Advice on fixing a Thermionic Culture Vulture

[andre99]

Hi, I just picked up a second hand thermionic culture vulture only to find the left channel is very noisy. Hard to describe the noise - much more than a hiss but not crackly - certainly unusable. The channel is still working in terms of producing overdrive/distortion and the levels are fine, it's just really noisy. Seems to be worst when the bias gets turned down.

Could anyone recommend a tech that might be able to fix this, preferably in Melbourne?
Does anyone have any ideas as to what's going on and if it's fixable?

Thanks again

[audioio]

Audio Chocolate is the distributor and its retail arm is Awave in South Yarra.

[gigpiglet]

if its out of warranty and needs repair
as far as im concerned best tech in the country is rob squire at proharmonic
on the board here, and easy to find his details
you would have to post to adelaide - but well worth it.
great work, fair rates, top bloke.

[The Tasmanian]

Agree 100% with Gareth.
Rob is THE TechGod

[waitup]

I would replace the tubes first.

[Linear]

can you put your name in your signature? forum rules.

if i were you i'd swap L/R tubes. if the problem swaps sides, then it's tubes. if it doesn't, then it's time for a trip to adelaide.

Chris

[rob]

Yeah. What Chris says.

I'm also the authorised repairer for all products through Audio Chocolate.

[Linear]

well. I'm thinking of getting a run of 'WHAT WOULD ROB DO?' t-shirts made.

it's already helped me out a few times today...

Chris

[rob]

fine, just don't ask me that question ...

[andre99]

Thanks for your help everyone. I swapped the tubes and the noise swapped channels. Big relief, hopefully just a tube change.
I did some research and being a limited run (99 units) 11th anniversary model they've used Mullard M8196 and M8100 tubes. Apparently they are super high quality military grade (hence the M) tubes. Have contacted Thermionic to see if they can point me in the right direction. My local shopping centre doesn't stock Mullard military grade M tubes.

[rob]

beware the wankery with fancy tubes
you can contact Evatco in Australia with what you are after and in your case probably ask for the more readily available equivalents to those tubes and for a small fee they will match and noise test selected tubes for you.

[zenelectro]

Thanks for your help everyone. I swapped the tubes and the noise swapped channels. Big relief, hopefully just a tube change.
I did some research and being a limited run (99 units) 11th anniversary model they've used Mullard M8196 and M8100 tubes. Apparently they are super high quality military grade (hence the M) tubes. Have contacted Thermionic to see if they can point me in the right direction. My local shopping centre doesn't stock Mullard military grade M tubes.

The M8100 is a miniature Pentode, easily found and pretty cheap. Equivalents are 6AK5W, (used in quite a few
tubes mics) and 5654. Western Electric also made an equivalent called a WE403A which are very good tubes both
reliability and sound wise. They are also easily found and cheap.

The M8196 is also a miniature Pentode but with different grid connections (supressor is available for use).
Equivalents are 6AS6W, CV4011 and 5725. There are plenty of the latter available and they are also cheap.

You are just lucky almost no hi fi gear uses these tubes - then they would be 10 x the price!

[andre99]

Thanks Terry, Thermionic recommended the Jan5725 & 5654 as replacements (and for any Culture Vulture) but it seems there's quite a few substitutes.