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by Paul Barker
Fri Mar 29, 2024 8:31 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

I might make a nickel core impedance matching pair of autoformers so this is a complete 1.9 wat SET amplifier aswell. The autoformers potted with in and out connections to inter connect from output of this driver to speaker wire for every day listening. Call it a energy saving hybrid like the cars.
by Paul Barker
Fri Mar 29, 2024 8:15 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

How about this layout. Imagine the new plain stainless top plate.Items mounted on top as seen. The capacitors same mounting bolt through side as pictured here on the EL34 amp. Two filament transformers and one more choke concealed inside. Rectifiers slow start because indirectly heated. Other than t...
by Paul Barker
Fri Mar 29, 2024 7:25 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

Ordered four 80 uF caps and two 4uF caps for this chassis. Two 80’s for power supply two for cathode bypas the two 4’s are the ultrapath power supply noise cancelling cap from cathode of el84’s to b+. Total cost £50 from same seller I last used who is a UK stockist . Shipping free this size order an...
by Paul Barker
Fri Mar 29, 2024 4:25 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

Ordered a sheet of 1.7mm stainless steel, I’ll cut it to size glue it to the existing top with araldite. Meanwhile all iron to go on top will be cleaned and can sprayed maybe the blue colour one of the choke. I can listen to the present amp while Im building this so I can do a shoddy job!
by Paul Barker
Fri Mar 29, 2024 1:06 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

If I use two of these https://i.postimg.cc/X7wv0xHw/IMG-9170.jpg Instead of this https://i.postimg.cc/yNWBWTPp/IMG-9171.jpg I have indirect heating 6 volt so dont need a dls.10 to delay b+ for the health of the E88cc and can get a cheap 6v transformer ready made. One of those cute little Chinese ones.
by Paul Barker
Fri Mar 29, 2024 11:15 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

That will then leave the gm70 power supply to build and output stage. Seperates I think for easier transport. Then watch out when I get a vehicle I’ll be setting off with it! Noone will be safe.
by Paul Barker
Fri Mar 29, 2024 11:02 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

https://i.postimg.cc/SxbMyjp3/IMG-9165.jpg https://i.postimg.cc/J0ykhk0V/IMG-9166.jpg https://i.postimg.cc/ZYLgPvwF/IMG-9168.jpg So it should all fit to this chassis including its own power supply. The modern polypropylene caps are slimmer the ones pictured are cathode bypas in EL34 amp. I can moun...
by Paul Barker
Fri Mar 29, 2024 8:36 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

You are as usual, right to persist with me.. thank you? It is just much better for my situation, and it has every chance of being a great and powerful amp. A little less heavy. But not a lot less.
by Paul Barker
Fri Mar 29, 2024 8:30 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

Well I am not fighting for that valve :-). But a flat load line does wonders. Yes I see 15v peak to peak and its beyond the requirement and looking again at the el34 there is no saying that is any more linear but requires almost double the input voltage. We cant see the grid lines outside the box, ...
by Paul Barker
Fri Mar 29, 2024 8:28 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

Well I am not fighting for that valve :-). But a flat load line does wonders. Yes I see 15v peak to peak and its beyond the requirement and looking again at the el34 there is no saying that is any more linear but requires almost double the input voltage. We cant see the grid lines outside the box, ...
by Paul Barker
Fri Mar 29, 2024 6:29 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

I was thinking 200v 25ma but I agree more would be better. Hang on I’ll just have a look. Its nearly there, but starting to veer off linear at first sight.(though I havent measured the 2nd, and often its a surprise when I do) But since the EL34 has more headroom within better looking grid lines (di...
by Paul Barker
Fri Mar 29, 2024 5:16 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

That was years ago. I no longer remember what I was working on. I never built it. Shame I didnt take a photo copy of the fresh pages in the Vade Mecum then do my doodles on the copy. But I see what youre thinking. I usually prefer the sound of interstage without a resistor to load it. As I’m not dri...
by Paul Barker
Thu Mar 28, 2024 11:00 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

But I appreciate the suggestions.

GM70 driving GM70 if I had a suitable choke or interstage. But the interstage is OK for EL34 and EL34 is OK in the role.
by Paul Barker
Thu Mar 28, 2024 10:51 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

The driver has to swing 240v peak to peak, EL34 more suitable than EL84 especially the EL84 pinches up more trying to achieve the full drive voltage for full power in the GM70. EL34 fits the need. https://i.postimg.cc/hGTCQQKb/IMG-1183.jpg Not possible to get the drive swing without severe distortio...
by Paul Barker
Thu Mar 28, 2024 10:34 pm
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 42
Views: 971

Re: GM70 Monoblocks’

Well theyre popular on ebay. Someone ‘s using them. Not cheap. Must be good. Probably the demand is they may fit in transmitters.