steve
Rank: Trio
Posts: 206 
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Post by steve on May 15, 2016 20:03:22 GMT
I like EL34s but I've never heard a particularly detailed output stage using them. Better than the harder 6550s though, I think. Unless you've heard EL34s configured as God intended, ie as true pentodes, then IME, you ain't heard them at their best. Admittedly, EL34s are not KT88s and their top end is not quite as extended as they are. So if you are after preternaturally insightful treble from your valves, then you need to look elsewhere. It is the midrange performance we are after with these particular pentodes and as far as I am concerned, nothing apart from 300Bs come anywhere near the EL34. They are magical valves when configured correctly; none of your ultralinear or triode nonsense  |
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Post by MartinT on May 15, 2016 20:48:23 GMT
If it's midrange liquidity you're after then I think the EL84 is king. Not a great deal of power, though.
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Post by Mr Whippy on May 15, 2016 21:55:09 GMT
Any dealings with the 813?
Being shallow, I just like the look of them.
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Post by Chris on May 16, 2016 5:03:26 GMT
EL34s are my valve of choice and certain 6CA7s can be even better.
Lovely build.
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Post by MartinT on May 16, 2016 7:16:04 GMT
Being shallow, I just like the luck of them. Lucky valves? |
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Post by MikeMusic on May 16, 2016 7:21:38 GMT
Steve
How much planning do you do before you start or do you instinctively know where everything is going ?
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Post by Mr Whippy on May 16, 2016 8:04:24 GMT
Being shallow, I just like the luck of them. Lucky valves? Just noticed it before I saw your comment. Don't know what I was thinking. No excuse. Must have been them two Linda McCartney Red Onion & Rosemary Sausage Plaits I had late on. Even forgot to log out. Sorry. |
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steve
Rank: Trio
Posts: 206
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Post by steve on May 16, 2016 8:35:44 GMT
Steve How much planning do you do before you start or do you instinctively know where everything is going ? There are a number of rules to follow when laying out a valve amp to avoid inducing hum into the circuit. Chokes for example need to be orientated at right angles to output transformers and similarly, mains transformers should be placed as far away as possible from the output transformer. With these rules in mind, layouts tend to form themselves. This is why valve amps tend to all follow the same conventions, eg transformers along the back and the input valves at the front. Once you know these rules, then it becomes second nature to lay out a chassis. There is room for creativity but engineering practice dictates where the components ought to go. Marking out however needs time taken over it, with "measure twice, cut once" and check before drilling, being the operative phrases. |
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Post by MartinT on May 16, 2016 8:48:26 GMT
Must have been them two Linda McCartney Red Onion & Rosemary Sausage Plaits I had late on. I think I was on the Ainsley Harriott Spicy Lentils that day. LOL - no worries! |
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Post by MikeMusic on May 16, 2016 16:17:58 GMT
Linda McCartney Red Onion & Rosemary Sausage Plaits I had late on. Like the sound of them Coming to a mouth near me very soon |
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Post by MikeMusic on May 16, 2016 16:18:56 GMT
Steve How much planning do you do before you start or do you instinctively know where everything is going ? There are a number of rules to follow when laying out a valve amp to avoid inducing hum into the circuit. Chokes for example need to be orientated at right angles to output transformers and similarly, mains transformers should be placed as far away as possible from the output transformer. With these rules in mind, layouts tend to form themselves. This is why valve amps tend to all follow the same conventions, eg transformers along the back and the input valves at the front. Once you know these rules, then it becomes second nature to lay out a chassis. There is room for creativity but engineering practice dictates where the components ought to go. Marking out however needs time taken over it, with "measure twice, cut once" and check before drilling, being the operative phrases. Thanks Steve Measure twice, cut once always for me ! |
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Post by Mr Whippy on May 16, 2016 20:51:46 GMT
I like EL34s but I've never heard a particularly detailed output stage using them. Better than the harder 6550s though, I think. Unless you've heard EL34s configured as God intended, ie as true pentodes, then IME, you ain't heard them at their best. Admittedly, EL34s are not KT88s and their top end is not quite as extended as they are. So if you are after preternaturally insightful treble from your valves, then you need to look elsewhere. It is the midrange performance we are after with these particular pentodes and as far as I am concerned, nothing apart from 300Bs come anywhere near the EL34. They are magical valves when configured correctly; none of your ultralinear or triode nonsense At dinnertime I was looking for mods to the Audioromy FU29. I have one and love it. Stopped using it however as I don't want to burn-out the mains transformer. Anyway, found this. Pure Pentode operation gets a mention, as does "DC Restoration": www.audioasylum.com/cgi/vt.mpl?f=tubes&m=237389&VT=T |
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Post by pre65 on May 17, 2016 8:12:13 GMT
Any dealings with the 813? Being shallow, I just like the look of them. 
The GM70 and GK-71 are similar in performance, but cheaper. |
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steve
Rank: Trio
Posts: 206
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Post by steve on May 18, 2016 16:07:25 GMT
Heater wiring is in on the first monoblock  |
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steve
Rank: Trio
Posts: 206
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Post by steve on May 18, 2016 16:08:48 GMT
And mono 1, as a result, lights up nicely   |
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steve
Rank: Trio
Posts: 206
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Post by steve on May 18, 2016 18:45:25 GMT
Now mono 2 has heaters.  |
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Post by MartinT on May 18, 2016 20:38:55 GMT
AC or DC for the heaters?
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steve
Rank: Trio
Posts: 206
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Post by steve on May 18, 2016 21:13:17 GMT
Heaters are all AC.
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steve
Rank: Trio
Posts: 206
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Post by steve on May 19, 2016 17:45:41 GMT
Mono 1 power supply is done. Rectifier is solid state, using 3A,1200V, Silicon Carbide Schottky Diode bridge.  |
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Post by MartinT on May 20, 2016 5:23:34 GMT
Proud to be Made in Britain!
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