Hahaha! I never knew I was doing dead bug style, just thought I was lazy when soldering components directly together. Now manhatan style is genius. I can see the appeal, especially for this project, should provide some great ground planes and plenty of layout room for some fun caps. Suggestions on, non ridiculously priced, capacitors welcome. I'm definetely going to build dual mono boards 
Hey, there are even Manhattan bits kits: QRPme - QRP FUN in cans, boxes and from scratch!
About coupling caps, steampunk caps would be aesthetically adequate, but in the absence of such outside post-apocalyptic movies there are Russian NOS Teflons in aluminum can for interstage and big green ones K something series for output. The rather affordable PP Mundorfs with some mineral oil inside aren't bad either. They are F1 car tire like in form so they don't take up too much layout length. EVOs & Supreme EVOs they are named. The longer their name the higher the price.
About coupling caps, steampunk caps would be aesthetically adequate, but in the absence of such outside post-apocalyptic movies there are Russian NOS Teflons in aluminum can for interstage and big green ones K something series for output. The rather affordable PP Mundorfs with some mineral oil inside aren't bad either. They are F1 car tire like in form so they don't take up too much layout length. EVOs & Supreme EVOs they are named. The longer their name the higher the price.
I am following the buld notes on the FSP build guide but am a little confused as to what value to choose for R2,R3. The parts list calls for 3.0 - 11.0 ohms to match the IDSS of the 369 transistor used, however, the gain section says to use the value 91R for a 40dB MM build. Should I add the values together or use the gain section value?
A second question has to due with C3 and C4 film cap choices. In the picture, on the FSP build guide, C4 is a 1uf cap where the parts list call for a 2.2uf cap. Adittionaly C3 does not look like 100nF cap either. What's the story here?
Lastly is there any advantage to using two seperate transformers when building the PSU over a sinle torriod with two 36volt secondaries? I'm thinking of using an Antek with a static sheild like this one:AS-2236 - 200VA 36V Transformer - AnTek Products Corp
A second question has to due with C3 and C4 film cap choices. In the picture, on the FSP build guide, C4 is a 1uf cap where the parts list call for a 2.2uf cap. Adittionaly C3 does not look like 100nF cap either. What's the story here?
Lastly is there any advantage to using two seperate transformers when building the PSU over a sinle torriod with two 36volt secondaries? I'm thinking of using an Antek with a static sheild like this one:AS-2236 - 200VA 36V Transformer - AnTek Products Corp
For MM you only use Q1 & R2. Q2 & R3 positions you leave blank. The Gain paragraph in the guide says: "For circa 5mV MM cartridge don't populate Q2,R3, use 91R R2, 5.6K 1W R13, 1.8K R4, for 40dB gain and proper overload margin. Use 100nF C3 only value when with MM. Choose Q1 between channels from a 10.5-12.5mA range at 5% IDSS pair tolerance."
The photo story is I had 1uF C4 because I was mainly using a high input impedance tube line preamp at the time. So to keep the VLF response the same. C3 could have been 47n because it was the MC version and it could be chosen so as well. From the guide again:
"C3 interstage. Use 100nF when your line stage input impedance is below 50K. 47nF is tighter for high impedance preamps but you may still prefer 100nF if looking for a bit rounder bass system synergy."
Not a big advantage the separate cores, just little wider stereo in particularly spatial systems. Independent secondaries with separate raw PSUs come first. The more the VA the larger the magnetic leakage field also, even between shielded types different sizes like the one you linked. Keep it at a distance from the main circuit and the signal cables.
The photo story is I had 1uF C4 because I was mainly using a high input impedance tube line preamp at the time. So to keep the VLF response the same. C3 could have been 47n because it was the MC version and it could be chosen so as well. From the guide again:
"C3 interstage. Use 100nF when your line stage input impedance is below 50K. 47nF is tighter for high impedance preamps but you may still prefer 100nF if looking for a bit rounder bass system synergy."
Not a big advantage the separate cores, just little wider stereo in particularly spatial systems. Independent secondaries with separate raw PSUs come first. The more the VA the larger the magnetic leakage field also, even between shielded types different sizes like the one you linked. Keep it at a distance from the main circuit and the signal cables.
