Some words from Salas
Hypnotize DCB1 has been long discontinued. Contrary to the popular Mezmerize complete version of six relay input selection and volume pot placement area, Hypnotize was a single input configuration of the same circuit.
But bigger with heavier raw supply section (large reservoir caps & TO-220 bridge diodes) to can easily support >>200mA hot-rod bias current for its shunt PSU if so desired. Demanding big external sinks in this case. Chassis floor Mosfets cooling stops being and option beyond 350mA or so.
Renders a more immersive soundscape and robustness of tone that way, arguably 10% better in rough terms, thus the law of diminishing returns stands firm.
Regardless, some hot-rod fans asked for Hypnotize to be available as an option again.
Given this opportunity it was reconfigured to even larger (214X106mm) for more reservoir caps (now four positions) and accepting board level sinks for the bridge diodes and Mosfets.
There are two ways to build it. One easier for lowish bias current with no sinks on the bridge diodes, but board level sinks on the Mosfets. By populating the 2X18 Ohm small resistors per side. Dissipation is ~1.6W per Mosfet. Expect about 45C on 50mm tall sinks.
The other way is true hot-rod with one 3.3 Ohm heavy duty resistor per side and external sinks. Dissipation becomes ~5W per Mosfet, constant.
The TO-220 bridge diodes board level sinks should be now employed. Chassis drilling for adequate size external sinks is also now needed.
A 100VA transformer is a better option now while 50VA was very good before. Spec 15V+15V AC secondaries as always with any kind of DCB1.
You can even spend 10W per Mosfet when using one 1.2R 10W setting resistor per side if so inclined.
The keen eyed may spot that the shunt PSU sections have no 2SK170 legends for their JFETs. But simply DGS pin designations. To save on those rare expensive NOS parts since PF5102 has been proven a good replacement there. Lowest IDSS selected for those two next to the 1R resistors. Does not matter PF5102's have DSG pins order since SG are connected together in this design.
In production Linear Systems LSK170A/B, or even modern Toshiba 2SK209GR SMD on SOT23-3 to DIP mini adapter boards can work correctly in the PSU section.
The main audio section JFETs need be of higher transconductance and continue to be the closely matched IDSS 2SK170BL or LSK170B quartet.
Lastly, why I named it FLEXSINK edition you may ask. Either because flexible for sinking choice or because you can flex a hot-rod big sinks DCB1 buffer preamp once again
Regards and happy builds
Salas
---
Notes from Teabag-
The DCB1 FlexSink edition will be offered as as a board for $35.00. The Flexsink board is 2oz copper, 2mm thick, with immersion gold. It is difficult to pull up a trace on the board, and easy to desolder without destroying in comparison with other boards.
Transistor kit only is 55USD
This is the essentials for the board, including 2SK170BL and PF5102 transistors, and all others for the board to be made.
I have put together a kit called "Starter Pack".
This is designed for ease of build, with reasonable, and fine sounding parts kit using Vishay CCF resistors and TDK caps. Transistor kit is included.
The cost is 95USD.
I have put together a more exotic parts kit called "Super Pack". Transistor kit is included.
This uses Nichicon Super-Through and KZ caps and Dale/Vishay CMF/RN type resistors.
The cost is 140USD.
Since the start of the pandemic, useful parts have escalated in price and scarcity. The "Super Pack" kit will likely be of very limited quantity because of parts shortages. Signal wire connectors were removed to save costs.
Private message me for this, or visit the reverb shop to purchase.
Hypnotize DCB1 has been long discontinued. Contrary to the popular Mezmerize complete version of six relay input selection and volume pot placement area, Hypnotize was a single input configuration of the same circuit.
But bigger with heavier raw supply section (large reservoir caps & TO-220 bridge diodes) to can easily support >>200mA hot-rod bias current for its shunt PSU if so desired. Demanding big external sinks in this case. Chassis floor Mosfets cooling stops being and option beyond 350mA or so.
Renders a more immersive soundscape and robustness of tone that way, arguably 10% better in rough terms, thus the law of diminishing returns stands firm.
Regardless, some hot-rod fans asked for Hypnotize to be available as an option again.
Given this opportunity it was reconfigured to even larger (214X106mm) for more reservoir caps (now four positions) and accepting board level sinks for the bridge diodes and Mosfets.
There are two ways to build it. One easier for lowish bias current with no sinks on the bridge diodes, but board level sinks on the Mosfets. By populating the 2X18 Ohm small resistors per side. Dissipation is ~1.6W per Mosfet. Expect about 45C on 50mm tall sinks.
The other way is true hot-rod with one 3.3 Ohm heavy duty resistor per side and external sinks. Dissipation becomes ~5W per Mosfet, constant.
