I don't want to accidentally brush it with my fingers whilst it's still wet, it's bloody horrible goopy stuff. No better reason than that! And if the cat jumps onto the desk (which she does frequently) I don't want it getting on her, either.
The Newton 300B
- Thermionic Idler
- Old Hand
- Posts: 1018
- Joined: Sun Apr 22, 2012 8:22 pm
- Location: Southsea
#31 Re: The Newton 300B
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
#32 Re: The Newton 300B
Ok, was just wondering. You only need to put very little on anyway.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- Thermionic Idler
- Old Hand
- Posts: 1018
- Joined: Sun Apr 22, 2012 8:22 pm
- Location: Southsea
#33 Re: The Newton 300B
Yeah, I put way too much on. Not once, but twice.
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
- Thermionic Idler
- Old Hand
- Posts: 1018
- Joined: Sun Apr 22, 2012 8:22 pm
- Location: Southsea
#34 Re: The Newton 300B
Further progress today - standoffs and hum bucker pot fitted, along with some of the rear panel-mounted elements including two of the motor run caps. These are what I can put on without blocking access to the transformer mounting holes and covers etc. I've done this on both chassis but from now on I'm concentrating on the left channel amplifier only.
Next up, heater wiring and input transformer.
Next up, heater wiring and input transformer.
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
- Cressy Snr
- Amstrad Tower of Power
- Posts: 10579
- Joined: Wed May 30, 2007 12:25 am
- Location: South Yorks.
#35 Re: The Newton 300B
Looking good so far Dave.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
#37 Re: The Newton 300B
Shoddy!
- Thermionic Idler
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- Joined: Sun Apr 22, 2012 8:22 pm
- Location: Southsea
#38 Re: The Newton 300B
Today, I focussed on this bit of the circuit - specifically the input transformer and its load resistors as recommended in the Lundahl documentation:
Here's the transformer in place and configured 2:1+1, note also the test leads from the Analog Discovery. Takman carbon film resistors and Jensen PIO:
The LL1684 has some pretty impressive measurements. This is the 1kHz square wave response, both phases
And the response / phase shift at 50kHz
Here's the transformer in place and configured 2:1+1, note also the test leads from the Analog Discovery. Takman carbon film resistors and Jensen PIO:
The LL1684 has some pretty impressive measurements. This is the 1kHz square wave response, both phases
And the response / phase shift at 50kHz
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
- Thermionic Idler
- Old Hand
- Posts: 1018
- Joined: Sun Apr 22, 2012 8:22 pm
- Location: Southsea
#39 Re: The Newton 300B
Progress in the last couple of days - the signal circuitry and heater wiring for the input and driver stage is now done.
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
#40 Re: The Newton 300B
Fast work there dave!
- Thermionic Idler
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- Location: Southsea
#42 Re: The Newton 300B
Some more progress. The signal path wiring is basically all done, and yesterday I also tested and set the CCS's to the 29mA value required for the 6V6's. Next thing is the heater wiring on the 300B's and the power supplies.
Sadly it looks like my target of getting both amps built by the end of this week might be missed...
Sadly it looks like my target of getting both amps built by the end of this week might be missed...
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
- Cressy Snr
- Amstrad Tower of Power
- Posts: 10579
- Joined: Wed May 30, 2007 12:25 am
- Location: South Yorks.
#43 Re: The Newton 300B
Ohmite Audio Gold are nice sounding resistors.
Not too costly either.
Not too costly either.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
- Thermionic Idler
- Old Hand
- Posts: 1018
- Joined: Sun Apr 22, 2012 8:22 pm
- Location: Southsea
#44 Re: The Newton 300B
That's good, it's the first time I've used them. Usually I opt for Mills but it starts getting horribly expensive if you use them everywhere, and I already had a lot of parts budget in the eight Jensen PIO coupling caps I needed. This time I just used Mills on the 12SN7 and 6V6 cathodes.Cressy Snr wrote: ↑Thu Dec 31, 2020 11:57 am Ohmite Audio Gold are nice sounding resistors.
Not too costly either.
Did I mention this amp weighs as much as a boat anchor? Thank heavens I didn't include an interstage transformer, seriously if I had I don't think I could have physically lifted the final build. And that's for one monoblock.
I'm probably jinxing myself here, but I think if I get up early and go at it solidly, I may get it finished tomorrow. I tidied up the secondary wiring on the two main transformers today and got those done, also the heater wiring via the humbucker pot for the 300B's is now in place. Part of the issue with using off the shelf transformers is capping off and finding somewhere to secure all that unused wiring so that it doesn't get in the way.
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
- Thermionic Idler
- Old Hand
- Posts: 1018
- Joined: Sun Apr 22, 2012 8:22 pm
- Location: Southsea
#45 Re: The Newton 300B
Finished - and it works perfectly! Voltages pretty much on the button with my Spice model predictions. It sounded a little edgy and congested at first, but bedded in nicely after an hour or two.
Does it improve on the Beasts? Actually, we think it does, but final judgement will be reserved for when the other one is built and we can hear them as a stereo pair. It's quite a close call but there is no mistaking the transparency, clarity and sheer musicality of DHT's done right. It really does sound quite glorious.
More later.
Does it improve on the Beasts? Actually, we think it does, but final judgement will be reserved for when the other one is built and we can hear them as a stereo pair. It's quite a close call but there is no mistaking the transparency, clarity and sheer musicality of DHT's done right. It really does sound quite glorious.
More later.
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
Linestage: Bruno Putzeys Balanced Pre + Hans Polak relay mod, LCDuino control
Power amps: 300B PP 'Symmetric Reichert'
Speakers: FF225WK Big Mets