I've decided to build my self a spud headamp. I'm thinking on the lines of Squeezebox --> spud --> AKG701.
I've got a few 6EM7 that should do the trick. The only SE transformers I have are 5k->8R scavenged from a reel to reel tape machine, I think the original amp had EL84 as output tubes.
I'm quite new the tube side of life, so can any one tell me if a 5k - 8T SE transformer will work ok ?
6EM7 --> 5k..8R --> 65R (AKG701)
If not I have in mind a multitap transformer, made by Oxford Electrical Products, part number N35A002F, RS part number 210-6475 (rswww.com), not sure if this link will work http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2106475
The windings with ratios can be found here:
http://img-europe.electrocomponents.com/images/L217567-01.gif
If I can avoid spending more money that would be ideal, otherwise, I believe I can go for the OEP transformer.
Comments much appreciated
FS
I'm based in the UK, most US items end up costing lots of money with S&H charges applied
I've got a few 6EM7 that should do the trick. The only SE transformers I have are 5k->8R scavenged from a reel to reel tape machine, I think the original amp had EL84 as output tubes.
I'm quite new the tube side of life, so can any one tell me if a 5k - 8T SE transformer will work ok ?
6EM7 --> 5k..8R --> 65R (AKG701)
If not I have in mind a multitap transformer, made by Oxford Electrical Products, part number N35A002F, RS part number 210-6475 (rswww.com), not sure if this link will work http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2106475
The windings with ratios can be found here:
http://img-europe.electrocomponents.com/images/L217567-01.gif
If I can avoid spending more money that would be ideal, otherwise, I believe I can go for the OEP transformer.
Comments much appreciated
FS
I'm based in the UK, most US items end up costing lots of money with S&H charges applied
With triodes, maximum output is achieved with a load impedance of 2-3 times the tube's plate resistance. Higher impedance will reduce output somewhat, with lower distortion - a good trade-off with headphones.
5K will work fine, and you can even deliver close to a watt to an 8 Ohm speaker if you want. Depending on the sensitivity of the headphones, you may want to attenuate the output with a series resistor or voltage divider. You should terminate the 8 Ohm output with 8-10 Ohms.
5K will work fine, and you can even deliver close to a watt to an 8 Ohm speaker if you want. Depending on the sensitivity of the headphones, you may want to attenuate the output with a series resistor or voltage divider. You should terminate the 8 Ohm output with 8-10 Ohms.
excellent !
I've got all the ironware, I've just need to sort the caps and Rs and I'm ready to go.
I'll report on my progress as appropriate.
Thanks for your help Tom
I've got all the ironware, I've just need to sort the caps and Rs and I'm ready to go.
I'll report on my progress as appropriate.
Thanks for your help Tom
You may be fine just using the phones as the load. Try it, and if you lack bass, put a resistor in parallel to the load to see if that helps. Start with about 30R, and move lower if you think it helps.
no. This is the same advice Tom gave, I just said to start with 30R while he said to start with 8 to 10R.
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