Hi Salas,
So for R1 I should use 91ohms no matter what the IDSS is of the 2SK369 that I use for Q1? I undersatnd for the 40dB build I am skipping Q3 and R3. waht I wanted to know is should I add some resitance to the 91R value based on the IDSS of the 2sk369 I end up using.
Thank you for the explanation on the capacitors! My story now has a set of 1uf Evo film caps for the input on my Aleph J amp
For the PSU i picked a higher value VA since I am considering powering both the phono stage and a Mesmerize B1 buffer preamp with it. I'm going to build th PSU in a differnt chassis. is it worthwhile to further isolate it inside a steel case like this one? CA-100 Steel Cover - AnTek Products Corp
One more question, sorry for having so many, what is the final voltage provided to the circuit by the shunt regulators. I ask since I'll be powering the circuit initally by batteries whie i layout the regulators in stage 2 of my build.
So for R1 I should use 91ohms no matter what the IDSS is of the 2SK369 that I use for Q1? I undersatnd for the 40dB build I am skipping Q3 and R3. waht I wanted to know is should I add some resitance to the 91R value based on the IDSS of the 2sk369 I end up using.
Thank you for the explanation on the capacitors! My story now has a set of 1uf Evo film caps for the input on my Aleph J amp
For the PSU i picked a higher value VA since I am considering powering both the phono stage and a Mesmerize B1 buffer preamp with it. I'm going to build th PSU in a differnt chassis. is it worthwhile to further isolate it inside a steel case like this one? CA-100 Steel Cover - AnTek Products Corp
One more question, sorry for having so many, what is the final voltage provided to the circuit by the shunt regulators. I ask since I'll be powering the circuit initally by batteries whie i layout the regulators in stage 2 of my build.
Ask for a 2SK369BLs pair 5% matched coming from a range between 10.5 to 12.5mA IDSS. No you add nothing to the 91R. The small value resistors chart is for MC builds.
If you want 200 VA for the low impedance its alright, but for these circuits power needs alone its way overkill. Use a separate transfo for the Mez. The voltage levels needed are other and the bridges are differently used. Don't share same secondaries for the Mez and the FSP. Get two 100VA ones and be both happy and royally overspec. Get one 32V+32V for the FSP since mains power is usually closer to 120V in the US than 110V. The Mez uses one with 15+15VAC secondaries.
The steel cans are looking cool but more expensive than the trafos. Naah, just use bit more distance.
Usually about 35V DC regulated.
If you want 200 VA for the low impedance its alright, but for these circuits power needs alone its way overkill. Use a separate transfo for the Mez. The voltage levels needed are other and the bridges are differently used. Don't share same secondaries for the Mez and the FSP. Get two 100VA ones and be both happy and royally overspec. Get one 32V+32V for the FSP since mains power is usually closer to 120V in the US than 110V. The Mez uses one with 15+15VAC secondaries.
The steel cans are looking cool but more expensive than the trafos. Naah, just use bit more distance.
Usually about 35V DC regulated.
Howdy there, I've a question that I suppose fits this thread, involving potential supporting cast for the Simplistic NFET RIAA. I am running one at approximately 61dB on a Denon DL-103 attached to a very capable Kenwood KP-990, With a NAD 2600 power amp into not overly sensitive , but incredible Legend Audio LEG-7000s. There are potential changes but I'll be keeping the LOMC and +/- 150W solid state power amp configuration. What I am looking for is a recommendation for a DIY preamp that plays well with this phono pre and the others in my system. I just completed an 8000 hour apprenticeship and this is the fulfillment of a promise made myself. I considered going passive, but to get up to the 1-1.2V input sensitivity on the NAD, I'm looking to build something which can be configured to about 10dB gain. I do not need remotes or tone controls or pretty lights or VU meters. I want everything that goes into the amp to sum up to great sound. I'm a fan of a wide sound stage and detail. It will share a home with a B1 Buffer for my DAC, whose output will actually be knocked down a hair. I hope this is appropriate, but I love this circuit so much I want it to have a great line stage to compliment it's greatness. Oh, I keep looking at tubes, just keeps happening. Thanks very much for the consideration if you find the time to help me.
