Amp hum

[shuggz]

Chaps need some advice.

My amp is displaying a hum on one channel, disappears when the volume is at zero.

I've removed all the interconnects and the amp is wired directly to a dedicated spur, the amp is basically two mono-blocs and pre-amp on a single chassis.

I've just had it repaired/serviced/upgraded all the tubes were replaced, so am I right in suspecting it's a faulty pre-amp tube?

[hifi_dave]

If all sources are disconnected from the pre and the hum changes channel when you swop the incons to the power-amp, then it seems like a pre-amp fault. It could be a tube or it could be a component.

What are the pre and power-amps ?

[Ali Tait]

First thing I'd try is wiggling all the valves in their sockets,or removing and replacing them a few times to make sure the connections are ok.

[goraman]

The hum is in one channel, first swap output tubes left and right to see if the hum migrates with the tubes,it your preamp tubes are matched channels do the same.

if that dosen't help,take a pair of RCA plugs and each plug twist the input and return wire togather to make a closed loop.plug in your amp and disconect all the inputs then useing only your left and right twisted inputs switched to that source turn up the volume.If you still have a hum it could be a transformer,capacitor or unsheilded wire to close to a transformer,at that point take it to a pro.

[shuggz]

If all sources are disconnected from the pre and the hum changes channel when you swop the incons to the power-amp, then it seems like a pre-amp fault. It could be a tube or it could be a component.

What are the pre and power-amps ?

The amp is a Tube Technology Synergy 12 EL34's, 2x ECC 82 (LINE STAGE) and 4 x ECC 81 (DRIVER STAGE).
I've just had it repaired/serviced and upgraded, all the tubes were tested (apparently) TT mentioned there was a hum and traced it back to a faulty IC for volume control, they replaced it.

I'm a bit concerned as it was the right channel that was the original issue, this is where the problem is again, so I'll do the checks and report back.

[hifi_dave]

When you say 'TT', may I ask, who exactly did the repair ?

[Marco]

Tube Technology, I presume ;)

Marco.

[anthonyTD]

hi shugz,
as far as i know, the guy that originaly designed these amps still has no interest in doing anything with them due mainly to a tragic personal loss.
i have repaired these amps in the past and can tell you that the hum you are experiencing can be very difficult to trace due partly to the complexity of the bias system.
hope this helps.
A...

[hifi_dave]

Tube Technology, I presume ;)

Marco.

Well, I asked that question because Tube Technology was a one man band and that was Zia. Zia did a disappearing trick around 3 years ago leaving a trail of havoc behind him and I would really like to speak with him. If he is back and doing repairs, I would like to know.

[shuggz]

Anthony

You're quite correct in saying it could be the bias system but after having the amp repaired (at considerable cost) by Zia I assume that this issue would have been resolved, I'm not sure if the volume IC that had to be replaced is part of the bias system.
I have spoken to him and he has said to carry on using the amp, if it gets worse then he will resolve the issue if it's not a valve.
Unfortunately I don't know of anyone around here who could test the valves, so I'll have to suck it and see what develops.

HiFi Dave

Yes Zia is back in business and you can contact him via the TT site, the disappearing trick you refer to was prompted by the death of his wife, however death affects people in different ways, especially when your partner was also integral to the business.

I know enough so called premier manufacturers of AV/HiFi who offer products at premium prices, do not honour their warranties and royally shaft buyers when their kit goes wrong within the warranty period, those shits at Sony spring to mind.

So I won't slate the chap especially as he has been a perfect gent re my dealings with him and he is actively trying to resolve the so called havoc you refer to.

I accept that Zia's wife's unfortunate demise will have inconvenienced some owners, but there were enough talented people such as Anthony or Tim di Paravicini who could/did service TT kit.

Unfortunately the synergy I inherited was serviced by some spanner monkey who thought it might be an idea to disconnect certain components to make it operational, so I wound up with an amp running in ultra linear on one channel and pentode on the other :doh:

Anyway give him a call.

[hifi_dave]

Anthony

You're quite correct in saying it could be the bias system but after having the amp repaired (at considerable cost) by Zia I assume that this issue would have been resolved, I'm not sure if the volume IC that had to be replaced is part of the bias system.
I have spoken to him and he has said to carry on using the amp, if it gets worse then he will resolve the issue if it's not a valve.
Unfortunately I don't know of anyone around here who could test the valves, so I'll have to suck it and see what develops.

HiFi Dave

Yes Zia is back in business and you can contact him via the TT site, the disappearing trick you refer to was prompted by the death of his wife, however death affects people in different ways, especially when your partner was also integral to the business.

I know enough so called premier manufacturers of AV/HiFi who offer products at premium prices, do not honour their warranties and royally shaft buyers when their kit goes wrong within the warranty period, those shits at Sony spring to mind.

So I won't slate the chap especially as he has been a perfect gent re my dealings with him and he is actively trying to resolve the so called havoc you refer to.

I accept that Zia's wife's unfortunate demise will have inconvenienced some owners, but there were enough talented people such as Anthony or Tim di Paravicini who could/did service TT kit.

Unfortunately the synergy I inherited was serviced by some spanner monkey who thought it might be an idea to disconnect certain components to make it operational, so I wound up with an amp running in ultra linear on one channel and pentode on the other :doh:

Anyway give him a call.

Thank you for the information.

I do know the circumstances having been a friend of Zia for almost 30 years and I do sympathise but he has not been fair to his dealers, his customers and his friends. I won't go into this anymore and will (once again) attempt to make contact with him and if you do speak to him, please ask him to phone or e-mail me.

Many thanks,
David

[shuggz]

Thank you for the information.

I do know the circumstances having been a friend of Zia for almost 30 years and I do sympathise but he has not been fair to his dealers, his customers and his friends. I won't go into this anymore and will (once again) attempt to make contact with him and if you do speak to him, please ask him to phone or e-mail me.

Many thanks,
David


Spoken to Zia, he informs me that he's already spoken to you, so hopefully you've informed him of your views :)

[hifi_dave]

Yep, thank you and it's all sorted out to my satisfaction.

I am now looking forward to new Tube Technology products and will report here first.

[Marco]

Hi Dale,

Welcome to AOS! I've upgraded your account to trade status. Please feel free to use our trade section to advertise your company and its products, and also participate in discussions throughout the main forum :)

Enjoy!

Marco.

P.S Are you yourself from Brighton?

[Marco]

Hi Dale,

Thanks, and you're welcome. I live in Wrexham, North Wales, but the forum is not really 'based' in any specific location. We have a UK server, though.

I look forward to reading some of your contributions :)

Marco.