DoDog,
If I were dyslexic that would be ???? LOL
Glad you made the decision to build this preamp. I've had mine Hot-rodded for quite some time and it improves the "Punch" and "Staccato" in recordings.
Make sure you've got some good heatsinks on those transistors and that they don't get hot. Are you going to build it like Omishra and I did? With the SSP?
Welcome aboard. Friend!
The first caps should work just fine.
Ron
If I were dyslexic that would be ???? LOL
Glad you made the decision to build this preamp. I've had mine Hot-rodded for quite some time and it improves the "Punch" and "Staccato" in recordings.
Make sure you've got some good heatsinks on those transistors and that they don't get hot. Are you going to build it like Omishra and I did? With the SSP?
Welcome aboard. Friend!
The first caps should work just fine.
Ron
I'm just going to do a 200 mA hotrod so I'll use the case for sinking (with pads in-between, of course). Shouldn't be an issue. Don't know that I'll use the SSP, I think I'll just stick with the Mez board as-is. I haven't read of any complaints of a lack of gain using this as a buffer. My only concern would be my MC phono preamp but that's never been lacking compared to a CDP, squeezebox, etc.
I'm in the slow process of designing a case (well, front panel anyway) via Front Panel Express. I'm created the graphics in Inkscape and will import as an HPGL layer, then I'm carefully laying out all my holes. I tend to create the labels, save them off as an SVG then print off. Then I change my mind and try something else. I'm terrified to commit to a final piece.
I've been using a a SSP and a LSA setup for some time and it's nice, but I want to try this build and make it look a bit nicer than a drilled-out Hammond enclosure. Nothing wrong with the latter, I have 5-6 projects in those boxes, but I splurged on a 4U case from the store for my Aleph J build (not started yet) and I want the preamp to look just as nice.
Hi Salas,
My best friend listened to the DCB1 pre in comparison to a Vincent preamp. Naturally he wanted one too! But he wants it in a 5.1 configuration 🙂
so:
I am going to build a 5.1 preamp with 4 DCB1 boards 🙂
Do you know where I can get the real deal fets for this? Ebay has lots of the LSK/2SK/SK170 fets, but I guess most are just fakes.....
Any help would be great!
Thanks!
Sjoerd
My best friend listened to the DCB1 pre in comparison to a Vincent preamp. Naturally he wanted one too! But he wants it in a 5.1 configuration 🙂
so:
I am going to build a 5.1 preamp with 4 DCB1 boards 🙂
Do you know where I can get the real deal fets for this? Ebay has lots of the LSK/2SK/SK170 fets, but I guess most are just fakes.....
Any help would be great!
Thanks!
Sjoerd
lsk170 and any other of the lskxxx are very likely to be genuine.
It's the obsolete Toshiba devices that are being faked.
It's the obsolete Toshiba devices that are being faked.
Chassis arrived today! Woo-hoo ... no more bare PCB and transformer sitting on my audio rack! 😛
As you can see, there is a lot more than a Mesmerize in here. The blue PCB is a remote volume and input selector with LCD display that I will use to control the relays and Alps pot on the Mesmerize. The other 2 PCB's on the bottom right are a Marsh headphone amp and a CCS-fed shunt regulator for it.
The last piece of the puzzle is a logic circuit controlled by the headphone jack's switch that controls relays for the HA power supply and the preamp output to switch between OUT and headphone so it mutes the RCA outs when the phones are plugged in.
As you can see, there is a lot more than a Mesmerize in here. The blue PCB is a remote volume and input selector with LCD display that I will use to control the relays and Alps pot on the Mesmerize. The other 2 PCB's on the bottom right are a Marsh headphone amp and a CCS-fed shunt regulator for it.
The last piece of the puzzle is a logic circuit controlled by the headphone jack's switch that controls relays for the HA power supply and the preamp output to switch between OUT and headphone so it mutes the RCA outs when the phones are plugged in.
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Craig, very nice layout. One of my next projects is to get my DCB1 into a chassis and I'm looking at a similar approach to yours. I want to build in a remote volume and input selector. Whose remote board did you use? I'm looking at various ones like the MV04 on ebay that provide both a knob on the outside of the chassis and remote capability.
