Frog Tube Preamp Inspired by Alembic F2b

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WOW! Over 10,000 views since July and still going! Thank you all for your interest!

On the Frog Tube Preamp 2.0 DIY PCB, I included a diode clipping option. (you will see a group of 4 diodes on the screenprint of the PCB in the upper right corner). With an on/off/on switch, you can select two different diode clipping configurations. There is no other preamp PCB that offers that. What I never told anybody is that I got the idea from the KLON Centaur overdrive. I placed it within the circuit in a similar way the clipping was positioned in the KLON circuit but added the switching option. It isn't as blatant of clipping as the KLON, but is very much responsive to your pick attack. At first I thought I wasted my time, but I am getting very fond of the option. Be sure and try some red LEDs in one side. They even will light up a little, the harder your attack, so you could mount them in holes in the enclosure. I put 1N4148 in the other side. I also recommended a 10-12k resistor, however, it may be fun to experiment with a 25k linear pot instead of the resistor. Feel free to experiment and let us know what you find out! Thanks. http://Frogpedals.com

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Timko of Kansas City Missouri has this build report on the Frog Tube Preamp PCB, on the madbeanpedals.com forum:

Now that cooler temperatures and shorter days are here, I've found myself getting back in the building game. This was my first preamp pedal, and I only managed to shock myself once! This is Mark Price's Frog Preamp, based on the Alembic F2B, which is based on the preamp section of the late 60's Fender Dual Showman. It's got tons of volume, as well options for added brightness, less brightness, and clipping. I have settled on one set of clipping diodes, the 1N270 (often used in peoples Klon Klones). I'm still trying out the 2nd set of diodes. It's got a traditional Fender tone stack, which seems to match my main Ampeg Rocket really well. There's no footswitch as this is something I have sitting on top of my amp in an always on setup.

The name comes from a 5.0ish earthquake that I felt in my office while I was building it. The earthquake originated in Oklahoma, most certainly due to fracking.

This is a remarkably simple build when comparing it to some of the other monsterous delays and modulation pedals I've built. You need to make sure you order the right components, but once that's done, you can get it put together in a short amount of time. However, I'll give people the advice to cut the flat parts off the bottom of the tone stack pots because they could potentially ground out the capacitors in the tone stack due to the circuit layout. I had this problem, and spent a couple of days debugging it. You may also have to cut down the heat sinks to make it fit (I had to cut the fins off the one I had in there), but they'll still dissipate heat enough to function.

The graphics turned out all right, but I messed up and put the control text too close to the knobs. Aside from that small detail, I'm really happy with the way it turned out. At some point in the future I am going to create a dual preamp pedal (more in the spirit of the Alembic) with a way to jump the channels. I may also remove the mids tone pot from the chain, setting it to a fixed value.

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Almost have this preamp enclosure finished. Getting close! http://frogpedals.com

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First reported completion of a Frog Tube Preamp PCB by "cedrelebarret" of France (on madbeanpedals.com forum):

Hi

I 've finished the 1st part of my project : a preamp with compressor in a 19" 2u enclosure. (It's the reason I did'nt use an in wall transformer ; this transformer will power both the frog and the compressor)
Thanks for your work on this board.

cedric

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I have completed the Gerber (fabrication) files for the Frog Classic Tube power supply and the Frog Bigmouth output section. I plan to submit those to my fabricator tonight. I takes about 1 week for fabrication and 2-3 weeks for shipping.

The Frog Classic Tube power supply is designed to supply the Frog Bigmouth output section with enough power to drive a 12AU7, Ecc82, 12Bh7a or 6n1P dual triode preamp tube from .75 watts to about 2.75 watts. It is laid out just like a Tube amplifier power supply. You can run a Russian subminiature 6n16b as well. The MillMax socket can be used on the Frog Bigmouth section too. I have not tested the output section yet with the Russian subminiature 6n16b, but will soon. I believe the output on that should be limited somewhat compared to standard preamp tubes at around 1 watt. Testing and documentation for both boards to follow. A 12VAC wall transformer with about 1.5 amps capability recommended.

Though my original design for the Classic power supply was to run the Bigmouth output section, you could easily run (estimated) 4 preamp channels with this power supply using the Frog Tube Preamp 2.1 add-on board. The add-on board has all the same capabilities as the Frog Tube Preamp 2.0 PCB except for the diode clipping option and a high voltage power supply. It can be run stand-alone easily as long as the ~185VDC is provided. Remember, I recommend that board be used with pots off-board because the compact size puts the pots physically too close to the preamp tube to be practical. Just some ideas.

I'll keep you posted. THanks! http://frogpedals.com

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This Frog tube preamp is another of my prototypes ( #4) that I made but never had finished the enclosure. This allowed me to experiment with labeling and colors that may be used for my finished production models I hope to be able to sell next year after I get FCC certifications complete. I learned a lot and have some minor changes planned for the next prototype enclosure. Let me know what you think of the finished design and if you would want one of these on your pedalboard! For those of you with a keen eye, you may have noticed in the gut shot that I have developed my own stompswitch true bypass PCB. I will have those available early next year and you will be able to add them on to your preamp PCB orders. Thanks! http://Frogpedals.com

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For the month of December 2016, I will be offering the Frog Tube Preamp 2.0 (with on-board high voltage supply) PCB at 3 dollars off the normal price. You can buy as many as you like! I have sold over 40 boards so far all around the world.

Thank you for making the http://frogpedals.com effort worth all the work!

