a Myryad Z40 pre going into it. Any thoughts? Is something likely to go BANG soon?

[Audio Al]

Move your seat back until you can't here the hiss :D

[Pigmy Pony]

Thanks for that Allen, helpful as ever :) I did try this, but then I found the humming from the fridge a bit obtrusive. Also a buzzing noise coming from the bedroom, which I'd rather not talk about.

So I thought I'd have a go at the valves. Brace yourself Allen, this is where it starts to get technical. First I switched the big valves round: no change. Then I switched the two little valves: result! Everything quiet again. The little valves have never been off since I bought the amp 7 years ago, so I wonder if the pins might get a bit cruddy over time?

[Audio Al]

Result , you could spray the pins with some deoxit D5 , on the tin it says

Dissolves corrosion
Improves contact
Protects surfaces

Give the wee little pins a birthay wash and brush up , Happy 7th :)

[struth]

or go solid state:sofa:

[Frazeur1]

Yeah but it gets so damn tiring removing all of those output transistors and cleaning their legs...Guess what else is there to do whilst on lockdown?:)

[AJSki2fly]

Just noticed recently a bit of a hissing sound coming from the left speaker (there's always been a slight his from both, but you have to put your ear right up to the speakers to hear it). It doesn't intrude on the music, but when nothing's playing I can just about hear it from my seat. It doesn't get louder if you turn up the volume. Amp is an Audion Silver night 300b, with a Myryad Z40 pre going into it. Any thoughts? Is something likely to go BANG soon?

I have a hiss/slight hum on my 300B set and different variations of it depending on whether I am using a MM or MC cartridge, which means I either have my SUT plugged in for MC or not. This issue I have found is primarily that certain RCA interconnects are really not great due to poor shielding, even though they may be expensive if they are used on the MC SUT side with a very low voltage then they pick up all sorts of crap mainly from transformers. A pair of Chord Chameleon V3's (£150 and many review recommended, I spit on them) are a waste of space unless used on on 0.5v signal or more, and even then I am suspicious of them. also the routing of the my phono cable is critical, even though it is a Furutech AG12.

I spent quite some time finding which RCAs worked best and the optimum position to place the SUT and phono stage in relation to each other and the main power amp, also where best to route the interconnects to avoid extraneous pickup. It still is not perfect and really i should re-site a 5 way power bloc completely away from the gear, which I may do over the next week or two. For a low voltage signal I have found that Belden 8402 microphone cable is very good, it has a low capacitance, and good shielding. see https://www.ebay.co.uk/itm/122439809318 or by some cable and RCAs and make your own up, https://www.designacable.com/belden-8402-microphone-cable-high-conductivity-copper-conductors-hifi-av-rca.html, I will be making some more up.

By the way Steve, if you don't plug your amp/pre and phono stage directly into wall sockets, I would recommend you do so, you will then get the cleanest AC supply possible with a normal set up I find separating them from all the other gear really make for a cleaner result, obviously if you have a mains conditioner than there should be no need.

[Pigmy Pony]

Thanks for that info Adrian, I only have one double socket anywhere near the gear, and quite a few things plugged in. However I've managed to give the 300b power amp it's very own socket, so that can only help :) No hum problems as far as I can tell with my set up, and the hissing sound I described earlier was purely from the amp, hissing even when everything else was switched off.

I will also get some of this Deoxit stuff Allen suggested, and give all the contacts a treat.

My stereo will be thinking it's Christmas, what with Deoxit, stylus cleaning gunk and magic sponge, and also the VTA gauge which arrived the other day. I just need to pluck up the courage to use it before:christmas:comes

[Pigmy Pony]

I have a hiss/slight hum on my 300B set and different variations of it depending on whether I am using a MM or MC cartridge, which means I either have my SUT plugged in for MC or not. This issue I have found is primarily that certain RCA interconnects are really not great due to poor shielding, even though they may be expensive if they are used on the MC SUT side with a very low voltage then they pick up all sorts of crap mainly from transformers. A pair of Chord Chameleon V3's (£150 and many review recommended, I spit on them) are a waste of space unless used on on 0.5v signal or more, and even then I am suspicious of them. also the routing of the my phono cable is critical, even though it is a Furutech AG12.