Eric
Eric
I used the Analog Metric Kit but ONLY to control my Alps Blue Velvet and the relays on the Mezmerize board. The Analog Metric utilizes an Alps pot that uses the same motor as the Blue Velvet but is a lower quality pot. The relays are active low just like the Mezmerize, so compatible there as well with the audio signal never needing to leave the Mezmerize PCB. If you want a knob also, just add a shaft extension to the pot.
I think I blew my DCB1 
The offset is now - 330mV and - 520mV for the left and right channel. it always was very close to zero.
I was hot swapping the outputs of the DCB1 between amps and saw some static electricity or something...
Anyone same experience?
Maybe lowering the output resistor from 220 Ohm to 10 Ohm wasn't a great idea also....
Walter
The offset is now - 330mV and - 520mV for the left and right channel. it always was very close to zero.
I was hot swapping the outputs of the DCB1 between amps and saw some static electricity or something...
Anyone same experience?
Maybe lowering the output resistor from 220 Ohm to 10 Ohm wasn't a great idea also....
Walter
I once got a severe static discharge to my chassis as I went to change sources and it damaged the amp/follower jFETs just enough to knock their output offset off slightly. Reported in one of the DCB1 Threads.
They recovered over the next couple of days to within a few mVdc of what they were.
I never changed them and now a couple of years later, they are back to normal.
BTW,
as is usual for me, all my Power Amplifiers are all AC coupled. No danger to speakers other than the very loud crack at that discharge moment.
Another BTW,
I regularly discharge to my Mez case and now I never (fingers crossed) hear any "crack", just feel the tingle.
They recovered over the next couple of days to within a few mVdc of what they were.
I never changed them and now a couple of years later, they are back to normal.
BTW,
as is usual for me, all my Power Amplifiers are all AC coupled. No danger to speakers other than the very loud crack at that discharge moment.
Another BTW,
I regularly discharge to my Mez case and now I never (fingers crossed) hear any "crack", just feel the tingle.
Thanks, they didn't recover to normal...
Replaced them with new, super matched ones: 8.58 and 8.61 mA and 8.64 and 8.67 mA, with the lower ones being the CCS and the DCB1 sparkles again!
Lucky I have a few to match from...
The black background, big and deep soundstage, the magical JFET sparkle, it's all back 🙂
Offset is even better then before: 0.4 mV and 0.5 mV😀
Replaced them with new, super matched ones: 8.58 and 8.61 mA and 8.64 and 8.67 mA, with the lower ones being the CCS and the DCB1 sparkles again!
Lucky I have a few to match from...The black background, big and deep soundstage, the magical JFET sparkle, it's all back 🙂
Offset is even better then before: 0.4 mV and 0.5 mV😀
Just curious, I wonder if anyone has compared the 2sK363 to 2sk170 in the DCB1.
The former's higher transconductance should mean lower DC offset (assuming
an equally well-matched pair.) Are there any other advantages or disadvantages?
Thanks,
Dennis
The former's higher transconductance should mean lower DC offset (assuming
an equally well-matched pair.) Are there any other advantages or disadvantages?
Thanks,
Dennis
Lower THD due to higher Yfs and narrower bandwidth due to higher Ciss. About DC offset, matched Idss criterion stands the same although such high Yfs JFETs tend to be even more temperature susceptible than K170.
Hi,
Looking for Matched quads of 2SK170-BL.
How many pieces would I need to buy, to come up with 2 matched quads?
I see 50 Pieces for $33 and 20 for $13, on ebay..
Thanks!
ADD: For Mesmerize, Toroid Tranformer over EI?.. In real listening world, will the Toroid be advantage?
Looking for Matched quads of 2SK170-BL.
How many pieces would I need to buy, to come up with 2 matched quads?
I see 50 Pieces for $33 and 20 for $13, on ebay..
Thanks!
ADD: For Mesmerize, Toroid Tranformer over EI?.. In real listening world, will the Toroid be advantage?
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On Ebay most 2SK170s are very suspicious for fakes these days. Minimum 20 genuine ones would be needed, 50 for top of the crop Idss matches, very slim chance for real ones to get any cheap. There is the diyA store with unmatched LSK170s, there is FetAudio.com Spencer from Singapore matching real ones, one Ebay guy Alweit in Israel who sells matched quads that enough people said they are real, USA guys Ed LaFontaine & Tea-Bag here with several key parts, but I don't know if they have enough matched quads to support builds outside their mini-kits. Better pm them.
Good EI can be better in primary's isolation than toroid, its not a big amp to count weight and heat toroid advantages, so no worries.