Hi all,
Quite a few years ago there was a webpage by Paul Cambie and aslo Grant Wills which detailed the steps involved in determining if PA line transformers could be used as output transformers in valve amps.
The webpage by Paul Cambie went into great detail, As an untrained tech myself, Pauls webpage set out the details in tables that was very easy to understand.
Both of these webpages no longer exist, I know there's links on Oz Valve amps site with some information but it doesn't go into detail like the original page did.
I'm wondering if anyone has kept a copy his webpage that you could post a copy here, I thought I had printed it off at the time. I have two line output transformer that I'm trying to work out if I can use them.
I've found one video on youtube which isn't very helpful and there are a few threads here eluding to this information but nothing which details the steps as the original webpage by Paul Cambie had done.
cheers if anyone has this information. they could post.
Quite a few years ago there was a webpage by Paul Cambie and aslo Grant Wills which detailed the steps involved in determining if PA line transformers could be used as output transformers in valve amps.
The webpage by Paul Cambie went into great detail, As an untrained tech myself, Pauls webpage set out the details in tables that was very easy to understand.
Both of these webpages no longer exist, I know there's links on Oz Valve amps site with some information but it doesn't go into detail like the original page did.
I'm wondering if anyone has kept a copy his webpage that you could post a copy here, I thought I had printed it off at the time. I have two line output transformer that I'm trying to work out if I can use them.
I've found one video on youtube which isn't very helpful and there are a few threads here eluding to this information but nothing which details the steps as the original webpage by Paul Cambie had done.
cheers if anyone has this information. they could post.
Alas it doesn’t look like Archive.org crawled the site. It was a personal page on a larger host.
http://home.alphalink.com.au/~cambie/6AN8amp/M1115.htm l
Maybe someone else can try.
http://home.alphalink.com.au/~cambie/6AN8amp/M1115.htm l
Maybe someone else can try.
What a great article that is, Its similar to a SE 807 amp circuit that I found in the Sept 1949 issue of Australasian Radio World magazine I'd like to build.
again thanks heaps for this article.
A bit surprising how many hits there are on that article yet they are all links to the now gone original page rather than saves. Paul Cambie's article (titled "6AN8 & EL84/6BQ5 Project Amplifier") is referenced on the forum here though so I'd bet somebody in one of those threads has downloaded it. (Gnobuddy, BallPencil for two). Others have also refernced Cambie's article over on the AudioAsylum.
Also, don't forget there are plenty here who have played around with with alternatives to expensive output transformers. Member Shoog did a lot with toroids as I recall . . . . bet there's a fair bit. Found this thread in a quick search.
Yes, I've seen that info on OZ valve amps, However, for the untrained like me, unlike Oz valve amps The original document by Paul Cambie went into great detail which steps you through the process in great detail.
cheers anyway
I remember that article on the Altronics M1115 line transformer. The author describes an amplifier using a pair of EL36's in PP with the M1115 as OPT. He even found out that the 2.5W and 10W taps are suffciently close to the 5W center tap so that they can be used for UL purpose.
Best regards!
Best regards!
Spreadsheet attached for working out impedances and UL ratios (if available). Note that these PA transformers lack enough primary inductance to support higher powers at low frequencies (primary windings are all rated for 100V RMS @ 30 Hz). For instance the M1120 run as 8k A-A can only manage 20W above 120Hz (400V RMS A-A). Mains toroids are better in this regard.
Yes, for sufficient performance it is better to connect two of these transformers primaries in series and the secondaries in parallel, using Norman Crowhurst's cross coupled design.
In contrast to the Altronics line transfromers from OZ comparable European ones only allow for even lower primary voltages of just 282 Veff across the primary, see the Omnitronic datasheet for instance.
Best regards!
In contrast to the Altronics line transfromers from OZ comparable European ones only allow for even lower primary voltages of just 282 Veff across the primary, see the Omnitronic datasheet for instance.
Best regards!
I have the 3 saved, Cambie, Wills and ozvalveamps, and I have zipped them into the attached file.
Regards, Trevor
Regards, Trevor