845 Monoblocks,
#1 845 Monoblocks,
Keeping this new thread in context, as a follow up reply to my statement on the Owston thread, claiming the Slagle AVC was not delivering the same Bass Quality, equivalent to the Bass being produced when the 845 amp is being driven by the source, and the inbuilt balance controls on the amps are used to adjust volume.
Nick asked
"What's the input impedance of the 845 amp" ?
I have spoke to the engineer, he has told me it is 50K input impedance, I think he also said the output resistance and input impedance are a match, giving me a brief description on how to measure the output resistance using a multimetre.
Nick asked
"What's the input impedance of the 845 amp" ?
I have spoke to the engineer, he has told me it is 50K input impedance, I think he also said the output resistance and input impedance are a match, giving me a brief description on how to measure the output resistance using a multimetre.
#2 Re: 845 Monoblocks,
Ok, just wanted to check it wasn't too low for the AVC's, but 50k is fine.
I would be interested to know how you can measure the output impedance of the AVC's with a multimeter. Apart from anything else, the output impedance will depend on the impedance of the source and the volume setting.
I would be interested to know how you can measure the output impedance of the AVC's with a multimeter. Apart from anything else, the output impedance will depend on the impedance of the source and the volume setting.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#3 Re: 845 Monoblocks,
Well if the conversation included having a signal generator to drive the pre-amp , then one could imagine ( as you would ) that two alternative loads ( eg. 1M and 20k ) could be put on the secondary and the multimeter used to measure voltage.
"Once you find out ... the Circumstances ; then you can go out"
#4 Re: 845 Monoblocks,
IslandPink wrote: ↑Wed Jun 27, 2018 8:25 pm Well if the conversation included having a signal generator to drive the pre-amp , then one could imagine ( as you would ) that two alternative loads ( eg. 1M and 20k ) could be put on the secondary and the multimeter used to measure voltage.
Yes, but that would only measure the output impedance when driven by the signal generator. You would have to perform the operation with the actual source.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#5 Re: 845 Monoblocks,
There is a mix up into the device the engineer discussed with me.
We only spoke about the 845's , there was not a discussion about the methods of measuring the AVC.
As I said, I "think" the output resistance and Input impedance on the 845's are a match, a explanation of how to measure the output resistance using a multimetre was offered. I was told to expect a reading of 47-50K. The instruction to achieve this reading on a multimetre was not understood by myself.
In the short term, I can keep it simple, I'll bring the AVC as well to Owston, and a listen will confirm my assessment, as being accurate or not.
We only spoke about the 845's , there was not a discussion about the methods of measuring the AVC.
As I said, I "think" the output resistance and Input impedance on the 845's are a match, a explanation of how to measure the output resistance using a multimetre was offered. I was told to expect a reading of 47-50K. The instruction to achieve this reading on a multimetre was not understood by myself.
In the short term, I can keep it simple, I'll bring the AVC as well to Owston, and a listen will confirm my assessment, as being accurate or not.
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#6 Re: 845 Monoblocks,
Umm... maybe I should have made it clearer that the sig gen would feed in its signal before the final stage driving the AVC.
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#7 Re: 845 Monoblocks,
Are there any photos of these 845 amps ?
The only thing necessary for the triumph of evil is for good men to do nothing.
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G-Popz THE easy listening connoisseur. (Philip)
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G-Popz THE easy listening connoisseur. (Philip)
#8 Re: 845 Monoblocks,
Had a play in a few editing softwares, I got there with the correct sized attachment.
The 845's taking their first steps in the Big, Wide, World. Ahh ar'nt they cute.
The 845's taking their first steps in the Big, Wide, World. Ahh ar'nt they cute.
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#9 Re: 845 Monoblocks,
They mean business !
Can we get a close-up ?
Can we get a close-up ?
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#10 Re: 845 Monoblocks,
Best I can do tonight
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#11 Re: 845 Monoblocks,
They were rather good at Owston.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
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#12 Re: 845 Monoblocks,
Photos of the insides please
#13 Re: 845 Monoblocks,
Got to respect the designer on that one. He has used his own circuits, and some are not in use in any other amp.
He assured me if anything happens to him, all the design notes and schematics are mine.
He assured me if anything happens to him, all the design notes and schematics are mine.
#14 Re: 845 Monoblocks,
what's it got in it's pocketses.....
There's nowhere you can be that isn't where you're meant to be
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#15 Re: 845 Monoblocks,
Fair enough John. Not much new in the valve world though.