Search found 8861 matches

by Paul Barker
Sun Mar 10, 2024 4:17 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

Firstly, no more cockups, and no failed parts. Erm…. Brought b+ down to 505. Taken Nick’s points on board. Oh wow it is so good. Yes the cap to b+ contibutes greatly to the project. I highly recommend it. It is cleaning something up, whatever it is. I’ll bring it to the next meet definately! I highl...
by Paul Barker
Sun Mar 10, 2024 4:05 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

OK mounted the new choke and caps. Souldered everything. Now the two smaller caps are an old idea from a Triodeel email forum. The fraction of the mu of the valve of the value of the cathode bypass cap. From cathode to b+. Similar idea to WE ultrapath but injects b+ phase correct to where the signal...
by Paul Barker
Sun Mar 10, 2024 1:24 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

I’ll take you’re experiential knowledge.

Meanwhile the 11uF caps arrived, so a few changes a foot. But not today.

Image
by Paul Barker
Sat Mar 09, 2024 11:10 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

I could put a base plate on as the top, inverted bottles can sit in an oil bath to exceed ratings. Just saying. My friend who used to maintain the 4 or so PYE line amplifiers in the cold war which sent the radio round scarborough. The amps were about the size of an estate car with parallel push pull...
by Paul Barker
Sat Mar 09, 2024 10:18 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

The first picture is B+ not anode volts to arrive at anode volts take 5 off for transformer 50 off for bias, 472v https://i.postimg.cc/WzNmdMbx/IMG-1144.jpg https://i.postimg.cc/zD7S9PxN/IMG-1145.jpg https://i.postimg.cc/k5SvzJpY/IMG-1146.jpg I just wanted tobring to you’re attention a naughty but n...
by Paul Barker
Sat Mar 09, 2024 10:27 am
Forum: Everyones Projects
Topic: OK…so I’m on wi’ summat
Replies: 149
Views: 30707

Re: OK…so I’m on wi’ summat

Mild steel is best for cutting milling punching bending tensile strength weight. Aluminium tears and sticks Copper is heavy and costly also hard to machine sticks too but not as bad as aluminium. I put the 833a amp me and Nick did a joint effort. The copper wasnt worth its added weight. Some people ...
by Paul Barker
Sat Mar 09, 2024 9:26 am
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

I’m very glad to report only the grid choke was faulty this time. Also the valve which was subjected to +75 grid volts has recovered. The bias difference between channels isnt significant. https://i.postimg.cc/pVGRGfT9/IMG-9113.jpg https://i.postimg.cc/XNz6cnHd/IMG-9114.jpg https://i.postimg.cc/xCjV...
by Paul Barker
Sat Mar 09, 2024 8:33 am
Forum: Everyones Projects
Topic: OK…so I’m on wi’ summat
Replies: 149
Views: 30707

Re: OK…so I’m on wi’ summat

I'm no metalbasher Steve, how did you get such a nice corner and straight side at the front? I use a thick chopping board with a machined straight, flat edge. Place the metal sheet on the edge of the kitchen worktop, then place the board on top of the metal to be bent and line it all up with the lo...
by Paul Barker
Fri Mar 08, 2024 10:27 pm
Forum: Everyones Projects
Topic: OK…so I’m on wi’ summat
Replies: 149
Views: 30707

Re: OK…so I’m on wi’ summat

Thanks Steve.
by Paul Barker
Fri Mar 08, 2024 9:37 pm
Forum: Everyones Projects
Topic: OK…so I’m on wi’ summat
Replies: 149
Views: 30707

Re: OK…so I’m on wi’ summat

How much is that good looking sheet of aluminium?

I need to start thinking of the JM70 Monoblocks. Probably four boxes two power supplies two signal sections. Only thing missing is a matched choke. If I find some money could buy a matched pair of Hammonds if they do a big choke for choke input.
by Paul Barker
Fri Mar 08, 2024 9:28 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

The power supply has more voltage available and may get used for other projects. Its a nice quiet variac, so its a handy bemch supply aswell. The rectifier heaters are not via the variac, they have full mains. Thats why I put a mains out takeoff in the variac.
by Paul Barker
Fri Mar 08, 2024 8:53 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

Should be 8 watts possibly 9 watts. Erie how there isnt any power supply noise. Maybe there is something in the Jeremy Epstein finding in the Darling Fest write up. Also the triode pair distortion cancelation may work. Even if I cant get my head round it. I’m thinking it may be better done with a dr...
by Paul Barker
Fri Mar 08, 2024 5:52 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

The power supply is silent. The 11 uF caps from cathode to b+ yet to arive. Probably wont hear any difference. The power is more than enough at home on kef corelli loudspeakers. After Ive permanently fixed it, right now its clip leeded x type coupling cap on right channel 47 nuf, the 2uF pio can go ...
by Paul Barker
Fri Mar 08, 2024 10:14 am
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

Oh WOW as if there was nothing more to go wrong. The right channel choke open circuit. Another brand new valve damaged as I put in two brand new USA made military 6550’s. Lucky I had another grid choke. Now in 7th heaven. AT last once more. https://youtube.com/shorts/FxBeeL1H0bk?si=ZxUBXEuFO2FRZO6b ...
by Paul Barker
Fri Mar 08, 2024 6:13 am
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9384

Re: 6550 SE Amplifier

So life is slow motion, but Ive fitted the 90 uF bypass caps and ordered two 11 uF 600v polyprops for b+ to cathode. Cathode resistors not yet arrived and with more time available decided it was a stupid number 500, and Ive got that many resistors no longer being used, Ive decided to use the 680 oms...