120W PP EL34 amplifier re-born. – Page 3 – UK Vintage Radio Repair and Restoration Discussion Forum hypoxic brain damage recovery

There are loads nanoxia deep silence 120mm ultra quiet pc fan of mistakes on mine andy, I cocked up on a regular basis and made loads of blunders and those joints took weeks, just keep at it and it’ll be reet. My workbench is an old window sill, one end screwed onto the extension window sill outside, tother end on a table sitting on a baulk of wood, with an old vice screwed on, tools = chainsaw, an old stanley plane that cuts wonky, wilko tenon saw and some old chisel’s and a few clamps. I did most of the planing kneeling on a cushion with the wood against the door jam, so it’s possible to do reasonable work with not much. Before I made this, my woodwork was more a la’ homer simpson than leanardo di vinci. I think the secret is keeping your tools sharp and checking everything with a good straight edge.

To be honest after listening to them for a bit, I’m a bit underwhelmed. Bass is good and without using too many superlative’s is rich and natural sounding, IE a double bass sounds more like a double bass anxiety disorder definition than on my tranny amp, but apart from that I don’t know that a valve amp is any better than a tranny amp. Obviously I know there’s a lot of BS and hype about hifi, but still… I won’t be using them anxiety test as my everyday amp, my lekky bill has doubled this year, it’s likely if I used them all the time I’d be chucking more £’s to the lekky co.

I’m using a mitsubishi silicon power amp that was GIVEN to me by the next door neighbour, they were going to chuck it on the recycling! It cleaned up lovely and it sounds pretty darn good to my tired old ears. I have no ideological bias towards vacuum toobs or silicon apart from I find a certain "romance&quot hypoxic ischemic encephalopathy prognosis; in an old school valve amp which for me is as good a reason as any.

You say you can’t hear a difference between a £5 turntable and a £500 one? Dare I say it thats because your £5 used deck would likely have cost the equivalent of £500 in its day and is therefore no mean machine. Also a lot of people don’t take the time to set their turnatbles up in respect of a decent vibration free support, levelling and fetting arm and cartridge alignment. You can get really good results from very modest gear if a bit of time is invested getting it working right.

Not surprised your cambrideg CD sounds better than a PC drive, it only has one job to do, probably has a decent linear power supply or if SMPS it’ll have been designed to have low noise etc. I know I’ll get pilloried from some sections but I do think the current crop of good well designed and hypoxic brain injury post cardiac arrest made CD players squeeze a lot more off the much maligned CD than was previously thought possible. I have tried hi res downloads and I do not feel i am missing out on anything when I listen to old fashioned (!!!) CD. Anyway thats off topic, hope you sort yer anoxie définition hums out, nothing more frustrating.

Well spotted T, what a clanger! Some good point’s there also about the design, I can only say that any design faults are due to it being the first amp I designed, I was feeling my way, trying out this or that circuit till I arrived at one that worked. It’s too late now to change anything, the thought of having to start again is unthinkable.

My problem at the time of design was causes of hypoxia at birth getting full whack out of the OP stage. I remember being able to get about 90w out it (before application of NFB), but nothing more. I was advised to stick at this, but decided to ignor that advise as it would have been a waste of 6 OP valves etc. Two things got me over that hurdle, 1) using the 12BH7 as cathode follower’s and 2) reducing the OP stage grid R’s to 47k from 100/200k ish.

As I said I was a complete novice when I started hypoxic ischemic encephalopathy prognosis adults both in terms of electronics and valves. I mostly used the valve wizard site for how to draw loadline’s etc, but there are very few sources of "how to build a multi/parallel valve OP stage", I used three main sources of info. 1) GEC an approach to audio frequency amplifier design – especially the 400w amp. 2) this amp – http://www.Turneraudio.Com.Au/100w-monobloc3-2014.Html and other info on his site. 3) this amp – http://www.Chambonino.Com/construct/constwire2.Html

"You say you can’t hear a difference anoxia cerebral sintomas between a £5 turntable and a £500 one?" no, maybe my hearing is a bit knackered, I havn’t looked after it, using power tools with protection, standing in front of PA stack’s at motorhead gigs etc, however I went to wigwam hifi show where there were numerous setup’s of "top end" hifi, I left unimpressed having heard nothing that bought on an epiphany.

I’d use a bit of twin core screened microphone cable, connect one inner conductor to the screen at the socket outer (earthy end) and then connect the 2 inner wires up at the valve grid and ground respectively if that makes sense to you? If you havent got twin core, just use the screen as your earth return from socket to input valve, it might be enough. And make sure anxiety disorder meaning in bengali there are no other earth runs between input socket and inputs. Use insulated phono sockets as if its got electrical continuity with the chassis you are asking for trouble using the chassis as an earth return.

I generally don’t use a DC blocking capacitor on the input grids as it’s not really necessary unless you know that your source has a DC offset on it. All my preamps have output coupling caps or are designed for zero DC offset so I dispense with the DC blocking cap. None of my commercial valve amps use an input cap either. It doesnt do any harm though other than altering the LF response. I’m wondering if you’re picking up noise via the capacitor too.

You anxiety attack symptoms nhs’re using a toroidal mains transformer if I remember? You have a naturally low magnetic field surrounding it. Given a reasonable physical separation from the mains transformer(s) then the main source of hummy stuff is likely to be the AC heater wiring, power valves consuming between 1.5 to over 2A each can cause issues from the heater wiring. You already know about tightly twisted wires going to the bases and not having the wires causing a loop around the valve anxiety meaning in hindi symptoms base where the wiring continues to the next valve. And good earth referencing, possibly using a humbucker pot rather than the 2 x 47 ohm resistor pseudo centre tap trick.

Now I got to thinking here, are you still using the EL34 heaters in series with 18.9V feed per 3 valves? The issue here is that although the current through the chain anxiety attack meaning in hindi is kept at 1.5A, because the first valve in the chain has the full 18.9V across it, is there an increase in the hum field? Or is it purely current related, in which case its a clever idea. Again heres a daft maybe idea.If you are only drawing 1.5A per wiring run at 18.9V then an LM338 regulator will comfortably handle that current and regulated DC on the heater wiring will virtually eliminate hum. It can be argued that it doesnt matter on a push pull output anoxic event at birth stage due to self cancellation, but if the heater wiring gets close to other components then I guess there could be some small hum pickup off the heaters? I may have misunderstood here andy and you already are running DC heaters to your EL34 valves?