good progress, so pin 1 and 2 is your ac in, 12 and 13 the 5 volt filament winding.....
so that leaves pins 3 to 11..... 9 pins, 1 of which must be the center tap....what is the voltage between 7 + 11, same as 3 + 7? if yes, then you have a psu.....
you will need a filament traffo wit secondary rated for 4amps at least...yes you can use this traffo for a pp
so that leaves pins 3 to 11..... 9 pins, 1 of which must be the center tap....what is the voltage between 7 + 11, same as 3 + 7? if yes, then you have a psu.....
you will need a filament traffo wit secondary rated for 4amps at least...yes you can use this traffo for a pp
The voltage reading higher than spec is because of 1 higher line voltage 2 no load .. 7 is the center tap so it 3 7 11 give you a center tapped 400 volt unloaded close to 360 with a load depending on diodes used up tp say about 280 plus unloaded and about 250 with a load or use two of the tap and a full wave bridge for what ever voltage you want . Hope I am clear on this you will still need a heater supply this would make a great preamp transformer.
look here please and decide for yourself.....http://www.hammondmfg.com/pdf/5c007.pdf
transformer ratings can be exceeded a small bit depending on your ambient temperature.....
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Thank you Tony. the the full wave bridge choke input load would be the best choice with the least losses. Battradio has an interest in vintage equipment which may subconsciously skew his answers to a newbe? your post 21 pin 7+11 and 3+7 are the same voltages which you felt was a go for a pp 6bq5. I am getting conflicting answers. would anyone else have an opinion please! Can multiple taps be used to increase voltage and current? additional input is greatly appreciated
ask, ask and ask....links are are available to answer your questions.....
if you can post the dc resistance of pin 1 and 2 and that of pins 3 to 11 we can more or less estimate how much dc you are going to get....
between the Hammond engineers and the other poster, i'd choose Hammond' hands down...
are you using tube rects or ss? if i were you i'd go ss rectification so you can maximise your traffo...the power to be spent on heating the 5volt filament can instead be used for B+...
if you can post the dc resistance of pin 1 and 2 and that of pins 3 to 11 we can more or less estimate how much dc you are going to get....
between the Hammond engineers and the other poster, i'd choose Hammond' hands down...
are you using tube rects or ss? if i were you i'd go ss rectification so you can maximise your traffo...the power to be spent on heating the 5volt filament can instead be used for B+...
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It is easy: for maximum volts out use the 0V and the 125V and ignore the others. They are simply taps on the same secondary. If you need more volts use a voltage doubler. They are easy to build using diodes and caps. (google will help) But a doubler also cuts cuururent (product or volts and amps remains fixed)
The first thing to do with a "new to you" transformer is to measure the resistance between all the terminals.. You should be able to figure out how it is connected inside. Draw as best you can the internal connections.
Next step is to place about 1 to 12 volts AC on the primary and measure volts on the other windings. This will give the turns ratios. I use a 12VAC plug-in power cube for this kind of testing.
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If you calculate the power availible 180 volts at 150 MA it gives you 27 watts of B+ avalible . A tube is less than 50% efficient so that leaves 13.5 avaible for power out . Thats one 6BQ5 push pull amp .
EDCOR - XPWR139-120/240
This would be a good transformer for a stereo 6BQ5 amp it has 56 watts , which cut in half is 28 watts of B+ availible which is plenty for two channels of PP 6BQ5's
http://angela.com/hammondpowertransformer370hx.aspx This is used as a replacement transformer for a Dynaco st35
EDCOR - XPWR139-120/240
This would be a good transformer for a stereo 6BQ5 amp it has 56 watts , which cut in half is 28 watts of B+ availible which is plenty for two channels of PP 6BQ5's
http://angela.com/hammondpowertransformer370hx.aspx This is used as a replacement transformer for a Dynaco st35
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I'm building an EL84 based push-pull stereo amp. I looked at that Edcor transformer too. But I also looked at this Antek toroid transformer. If has twice the B+ current and sells at nearly 1/2 the price.
Antek - AS-2T230
Watch the voltage. The spec sheet says the max voltage on the plate is 300V The Edcor is a 280-0-280 volt transformers and will make more than 300V of DC.
Antek - AS-2T230
Watch the voltage. The spec sheet says the max voltage on the plate is 300V The Edcor is a 280-0-280 volt transformers and will make more than 300V of DC.
while i agree that a better transformer should be used instead.......i think that he can still get decent power out of this traffo, that is why i am asking for dc winding resistances..........that will tell how much this traffo can be maxed out..........
I have two Chicago PHC-165 waiting for the right project so i understand wanting to use a nice looking transformer . Also have two antek AN-1T350's waiting their turn , the problem with the toroids is by the time you buy or make an inclosure they are the same price as a conventional transformer .
http://www.bunkerofdoom.com/xfm/chicago1953/005.jpg
I have two UTC -CG-429's for my next project and two UTC- LS-58
for the output transformers .
http://www.bunkerofdoom.com/xfm/UTC_1956/UTC1956_25_0001.jpg
http://www.bunkerofdoom.com/xfm/UTC_1955_WEB/024.jpg
The transformer you have should be used with a pair of 845 as the bias transformer .
I would just hate to see such a nice transformer ruined by over taxing it .
It would be fine for a PP stereo 6AQ5's or single ended 6BQ5's .
Mark
http://www.bunkerofdoom.com/xfm/chicago1953/005.jpg
I have two UTC -CG-429's for my next project and two UTC- LS-58
for the output transformers .
http://www.bunkerofdoom.com/xfm/UTC_1956/UTC1956_25_0001.jpg
http://www.bunkerofdoom.com/xfm/UTC_1955_WEB/024.jpg
The transformer you have should be used with a pair of 845 as the bias transformer .
I would just hate to see such a nice transformer ruined by over taxing it .
It would be fine for a PP stereo 6AQ5's or single ended 6BQ5's .
Mark
122 Ohms times .15 squared is 2.7W. The primary current will be about 0.5A, another 1.2W. Core loss adds another watt or so, so there is about 5W, won't be TERRIBLY hot, but will go up fast (remember, current squared...) if current is increased beyond 150 mA. Choke input with full-wave bridge will give about 150 mA DC with 150 mA RMS in the secondary which might be barely enough...
If you buy the "AS" type from Antek they are overwound with a magnetic shield and don't need any kind of enclosure. Even the "AN" type is probably better then the typical IE type with end-bells.
I know that many DIY amp builders never bother to place their amps inside a cabinet but really it is not hard to do and then the argument about a finished appearance goes away.
I always put mine into something that is 100% "wife approved" for use in a living room. The last amp I built was a guitar amp and the visual style is not what I would like for a stereo but this gives the idea. I don't think it looks like something that is finished until you place it into a "period authentic" enclosure.
Here are some photos...
https://www.dropbox.com/sh/mhxjjw37gx2vl22/gaIfkyV9De
You can see in Photo #3 that the amp works just fine when laying bare on the floor. I was testing the finished amp and "high tech" speaker cabinet. It worked well but fail the WAF test badly.
The stereo amp I'm making now will go into a 17" wide wood cabinet with some TBD type exotic wood veneer face. The back needs to be open for cooling.
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like i said in my post#18, this traffo will find use in a nice preamp......
all indications are, this traffo is good up to about 50 watts max, looking at Tom Bavis's post....if not using the 5volt winding, heating will be lesser....
i will try this traffo in a pp amp.....
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