Search found 15693 matches

by Nick
Sat Mar 16, 2024 12:21 pm
Forum: Solid State
Topic: Germanium Amplifier
Replies: 162
Views: 79753

Re: Germanium Amplifier

Just for reference, it's pretty much based on this - the 'Burns Orbit', which was a guitar amp apparently - I think -
What I love about that circuit is how much you can see valve thinking. Its basically a valve amp circuit with lower voltages and transistors.
by Nick
Fri Mar 15, 2024 6:46 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 104
Views: 8482

Re: 6550 SE Amplifier

I dont hear any 2nd so maybe the ecc88 is cancelling the worst of it? Answeers on a postcard.
I find in the absence of test kit, the clarity (or lack of) of the voice in this is a good measure.

by Nick
Thu Mar 14, 2024 8:32 pm
Forum: Assorted Stuff
Topic: Road vehicle fires.
Replies: 157
Views: 113407

Re: Road vehicle fires.

The reality of search engine algorithms means that just linking to something from another site increases its score. Increasing its score increases it's perceived value. And so on.
by Nick
Thu Mar 14, 2024 3:13 pm
Forum: Assorted Stuff
Topic: Road vehicle fires.
Replies: 157
Views: 113407

Re: Road vehicle fires.

Not sure if it's facts or conspiracy but possibly worth a listen, it just seems to me a funny world when an edited royal photo can make headlines for days and these events are seemingly covered up rather quickly? Or, you know, its neither facts or conspiracy, just someone on YouTube finding he can ...
by Nick
Wed Mar 13, 2024 2:44 pm
Forum: Beginners
Topic: Pot Impedance
Replies: 3
Views: 278

Re: Pot Impedance

No, the only reason for 100k is if its driven by other valve kit, that source may have a high output impedance so 100k would work better. No reason why 10k won't be just fine assuming your sources is happy with that.
by Nick
Wed Mar 13, 2024 9:03 am
Forum: Everyones Projects
Topic: GM70 Monoblocks’
Replies: 4
Views: 275

Re: GM70 Monoblocks’

Image

38W @ 0.03% THD, £5 + Heatsink and power supply.

Just saying :-)
by Nick
Tue Mar 12, 2024 8:32 pm
Forum: Assorted Stuff
Topic: Nothing In Particular
Replies: 16428
Views: 4478770

Re: Nothing In Particular

Works for me.
by Nick
Tue Mar 12, 2024 2:31 pm
Forum: News
Topic: Paul Messenger
Replies: 2
Views: 402

Re: Paul Messenger

Yep, a genuinely nice guy.
by Nick
Tue Mar 12, 2024 8:48 am
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 104
Views: 8482

Re: 6550 SE Amplifier

Even without the 1.414/0.9 = 1.57 excess voltage, I was thinking more about the cold start condition of the ECC88 that will see the entire B+ on its anode until it starts to pass current.
by Nick
Mon Mar 11, 2024 9:55 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 104
Views: 8482

Re: 6550 SE Amplifier

Would need at least a 5W zener, but yes I guess so. But remember Max, adding some solid state may cause all manner of demons to fly out :-). A potential divider before the first stage would do the job, a 88 doesn't need a 80k load resistor, especially if its got a choke in there as well. Or just lea...
by Nick
Mon Mar 11, 2024 9:48 pm
Forum: Solid State
Topic: Germanium Amplifier
Replies: 162
Views: 79753

Re: Germanium Amplifier

Just a couple of thought, you are never going to be able to use much in the way of negative feedback in that amp (at least by comparison with a modern direct coupled circuit. That interstage is going to add so much group delay and general phase shifting nastyness that the most you can manage is PP v...
by Nick
Mon Mar 11, 2024 9:56 am
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 104
Views: 8482

Re: 6550 SE Amplifier

They are your valves, so up to you. I manually turn heater supplies up then b+. Two outputs on the variac, all heaters first, then b+. I always assume a unexpected short term power outage could happen, so I either make sure that the startup control is automatic, or not needed. The chokes arent inste...
by Nick
Mon Mar 11, 2024 9:07 am
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 104
Views: 8482

Re: 6550 SE Amplifier

Just remember the max anode voltage (cold) of a ecc88 is 550v.
by Nick
Sun Mar 10, 2024 9:36 am
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 104
Views: 8482

Re: 6550 SE Amplifier

can sit in an oil bath to exceed ratings. Exactly how much difference would that make? I would have expected that most of the heat from the anode was dissipated as IR (it being in a vacuum and all that) so how directly is the envelope temperature related to the max dissipation? I suppose it would a...
by Nick
Thu Mar 07, 2024 10:45 am
Forum: News
Topic: Paul Messenger
Replies: 2
Views: 402

Paul Messenger

Will be missed, One of the good ones.