This one maybe: Salas DCG3 preamp (line & headphone)
Since you have been looking at tubes: Some quick subjective assessment of DCG3 vs Aikido i.e. a known very good DIY tube preamp
Since you have been looking at tubes: Some quick subjective assessment of DCG3 vs Aikido i.e. a known very good DIY tube preamp
@Salas, Thanks much for your reply. It only makes sense that these two designs should work together. I'll be boning up on the available literature while I wait on my order. I'm very++ excited.
Would you believe it self-healed? I had tried and tested it for days. I left it idle because of a myriad of family bad luck and used an Advent unit I had recently purchased on the cheap for it's MM stage with a Stanton 881 NOS I got my grubby little hands on. Anyway, when I tried your stage again, there were no anomalies, so I hooked up the Denon 103 and gave it a try with flawless results. Coulda' knocked me down. And as good as that Advent and Stanton sounded, that LOMC sounds better in every regard. Thanks again for your patience and help.
rebranded
Thanks TeaBag,
I received a Salas Folded PCB now I am collecting parts.
These Ebay 50 PCS 2SK117-BL K117-BL N CHANNEL JUNCTIONS TYPE TO-92 | eBay
2SK117's appear to be rebranded.
They are way out of specification to be real.
IDSS measures 24.3872mA, transcondance measures 40.28mS.
Thanks DT
Thanks TeaBag,
I received a Salas Folded PCB now I am collecting parts.
These Ebay 50 PCS 2SK117-BL K117-BL N CHANNEL JUNCTIONS TYPE TO-92 | eBay
2SK117's appear to be rebranded.
They are way out of specification to be real.
IDSS measures 24.3872mA, transcondance measures 40.28mS.
Thanks DT
Attachments
If it helps I sourced 2SK117's from this vendor. They checked out.
2SK117-GR Japan-Transistor | eBay
2SK117-GR Japan-Transistor | eBay
Hello, I'm building this RIAA, point by point. It will be two mono blocks.
I can use two UltraBibs, or just one, to feed both channels in parallel.
If two Bibs will be used, I can se one single transformer or just one...
Current is about 10mA each channel, that's a good thing for me.
https://cdn.shopify.com/s/files/1/0289/4153/files/BoozhoundLaboratoriesJFETMCPrePre.pdf?112
Salas, diyers, what do you think it is the best way? No compromises.
Thank you!
I can use two UltraBibs, or just one, to feed both channels in parallel.
If two Bibs will be used, I can se one single transformer or just one...
Current is about 10mA each channel, that's a good thing for me.
https://cdn.shopify.com/s/files/1/0289/4153/files/BoozhoundLaboratoriesJFETMCPrePre.pdf?112
Salas, diyers, what do you think it is the best way? No compromises.
Thank you!
If you will go with two Ubibs but with one transformer, it must have two independent secondaries for Ubibs set at 120mA CC each. They have independent bridge rectifiers they don't work correctly with AC otherwise.
By the way that pre-pre MC input stage circuit looks more like a second stage design, the gate and source pin resistors are going to compromise its noise performance. Look up this one too, it had happy builders reports.:
2SK170 BL MC step up amp
By the way that pre-pre MC input stage circuit looks more like a second stage design, the gate and source pin resistors are going to compromise its noise performance. Look up this one too, it had happy builders reports.:
2SK170 BL MC step up amp
Yes, I'll use two separate secondaries, if one single transformer is used.
I wonder if It is really better with two psu.
I wanted to make this pre pre because I have almost all the parts and it is very simple.
Many people like these phono pre amps from Boozhound.
Thanks for the squematic, anyway, I'll think about that.
I wonder if It is really better with two psu.
I wanted to make this pre pre because I have almost all the parts and it is very simple.
Many people like these phono pre amps from Boozhound.
Thanks for the squematic, anyway, I'll think about that.
Such circuits don't really need overkill dynamic capability or great separation from the PSU side of things. Very small signals they deal with, they don't modulate the rail. They appreciate very low rail line noise / interference. Because of high gain and their almost zero PSRR. Better split after a common channels PSU into two local capacitance multipliers for extra filtering for instance.