PP3521 idht

[Paul Barker]

So rather disapointed with 1 watt per 6em7 due to lack of speaker efficiency at home. So went and looked at extremes of triode connected Beam tubes, I have some GE 6550’s probably nos but not boxed. So I looked at operating point.

So 5 watts per valve with 4% distortion looks listenable and five times the power of a 6em7.

I think I’ll try that.

[Paul Barker]

OK Ive found the trode characteristics rP 1k3 mu 8 S 6 ms/V so put those numbers in cathode capacitor with a load of 3k and cathode resistor 450 ohm we get -3db 7.6hz with 90uF bypass cap.

[Paul Barker]

But this wont be direct coupled monkey circuit because of voltage requirement. It’ll be RCL with grid choke. Same ECC88 volte amp driver plate load resistor 10k.B+ 400v cathode resistor of 6550 450 should pull it down from the above 11 watt circuit safely but almost as powerful. But its a choice of a autobias that wont need fettling. Err on side of safely under runnaway. The black gates after the choke input will be glad of a margin of safety now they are 25 years old. Not required to be series connected so 400uF capacitance. I’ll find the variac setting for b+ 400v and mechanically restrict turn of dial to that limit.

Now a I think Im in the right zone for what I have. I have one pair of Tungsol NOS 6550’s which I prefered the triode se sound from over kt88 gec and 6550 gec. I wont be short of SE power at home. Most listening will be around 3-4% 2nd. Extreme 7%. So should be ok. And the circuit will be safer with no byfilar wound components and no direct couple level to keep checking. Simple and reliable. If I dont find the Tungsols imdiately I have loads of other makes to start me off. It may not be worth the bother of building the gm70 amp. Well, no hurry.

[izzy wizzy]

The GM70 will only be worth building if you want that sound. I think the DH transmitter valves have that certain something but oh my, does it come with effort (weight, complexity, hard work, cost) Horses for courses as usual. Once heard, I was addicted. Bit like crack YMMV and all that.

[Paul Barker]

The GM70 will only be worth building if you want that sound. I think the DH transmitter valves have that certain something but oh my, does it come with effort (weight, complexity, hard work, cost) Horses for courses as usual. Once heard, I was addicted. Bit like crack YMMV and all that.

Thank God Ive never had crack or opiates except when prescribed for my head on motorbike crash with a car in 1992. As an ex nurse I know the rule abou opiates, and seems to be so. If you take them for pain relief they don’t addict you. But I have known ex heroine addicts and they have all said to me, you never feel as good in the rest of youre life as when you first took heroine.

The argument against the non addiction of opiates not addicting you if they are used for pain relief, is my practical nursing experience. My first nursing ward was children infectious diseases, half of whom were children and young adults with CF, not CF Cronic Fatigue, but cystic fibrosis. Not just CF but those with an infectious disease called cepatia, incurable. In my day a CF with cepacia had one of three outcomes, with equal split. The best chance if you went that route, was made no difference to youre prognosis. The next group, second best outcome had their life shortened by ten years compared to the average cf without cepacia. The third group died within five years.

These poor buggers were addicted to opiates because it relieved their sh1t life. Sadly the consultant used to trick them by giving them a drug which occupied the neural receptors that opiates fit, so the opiates are less effective. Dubious treatment. But nobody said the medical profession does everything right. I never said that.

So returning to drug taking, it isnt true that if you take the drug for pain you arent addicting. It ought to have been qualified only if the pain relief is required for a short time.

After my accident was only a short time. Addicted to enddorphins I am by excercise. But I have only returned to opiates in other periods of extreme pain. So remain not addicted. But people treated long term with opiates are addicts, sorry to say.

So my learning on drug abuse in college is instrumental on keeping me abhorent to addictive drugs. Im in the building trade, it is offered. I quietly decline.

[Paul Barker]

Back on the gm70. Its got no chance right now, but may get built in my lifespan. A long time hence. They say laughter is the best medicine. Following two full days of shear torture in the husband and wife existence where one has dementia. I even said to her I wont be able to carry on looking after you, you will have to go in a home and the children will loose half their inheritance. You dont know how torture dementia is for the loved one compus mentus, so dont judge! Im doing my best. After that terrible time last night we both watched the program about funny things going wrong in tv. I was laughing hilariously at the funny moments which was infectious and we both went to bed in a state of rlief from the past days. Maybe I can survive this?

So Andy’s Man Club didnt help me. Then there was another offer of help. A new manager of the Crescent £ownstairs bar was tood around in the Crescent. I also went there alone after the gym I go to town get a coffee buy bananas and eggs at Iceland to replace the carbs and provide the protein. To save money I stay in public such as The crescent. Scoff the bannanas and the raw eggs. Its just practical. If I eat at the coffee shop its costly. But to be fair lurking in alleys etc to eat raw eggs isnt relaxing for the mind. I was vulnerable and lonely and the drunk new manager invited me down to the cellar saying bring youre bannanas eat them at the bar, come down for friendship we wont mind you eating youre food. Come and. We will cry together if thats what you want.

I went. He bought the drinks he offered me cigarettes, but I gave up smoking. He had to go, he had been a little unusual in behaviour. The barman told me he takes speed. I havent been back. Yes he would help my mental health, but I would have ended up smoking again, drinking regularly again and on wizz. Nah, I avoid the Crescent now. Its a minefield out there.