Turtlerock Forum

Hey guys,

So I'm really new to this whole DIY thing. In the past I've only built a JLM mono and changed a few tubes in some gear.

I have no idea where might be the best place to pick up just two Lundahl 2912's. I sent CDA an email, the Lundahl distributor for our region and they never followed up with a quote. Is there anyone that stocks these? It seems a bit silly to have just two shipped from overseas on their own.

Cheers!

Peter Holz ('Peat' on this forum) bought some Lundahl transformers from control devices last year, I think. Maybe he can chime in?

Oh yeah! I forgot about that. I think he mentioned it in another thread, but it was one of those "openplanrecording" guy's threads, so it's been deleted. Thanks for reminding me.

I've bought from control devices before. It took ages with really poor communication from their side and was a little expensive. If I do it again I will be ordering from one of the us suppliers or direct from lundahl. That being said I'm pretty small fry for a national distributor as I was ordering just two tx.

M

Sure, Myles, you're small fry, but who are they selling to? How many Proharmonics or Pickstones are there in the country and how many would they purchase? And I'm not aware of any retail outlets.

David try contacting Pharujee Tangkunboriboon from CDA..... email- bo@cda-proaudio.com

He was very prompt at returning my email for 4 lundahl's a few months ago.

cheers

sorry Anthony try...........as above

Thanks Ben, anyway. I might be in the market for them sometimes!

Hi Guys, in defense of all suppliers and agents, remember when we go to order a small quantity of an esoteric item, e.g. a Lundahl or Sowter transformer, we are a very small market. It is un-economic to keep even a small quantity of stock unless they are a very commonly used line as the cost of keeping it sitting on the shelf waiting , just in case someone wants one or two someday, from a business perspective is very high.Also there may be a delay in getting them into the country. Sure you can buy a couple on ebay and get them in without attracting much attention, but if your business is importing gear/components you'll have to operate with customs clearance on everything you bring in, and that costs a lot. Hence why you may save orders and get a shipment every few months to spread the freight and customs cost. That said however, there is no excuse for poor communication.
Don't forget that there is a local manufacturer of very high quality audio transformers ... Harbuch and they do keep stock and can make to order within a week. Many Australian broadcast facilities have gear with Harbuch transformers, the ABC is full of them. Harbuch make a lot of transformers for medical and scientic applications so the quality is exceptional. http://www.harbuch.com.au/audio_9.html

Remember too that some things must be shipped by sea-freight , not Air freight. A good example here is certain types of loudspeakers for instance, where the extreme cold in an aircraft hold can cause a ceramic magnet to change it's flux level and alter the speakers performance. This occurred with some Tannoy speakers a few years back. Air shipped speakers lost sensitivity and the magnets were found to be reduced in flux level...and there's a whole new topic

Yeah Harbuch make excellent transformers and I've used them for a range of things. When I ordered them they were very helpful and very fast. We even talked about making something custom and they were very helpful with that too even though we didn't go down that path. And the price for the custom work was only a small amount more than their standard units.

Alastair Reynolds wrote:Remember too that some things must be shipped by sea-freight , not Air freight. A good example here is certain types of loudspeakers for instance, where the extreme cold in an aircraft hold can cause a ceramic magnet to change it's flux level and alter the speakers performance. This occurred with some Tannoy speakers a few years back. Air shipped speakers lost sensitivity and the magnets were found to be reduced in flux level...and there's a whole new topic

what is it with you and aeroplane trivia ?
now i have NEVER HEARD A THING ABOUT speakers and planes except Bruce Jacksons personally decking out elvis's jet plane so elvis could listen to the same monty python cassette over and over ...

tell us the tannoy aeroplane story its sounds curious

Alastair Reynolds wrote:A good example here is certain types of loudspeakers for instance, where the extreme cold in an aircraft hold can cause a ceramic magnet to change it's flux level and alter the speakers performance. This occurred with some Tannoy speakers a few years back. Air shipped speakers lost sensitivity and the magnets were found to be reduced in flux level...and there's a whole new topic

Tis an interesting concept. I'd imagine the magnet would become almost brittle at those temps. Shrinking and expanding all at the same time with the effects of altitude plus extreme cold.
Imagine how many speakers are in the air (at 35 000 feet) right now.

I'd like to hear more Alastair.....

Well it goes sort of like this......Material Science 101
ceramic magnets are brittle at the best of times, more so when they get very cold. Most magnets have a maximum operating temperature, up to which they will operate without any permanent degradation and then a curie point at which they totally lose all magnetism. Between these 2 temperatures varying degrees of degradation occur and are generally not recoverable. These temperatures vary depending on the composition of the alloy . An Alnico magnet will exhibit different characteristics to a ferroba or a ceramic composition, hence why we use different magnets for different applications or cost points (But don't Alnicos sound nice) Extreme cold will have a similar effect to heating beyond the maximum operating temperature so a degree of degradation of the flux density will occur and as such a reduction in the sensitivy of the loudspeaker for a given drive voltage.
a very basic experimental example of this can be found at http://www.creativekidsathome.com/science/magnetp3.html which shows differnce in magnetism relative to temperature.
heating does have an interesting effect on iron as when iron is heated above the curie point and the process of austenetization begins to occur, there is an increase in the amount of carbon that the iron can absorb and change from body centred cubic to face centred cubic structure .-- metalurgy rears its ugly head again. You can tell here I spent too much time around mines when I was a kid.... the joys of a long family history of metalurgy and learning how to tell an azurite from a chrysoprase when you're 5 years old.
The Tannoy story was recounted to me by Brian Murphy and Robert Findlay (Both RIP) of Syntec in the early 90s and concerned the air shipping of 3809 Dual Concentric "Gold" drivers (from memory). Some were rushed out by air and the rest came sea freight. The air shipped ones were noticibly inferior and when analysed it was found they had-- you guessed it-- a reduced flux level in the ceramic magnet. I imagine a similar thing could occur to an air shipped ribbon mic with a rare earth magnet, so carry them as hand luggage and keep them warm. treat them with love

Thanks for your help guys! And cool info Alastair, I never imagined cold could damage anything like that.