Mark

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3 more Frog Tube Preamp 2.0 PCBs sent out today! One sent to jean-christophe In France and Two to Michael in Arkansas. 45 sent out worldwide so far! Thank you all! Be sure to post your project builds so we can see them! Frogpedals.com

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Weirdest Frog Tube Preamp 2.0 configuration yet. Started making the enclosure for prototype 5 which is a Russian submini vacuum tube soldered into the PCB and laid over flat. All the switching will have LED indicators. I am trying to figure out the best way to ventilate the heat. Check back as I get this to its production quality look! http://frogpedals.com

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Only a few more weeks to get the Frog Tube Preamp DIY PCB for 3 dollars off. That is like free shipping! Thanks to those that have already ordered. Have a great holiday season. http://Frogpedals.com

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10 Frog Tube Preamp PCBs almost ready for the high voltage power supply testing. After testing I will add the heater power supply and then preamp components. These are being built for my production release of the Frog Tube Preamp Fx1 early in 2017. They will look much like the prototype in the attached photo. Still working out some of the final details. Frogpedals.com

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There is a great little write-up from VMAXVMAX on madbeanpedals.com about the Frog Tube Preamp that he just built

http://www.madbeanpedals.com/forum/index.php?topic=23234.msg238560#msg238560

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I finally started a gallery of photos at http://frogpedals.com/index.php/gallery/. It also includes the start of a customer build gallery. If you have built a Frog Tube Preamp PCB, then send me pictures of the build so I can show it on the website. I am working on being able to give attribution to the owner of the customer build. Probably have to buy the pro version of the photo gallery....

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Sorry I haven't been on too much lately. I am working hard at getting a run of about 10 completed Frog Tube Preamp Fx1 units ready for sale. FCC approval and other "business" related things have been put in place to be able to legally sell these things. You can see some of my drill pics. I drill an 1/8th inch pilot hole for all screws, that helps center the step bit for the final drills. Otherwise, the step bit can wander. Since these will be digitally printed using a UV printer, the holes need to be pretty accurate. See the attached pics. Of course you can still buy the Frog Tube Preamp 2.0 (and 2.1 add-on) PCBs and make your own at any time!.
In other news, I am still waiting on my package from Hong Kong of the Bigmouth output section, Classic power supply and stompswitch board. There is a rumour that they have hit the postoffice (after 2 months!). I'll let you know soon. I won't order from Hong Kong during the holiday season again! I will get them added to the website as soon as possible!

http://frogpedals.com

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Rollie Hallen provided this “labeled” version of the Frog Tube Preamp 2.1 PCB with
Fender tone stack values. He is adding this on as a second channel to an existing tube
amplifier. Green is ground, Red is high voltage, numbers indicate tube socket contact number

http://frogpedals.com

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Well a lot of things have transpired since here last. I have release the Frog Fx1 Tube Preamp Master version, I am working on a stompbox version that should be available within the next few months and have gotten the documentation completed for the Frog Stompswitch PCB. The main thing about this stompswitch PCB besides it is true bypass is that I provided for up to 2 LEDs. If you like a light-plate, you can point one down and the other one up through the enclosure. Or, you can just use one of them. You can look at it at: http://frogpedals.com and click on the PCB products. The wiring documentation for this little PCB is here: http://frogpedals.com/index.php/product-documentation/ scroll down toward the bottom of the page. I am also working on the documentation for the Frog Bigmouth 1-2 watt output section and the Classic power supply. Those are listed on the PCB products page. Whew! alot going on but it is a lot of fun. Let me know if you have any questions. Thanks!

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Maybe you don't need to use this as your own personal sales thread and refer to your website for that ? clearly a business and not a one off!
It makes me not bother checking out the FSB classifieds for the other people, but maybe your contribution to FSB is so great the moderators are o.k. with it
looks like an interesting decent product, Good luck

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It was approved, and it is the area I was told to use. I do appreciate your comments on the items.

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Wow, I am finally starting to catch-up to some of the information I promised some months ago! I have the first version of documentation for the Frog Bigmouth low wattage (1 - 2 watts) output section PCB and "Classic" power supply PCB and some suggestions for implementation. The documentation is at: http://frogpedals.com/index.php/product-documentation/ Scroll to the bottom of the page. I have created a Low Watt Tube amp bundle that includes the "Classic" power supply PCB, the 2.1 add-on Tube Preamp PCB and the Bigmouth output section PCB at about 5 dollars off compared to buying separately. You can access the shopping page at: http://frogpedals.com, go to the PCB products and it is on the last row of products. Regarding the documentation: I will be doing updates over time of that documentation. I need to flesh out the information as I go. In fact I am working on a 1.1 version of it right now (at lunch time!). You will need to download the Frog Preamp 2.1 add-on board documentation for that part. Please ask questions and let me know what other information you would like to have to make your own little studio/bedroom tube amp in an enclosure.
One detail is that I am using a Bud CU-247 cast aluminum enclosure. It is about 7.39x4.703x2.218 in dimensions. Also, there is a specific output transformer I recommend from musicalpowersupplies.com the OT5PP.

Please feel free to ask questions! It will help me better update the documentation. Thanks!

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I have updated the Frog Bigmouth/Classic Power supply documentation for creating a Low Watt Tube amp. It is now version 1.1. I made some general updates, but also added a section on the Cathode Resistor array switching so it can be more understood. This is how you get different power levels out of the installed vacuum tube. Kinda cool and I made it simple to do on the Bigmouth PCB. Go to the documentation here: http://frogpedals.com/index.php/product-documentation/ and scroll to the bottom. You should see the link for the 1.1 version of documentation. Please, let me know any other information you would like! Thanks!
So, for the Low Watt guitar amp, you will need to use the Frog 2.1 add-on preamp PCB documentation and the Frog Bigmouth and Classic Power supply documentation.