I have been looking cases ment for A-class amps. I have found one that is good enough looking. It has 90mm x 300mm x 40 mm sinks on sides. So for ubibs, I plan using one side sink (90x300x40) and add another sink (80x300x80)on the other side (two boards per sink).
The second case side sink (90x300x40) is for DCG main board.
SD4309B All Aluminum Power Amplifier Chassis DIY Enclosure HiFi Preamp Case New | eBay
The second case side sink (90x300x40) is for DCG main board.
SD4309B All Aluminum Power Amplifier Chassis DIY Enclosure HiFi Preamp Case New | eBay
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Such cases provide ample cooling for the shunt regs and output stages. They are good.
Maybe the question could be varied:
Do the devices need a certain minimum temperature to be working optimal ? („Can they be too cool to sound good“)
...
No, they can't be too cool to sound good when talking about normal living room temperatures.
Quality and price wise you would be much better with Hi-Fi2000 case. There is a Black Friday 20% discount on standard prices:
Coperchi in ferro 1mm
I’ve made my DCG3 using such case:
https://www.diyaudio.com/forums/ana...g3-preamp-line-headphone-490.html#post6324276
Thank you, Salas!
Thanks Salas. Cost-Benefits-Analysis has started
F
Probably, the cost-effect-balance is not very effective.
Since the rectifiers/diodes/etc. seemingly need a stable surrounding (temperature- and current-wise), and must not be driven above a certain limit, most builds concentrate on the upper limit (must not get above x°C), and focus lies on technical/layout-details.
Even though I'm always tempted by beautiful stuff (http://www.takachi-enclosure.com/data/c16/HYR_02.pdf), I very much like cost-effective, clever solution (like, using the chassis' bottom-plate as heatsink, using best-possible heat-transmission material etc.)
Thanks Tombo56 for reminding me of the Modushop cases, order is in. I see you have used snubbers with those Toroidy trafos. Are they 50va 2x18v? Can you share the values (I think I have the same trafos)?
I see you havent use upa:s, are those 2sk170 BL:s? Have you compared them against upa:s?
And thanks Salas for quidance, I plan to squeeze everything out of this great preamp, lets see how far it takes.
I have a good phono (Vendetta Research SCP-2C) and very dynamic and resolving speakers (Genelec 1038b), and DCG-3 is holding its place really well.
I see you havent use upa:s, are those 2sk170 BL:s? Have you compared them against upa:s?
And thanks Salas for quidance, I plan to squeeze everything out of this great preamp, lets see how far it takes.
I have a good phono (Vendetta Research SCP-2C) and very dynamic and resolving speakers (Genelec 1038b), and DCG-3 is holding its place really well.
Transformers are 2x19V 60VA, because mains voltage is 220V in my area, so I have close to 2x18V with those 230V rated transformers. I’m sure difference to 50 VA transformers is small and same snubber values can be used. I have 10 nF, 150 nF and 16 Ω. For 50VA I would use 18 to 20 Ω. During Quasimodo test, it was almost the same with 16 to 18 Ω.
There was no time jet to compare 2SK170 to uPA as I’m fiddling with the Muses volume control and some other projects.
There was no time jet to compare 2SK170 to uPA as I’m fiddling with the Muses volume control and some other projects.
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I built up a breadboard for testing and fired up the preamp this evening. I have an old pair of Sennheiser PX-100 headphones with no ear cushions (they disintegrated). The DCG3 sounds pretty good. It's very quiet and detailed.
I hooked it up to the living room stereo and had a sense of more speed and less distortion than my Aikido preamp. But it may be too much of a good thing in my system. I need to play with it some more.
I haven't built a relay timer board yet. For now I'm manually operating the relay with a 9V battery.
I have to decide if I want to leave it like this, or move forward with packaging it in a proper box.
Anyway, it's pretty cool. Thanks for sharing your design, Salas.
-Henry
I hooked it up to the living room stereo and had a sense of more speed and less distortion than my Aikido preamp. But it may be too much of a good thing in my system. I need to play with it some more.
I haven't built a relay timer board yet. For now I'm manually operating the relay with a 9V battery.
I have to decide if I want to leave it like this, or move forward with packaging it in a proper box.
Anyway, it's pretty cool. Thanks for sharing your design, Salas.
-Henry
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No, this is all I've got for the moment. The raw supply is a little weak. I was planning on making a better board with more capacitance and snubbers.
I imagine the Jung-Didden regulator has a distinct sound quality. TBH, I don't build gear that often so I don't have a sense of how these things affect sound quality.
Just listening casually with my nude PX-100s, the "PRAT" seems really good compared to plugging into my laptop.
-Henry
I ended up buying a matched quad of LSK170s from the diyaudio store.
I used BC327-40s for the current mirror. I bought twenty On Semi devices from Mouser and built a test jig to measure hfe. They all measured close to hfe = 400 so I just punted and selected two pairs randomly. With the op-amp out of circuit I was able to trim the DC offset to less than 0.1mV and it seemed stable. So I think that's all working as it should.
The potentiometers are Daven stepped attenuators from an old RCA broadcast console. I stripped them and replaced the resistors with metal film parts. The impedance is 100k Ohms, which I know isn't optimal for this circuit. I have an Elma 24-position rotary switch that I plan to build up as a 20k attenuator.
I used BC327-40s for the current mirror. I bought twenty On Semi devices from Mouser and built a test jig to measure hfe. They all measured close to hfe = 400 so I just punted and selected two pairs randomly. With the op-amp out of circuit I was able to trim the DC offset to less than 0.1mV and it seemed stable. So I think that's all working as it should.
The potentiometers are Daven stepped attenuators from an old RCA broadcast console. I stripped them and replaced the resistors with metal film parts. The impedance is 100k Ohms, which I know isn't optimal for this circuit. I have an Elma 24-position rotary switch that I plan to build up as a 20k attenuator.
Salas, what voltage should the ubib power bank c1 capacitors at minimum be when using as DSG-3 psus?
I Can use max 30mm height in my build. Im aiming ”best possible” performance.
What you think about these:
https://www.mouser.fi/ProductDetail.../381LL682M035A032?qs=Cb2nCFKsA8p5ESxxZhKUoA==
I Can use max 30mm height in my build. Im aiming ”best possible” performance.
What you think about these:
https://www.mouser.fi/ProductDetail.../381LL682M035A032?qs=Cb2nCFKsA8p5ESxxZhKUoA==
Well, the cap on the previous post link is obviously wrong size 35x35mm, dont know what I was thinking.
How about this?:
https://www.mouser.fi/ProductDetail/EPCOS-TDK/B41303J7688M?qs=yiCaORDwWV7uD1cvkD054g==
How about this?:
https://www.mouser.fi/ProductDetail/EPCOS-TDK/B41303J7688M?qs=yiCaORDwWV7uD1cvkD054g==
35V minimum rating in a diameter that fits of course. The DCSTB board takes 18mm D 7.5mm pitch paralleled reservoir capacitors. But the Ubib board takes one 30mm D snap in 10mm pitch capacitor. That TDK cap looks decent general purpose. You could also consider LKG1H682MESBAK.