Dieselpunk Preamp of Doom and the Beast with Two Backs

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Thermionic Idler
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#16 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Thermionic Idler »

Jensen JT-11P4-1TB balanced bridging line input transformers arrived today for the power amps - also got a first order of parts from Mouser on the way, but still quite a few to go. Redesigning the chassis' slightly.
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
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Thermionic Idler
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#17 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Thermionic Idler »

More bits arrived today from RS and HiFi Collective. Farnell order due tomorrow. The biggest order will be from Mouser and I need to make sure I have the budget before I submit that one. This exercise is a bit like herding cats, especially with fluctuating stock levels and the Owston deadline to meet.

A sprinkling of (as much as I hate the term) boutique parts from HiFi Collective for the Beasts along with the 6 PCB valve sockets I needed - I am aware of BR's exhortations that you can use washing machine quality parts for building the amps, but I do still feel the need to pay some attention to what is used where, without going excessively overboard. ClarityCap ESA's were selected for the coupling caps on the basis that they are Made in Britain, affordable, and aren't too big for the circuit board! Takman metal films should do for most of the half-watt resistors. On the output stage, Kiwame 5 watters for the triode strapping, Arcol carbon comp grid stoppers (pack of 25 from RS), and the Mills wirewound 5 watt anode load resistors that I also used on the Son of Beast build.

I'm also planning to use proper ultrafast rectifiers in place of the standard ones listed for the power supply, but those are coming from Mouser. The electrolytics have been selected more for durability (rated to 105C) - given the amount of pre-prep work that's already gone into these things, I want them to last a long time.
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
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#18 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Cressy Snr »

Looking fwd to reading about his project Dave. :)
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#19 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Mike H »

ClarityCap, Kiwame and Arcol CC ooh yeah! Image
 
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#20 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Thermionic Idler »

The part that I'm most worried about is soldering the OPA1612, OPA1632 and OPA1611 opamps onto the A24 boards - these chips are miniscule, smaller than a ladybird. In fact the AMB boards in general look to require more 'brain surgery' skill than the Transcendent one. Will probably populate the Transcendent boards first, then move on to the AMB ones.
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
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#21 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Mike H »

I would use DIL sockets?
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#22 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by pre65 »

Mike H wrote: Wed Mar 15, 2017 12:23 am I would use DIL sockets?
Same here. :)
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#23 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by SteveH »

Bit awkward with smd ics. :D
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#24 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by pre65 »

SteveH wrote: Wed Mar 15, 2017 9:16 am Bit awkward with smd ics. :D
If they are SMD then you need help.
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#25 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Mike H »

Oh crap.

So far I've just managed to solder 1W SMD resistors. That's stressful enough.
 
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#26 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by simon »

If they are surface mount, I've found if I apply solder to one pad first then carefully press the component to the solder pad and reapply the iron so the component drops on to the board as the solder melts then soldering the other pads is fine. Just make sure you don't move the component before the solder's cooled... Use fine solder if you can, and good glasses!
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#27 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Mike H »

Thing I'm most worried about is, cooking the chip if it takes too long. :(
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#28 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Thermionic Idler »

Yeah, I'm trying not to think about it too much. Here's the circuit board in question:

Image

Just imagine that, but really, really small.

I have good glasses, and a magnifier lamp, and two sets of "Helping hands" and another magnifier. No coffee before the soldering. Having looked at the video Ti Kan linked to, I think I have it figured out.

Anyway, the remaining cats have been herded. Big order to Mouser, and a littler order to Digikey, were made tonight for the remaining parts. I'm now committed. Just got power transformers, the billion and one EL509S output valves, chassis work and miscellaneous hardware to go.

The orders to these 5 different suppliers were all done with the help of a very complicated spreadsheet I built, where I entered parts prices / availability, together with price breaks if one bought > 10 or whatever. It would then select supplier based on lowest price. I figured I'd have to go to more than one supplier anyway as not everything could be bought from just Mouser or RS. Took probably a good 4 - 5 months to populate it all, and of course prices moved over the course of doing it, so not sure how accurate the end result was but I reckon the effort saved me over £100 on the build cost.

So here is where I find out whether my spreadsheet worked everything out accurately, or whether I'm about to sink into a clusterf**k of completely wrong quantities of each part...
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
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#29 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by simon »

Mike H wrote: Wed Mar 15, 2017 7:34 pm Thing I'm most worried about is, cooking the chip if it takes too long. :(
I haven't had a problem (fingers crossed). Everything's so small it takes little more than a touch of the iron to flow the solder.
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#30 Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Post by Nick »

Make sure the iron is hot enough. That way it only needs to be in contact for a second.
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