The TO-220 bridge diodes board level sinks should be now employed. Chassis drilling for adequate size external sinks is also now needed.
A 100VA transformer is a better option now while 50VA was very good before. Spec 15V+15V AC secondaries as always with any kind of DCB1.
You can even spend 10W per Mosfet when using one 1.2R 10W setting resistor per side if so inclined.
The keen eyed may spot that the shunt PSU sections have no 2SK170 legends for their JFETs. But simply DGS pin designations. To save on those rare expensive NOS parts since PF5102 has been proven a good replacement there. Lowest IDSS selected for those two next to the 1R resistors. Does not matter PF5102's have DSG pins order since SG are connected together in this design.
In production Linear Systems LSK170A/B, or even modern Toshiba 2SK209GR SMD on SOT23-3 to DIP mini adapter boards can work correctly in the PSU section.
The main audio section JFETs need be of higher transconductance and continue to be the closely matched IDSS 2SK170BL or LSK170B quartet.
Lastly, why I named it FLEXSINK edition you may ask. Either because flexible for sinking choice or because you can flex a hot-rod big sinks DCB1 buffer preamp once again
Regards and happy builds
Salas
---
Notes from Teabag-
The DCB1 FlexSink edition will be offered as as a board for $35.00. The Flexsink board is 2oz copper, 2mm thick, with immersion gold. It is difficult to pull up a trace on the board, and easy to desolder without destroying in comparison with other boards.
Transistor kit only is 55USD
This is the essentials for the board, including 2SK170BL and PF5102 transistors, and all others for the board to be made.
I have put together a kit called "Starter Pack".
This is designed for ease of build, with reasonable, and fine sounding parts kit using Vishay CCF resistors and TDK caps. Transistor kit is included.
The cost is 95USD.
I have put together a more exotic parts kit called "Super Pack". Transistor kit is included.
This uses Nichicon Super-Through and KZ caps and Dale/Vishay CMF/RN type resistors.
The cost is 140USD.
Since the start of the pandemic, useful parts have escalated in price and scarcity. The "Super Pack" kit will likely be of very limited quantity because of parts shortages. Signal wire connectors were removed to save costs.
Private message me for this, or visit the reverb shop to purchase.
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I am not so convinced all users see it. Since transition to new format, there have been lots of questions on where it is.
Your signature is not at the bottom of the post for me so I browsed on to your page and info. It's a little convoluted I must admit.
Michael yes I'm on Android 98% of the time. Can access PC if required but a faff. One we need to flag up!
I found the issue reported already, but no solution.
https://www.diyaudio.com/community/threads/signatures-not-displayed-on-mobile-devices.381856/
https://www.diyaudio.com/community/threads/signatures-not-displayed-on-mobile-devices.381856/
There are several Super Pack kit boards ready at this time. They are in my reverb shop, listed in my signature (only visible from desktop)
The Starter pack and transistor kit only options will be listed later, I currently only have a few boards that I ordered prior to group buy.
The Starter pack and transistor kit only options will be listed later, I currently only have a few boards that I ordered prior to group buy.
Group buy for these boards end in one week on 2-27. Please see links in my signature (not available on mobile) or private message.
Group Buy ends tonight. Please sign up in spreadsheet linked in signature (not visible in mobile, sorry) or private message me with your email and where you live, to determine next steps.
Hey,
Tea-Bag or anyone can tell me that the value's of these 2sk170BL's are matched close enough?
Tea-Bag's handwriting is sometimes a little hard to read but I'm reading:
6.03 or 9.03
7.99
7.98
7.95
Seems that the first one is off by a lot.
Thanks for the help in advance.
Tea-Bag or anyone can tell me that the value's of these 2sk170BL's are matched close enough?
Tea-Bag's handwriting is sometimes a little hard to read but I'm reading:
6.03 or 9.03
7.99
7.98
7.95
Seems that the first one is off by a lot.
Thanks for the help in advance.
Attachments
Thanks so much. That would make a lot more sense. I had a wrong one in there.
Also while I'm here. The 2 matched PF5102's are for the pads that are alone in the center (near the big foil caps) are they not?
Please review the current notes I have for DCB1 FlexEdition. Let me know if you think I should add something to clarify.
https://docs.google.com/document/d/1KnRq5Q1dj_DGaXqZb1pJNmfnV8dFck8nKJ8fzPu1SaA/edit
https://docs.google.com/document/d/1KnRq5Q1dj_DGaXqZb1pJNmfnV8dFck8nKJ8fzPu1SaA/edit
Its a nice set of practical notes along with photos! Maybe add a couple of shots regarding where to probe for rails voltages and DC offset checks.