Search found 15788 matches

by Nick
Fri May 17, 2024 10:18 pm
Forum: Valves
Topic: Dying Rectifier?
Replies: 26
Views: 468

Re: Dying Rectifier?

Looks like the GZ33 was the guilty party. Incredible but true! :shock: I've just looked up GZ37 prices. Blimus! And I looked up the GZ33 data sheet. Mea culpa. Yes, a GZ37 is actually less hungry in heater current than a GZ37. I've just looked at eBay. 2 x NOS Mullard GZ33, original boxes, 'never u...
by Nick
Fri May 17, 2024 5:29 pm
Forum: Valves
Topic: Dying Rectifier?
Replies: 26
Views: 468

Re: Dying Rectifier?

Well, you may find a lot of switching noise on the heater. There is no free lunch when it comes to AC to DC, you only get the full 1.414 times with no load.

And you have the voltage lost across the bridge diodes Vf as well to deal with(out)
by Nick
Fri May 17, 2024 9:40 am
Forum: Valves
Topic: Dying Rectifier?
Replies: 26
Views: 468

Re: Dying Rectifier?

I think he means a DIN rail relay socket. This sort of thing https://uk.rs-online.com/web/p/relay-sockets/0402147
by Nick
Thu May 16, 2024 10:11 pm
Forum: Valves
Topic: Valve amplifier service
Replies: 200
Views: 98595

Re: Valve amplifier service

Or as said you could use Audacity to generate test waveforms, I have done similar.
Yep, but not ideal for square waves, very dependent on your DAC and you wont get the fast risetime that we want to push the amplifier.
by Nick
Tue May 14, 2024 2:20 pm
Forum: Speakers
Topic: TG "The Loudspeaker" Build (Sort of)
Replies: 168
Views: 16471

Re: TG "The Loudspeaker" Build (Sort of)

Though the 25kg H&S limit must be in danger!
Image
by Nick
Tue May 14, 2024 1:25 pm
Forum: Valves
Topic: Valve amplifier service
Replies: 200
Views: 98595

Re: Valve amplifier service

Or £1.31 if you just need something simple. https://www.switchelectronics.co.uk/products/ne555-adjustable-duty-cycle-pulse-frequency-square-wave-signal-generator-module-1?variant=45334951264565&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_cam...
by Nick
Tue May 14, 2024 9:10 am
Forum: Valves
Topic: Valve amplifier service
Replies: 200
Views: 98595

Re: Valve amplifier service

Dave reports the amp sounds "wonderful" and has been stable so far. Phew! I cant help thinking that if such a radical change in the level of feedback has not broken the amp (in one or another way) then the original value was in fact wrong. Did you check the original value to make sure the...
by Nick
Tue May 14, 2024 9:06 am
Forum: Valves
Topic: Valve amplifier service
Replies: 200
Views: 98595

Re: Valve amplifier service

Yes, exactly that.
by Nick
Tue May 14, 2024 9:04 am
Forum: Speakers
Topic: TG "The Loudspeaker" Build (Sort of)
Replies: 168
Views: 16471

Re: TG "The Loudspeaker" Build (Sort of)

Yes very interesting. I can't help thinking that getting an adequately balanced platter, with suitable thickness, roundness and centrality would be exceptionally difficult for DIYers though. Unless I missed something, that why I said plinth. I was thinking of what the l07-d was made like "The ...
by Nick
Mon May 13, 2024 8:44 pm
Forum: Speakers
Topic: TG "The Loudspeaker" Build (Sort of)
Replies: 168
Views: 16471

Re: TG "The Loudspeaker" Build (Sort of)

For a few years now, I have been messing around with epoxy granite for vibration damping.
Sounds like it would be a ideal material for a turntable plinth.
by Nick
Sun May 12, 2024 9:16 pm
Forum: Your Fave Artists
Topic: What Are You Listening To Right This Minute?
Replies: 6180
Views: 1952643

Re: What Are You Listening To Right This Minute?

Dave the bass wrote: Sun May 12, 2024 9:13 pm
Nick wrote: Sun May 12, 2024 8:58 pm
Dave the bass wrote: Sun May 12, 2024 7:39 pm I've been after this at a sensible price for years.
I had forgotten about that (and lots of other things TBH).
Like this too? :) ...All 414 pages of it, looking forward to getting stuck into this one.
Image
Nope, didn't even know it existed :-). Do now.
by Nick
Sun May 12, 2024 8:58 pm
Forum: Your Fave Artists
Topic: What Are You Listening To Right This Minute?
Replies: 6180
Views: 1952643

Re: What Are You Listening To Right This Minute?

Dave the bass wrote: Sun May 12, 2024 7:39 pm I've been after this at a sensible price for years.
I had forgotten about that (and lots of other things TBH).
by Nick
Fri May 10, 2024 5:23 pm
Forum: Valves
Topic: Valve amplifier service
Replies: 200
Views: 98595

Re: Valve amplifier service

If it was me, I would want to run some FR plots of the amp and see how it behaved with square waves. You may find the cap in the feedback network may need playing with as well.
by Nick
Tue May 07, 2024 3:03 pm
Forum: Buying and Selling
Topic: WANTED: Windows 7 laptop with working USB port...
Replies: 9
Views: 726

Re: WANTED: Windows 7 laptop with working USB port...

Maybe a Virtual Image would be a better way of doing it? Oracle Virtual Box seems to work just fine with USB integration from outside to inside the VM.
by Nick
Mon May 06, 2024 8:57 pm
Forum: Valves
Topic: Valve amplifier service
Replies: 200
Views: 98595

Re: Valve amplifier service

But decreasing the ratio from 200:1 (to say 22:1) will increase the amount of negative feedback.