I spent quite some time finding which RCAs worked best and the optimum position to place the SUT and phono stage in relation to each other and the main power amp, also where best to route the interconnects to avoid extraneous pickup. It still is not perfect and really i should re-site a 5 way power bloc completely away from the gear, which I may do over the next week or two. For a low voltage signal I have found that Belden 8402 microphone cable is very good, it has a low capacitance, and good shielding. see https://www.ebay.co.uk/itm/122439809318 or by some cable and RCAs and make your own up, https://www.designacable.com/belden-8402-microphone-cable-high-conductivity-copper-conductors-hifi-av-rca.html, I will be making some more up.

By the way Steve, if you don't plug your amp/pre and phono stage directly into wall sockets, I would recommend you do so, you will then get the cleanest AC supply possible with a normal set up I find separating them from all the other gear really make for a cleaner result, obviously if you have a mains conditioner than there should be no need.

Has your slight hum only started since you re-organised your equipment? While your new layout looks great, could changing the proximity of certain components be responsible? Sorry if I'm stating the obvious :)

[AJSki2fly]

Well yes and no, when I was using the tv stand then I had issues with the phon stage being too close to a amp. Now I don’t it’s the routing of the cables and too many 12 and 15 volt transformers near the gear, so I need to tidy up a bit and move some stuff


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[AJSki2fly]

I have a hiss/slight hum on my 300B set and different variations of it depending on whether I am using a MM or MC cartridge, which means I either have my SUT plugged in for MC or not. This issue I have found is primarily that certain RCA interconnects are really not great due to poor shielding, even though they may be expensive if they are used on the MC SUT side with a very low voltage then they pick up all sorts of crap mainly from transformers. A pair of Chord Chameleon V3's (£150 and many review recommended, I spit on them) are a waste of space unless used on on 0.5v signal or more, and even then I am suspicious of them. also the routing of the my phono cable is critical, even though it is a Furutech AG12.



So a quick update on my Hum problem, I have now a much quieter system. I was partially right about the cause of the Hum, I decided to move my rack slightly and during this process I lowered the amp down a shelf and moved the LFD MMC phono stage uo immediately under the TT. Hum was now none existent when using the Goldring 2500 MI cartridge, so the issue was partially the phono lead previously running behind the amps transformers and picking up hum. However as soon as I re-introduced the MCX SUT back came the hum, not as bad as before but it was present. So I have today tried positioning the SUT in several places and have determined that any box with a transformer such as the TT power supply induces some level of Hum into it. SO I have for now found an optimum position for the SUT which reduces it to a very low level. But I think the next step will be to try and isolate the SUT from all things transformer as much as possible.:scratch:

[bosa]

I had a hum problem with my valve amp when using a TVC preamp.

Routing of cables helped and keeping the TVC as far away also helped. Two improvements I made were turning the amp about 45 degrees so the magnetic fields were presumably not aligned and an iron griddle on a shelf under the TVC! A bit extreme but it all helped to reduce the hum to an acceptable level.

[AJSki2fly]

So a quick update on my Hum problem, I have now a much quieter system. I was partially right about the cause of the Hum, I decided to move my rack slightly and during this process I lowered the amp down a shelf and moved the LFD MMC phono stage uo immediately under the TT. Hum was now none existent when using the Goldring 2500 MI cartridge, so the issue was partially the phono lead previously running behind the amps transformers and picking up hum. However as soon as I re-introduced the MCX SUT back came the hum, not as bad as before but it was present. So I have today tried positioning the SUT in several places and have determined that any box with a transformer such as the TT power supply induces some level of Hum into it. SO I have for now found an optimum position for the SUT which reduces it to a very low level. But I think the next step will be to try and isolate the SUT from all things transformer as much as possible.:scratch:

So a follow up, I moved the amp down to lower shelf, moved the tuner, CDP(Panasonic Blu-ray as transport), Beresford DAC & RPI/HiBerry to 2nd shelf with Rothwell MCX SUT tucked behind, LFD Phono-amp, Pro-Ject PSU, Schitt head amp and switch to 3rd shelf.

Result is its all easier to use and virtually no hum on vinyl side. :)

https://i.postimg.cc/W1RKWc05/35-B511-E0-D596-4127-B3-DD-052-F8-D8-CE901-1-201-a.jpg (https://postimg.cc/8jHtc3Kv)