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Advice on fixing a Thermionic Culture Vulture

Posted:
Fri Feb 20, 2015 6:43 am
by 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
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Fri Feb 20, 2015 6:05 pm
by audioio
Audio Chocolate is the distributor and its retail arm is Awave in South Yarra.
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Sat Feb 21, 2015 4:01 am
by 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.
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Sat Feb 21, 2015 8:23 am
by The Tasmanian
Agree 100% with Gareth.
Rob is THE TechGod
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Sat Feb 21, 2015 10:02 am
by waitup
I would replace the tubes first.
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Sat Feb 21, 2015 6:28 pm
by 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
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Mon Feb 23, 2015 10:07 pm
by rob
Yeah. What Chris says.
I'm also the authorised repairer for all products through Audio Chocolate.
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Mon Feb 23, 2015 10:37 pm
by 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
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Tue Feb 24, 2015 8:55 am
by rob
fine, just don't ask me that question ...
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Wed Feb 25, 2015 10:47 pm
by 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.
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Thu Feb 26, 2015 9:17 am
by 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.
Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Thu Feb 26, 2015 5:06 pm
by zenelectro
andre99 wrote: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!

Re: Advice on fixing a Thermionic Culture Vulture

Posted:
Fri Feb 27, 2015 9:02 am
by andre99
Thanks Terry, Thermionic recommended the Jan5725 & 5654 as replacements (and for any Culture Vulture) but it seems there's quite a few substitutes.