ePot.V3 Max & Mini Stepped Attenuators & Preamp Controllers

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tortugaranger

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A close-up pic of the plug-in LDR Attenuation Module for the new ePot.V3 Stepped Attenuator & Preamp Controller. J1 is the audio  input/output header. J2 is the control header. U1 is the EEPROM memory chip that holds the normalized calibration data for the 4 LDRs. The full size ePot.V3 is capable of recalibrating any LDR Attenuation Module while the Mini does not have built-in calibration capability. Therefore a LDR Attenuation Module for the ePot Mini will/must come already calibrated.


craig sawyers

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Hi Morten

Can you connect two ePot MAX's as a balanced attenuator?

Cheers

Craig

tortugaranger

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Hi Morten

Can you connect two ePot MAX's as a balanced attenuator?

Cheers

Craig

Hi Craig,

Yes, the ePot.V3 can handle balanced attenuation by using 2 boards and connecting them together with a 2-wire serial datalink. BTW, we've being doing that with the current V25 board for years now so this isn't something new although we have rewritten the board-to-board communications code for the new ePot.

The ePot Mini won't be ready for balanced initially because it doesn't have all the same communications ports but I believe we'll be able to make it possible with some additional work on the firmware and using the comm port that it does have.

Cheers,
Morten
« Last Edit: 14 Apr 2020, 08:17 pm by tortugaranger »

tortugaranger

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Here's a cool backlit pic of the plug-in discrete attenuator board for the new ePot.V3 Stepped Attenuator and Preamp Controller.
  • 127 smooth as silk volume steps
  • 63 dB range
  • Low noise nickel-chrome thin film resistors
  • No step change artifacts - no clicks, dropouts etc.
  • 60k impedance
  • 10 dB +/- channel balance adjustment range in 0.5 dB increments
  • Totally independent stereo channels
  • Manual and remote controlled
  • Switchable 6 stereo inputs
  • Can swap out discrete module for LDR attenuation module
  • Optional OLED display
  • Available later in May

tortugaranger

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Just a quick update on where things stand currently.

We chewed up nearly all of May so far converting the software from conventional C language to object oriented C++. This wasn't in our original plans but the more I thought on this I felt that NOW was the time to do it since we're in this transition period between the V25 and the upcoming V3. It's never convenient to make big moves with software but since we'd already converted over to a real time operating system why not go the full distance and modernize everything now and get it over with. It will make changes and maintenance much easier going forward and a little pain/delay now will be well worth it later.

This past week we had our first chance to do a sound quality comparison between the ePot.V3 running with the new LDR attenuator and new discrete resistor attenuator. These are plug-in modules and it only takes about a minute to swap one out for the other. The V3 recognizes which type is plugged in so no configuration changes are required.

While not a real-time A/B switching  scenario it was good enough to get a clear overall impression. For the 2 of us who did the listening, there was clear agreement as to which sounded better but we also agreed that the difference was not night and day. Indeed both stepped attenuator types were pleasing to listen to in a passive arrangement.

I'm committed to organizing a tour with the new TA300X.V3 preamp once it's ready and will include 2 preamps in the tour box with one running with LDR attenuation and the other running with discrete resistor attenuation. They won't be marked. Tour participants can try both and opine on the results for all to read.  Looking forward to that.

Meanwhile I expect to freeze the ePot.V3 Max hardware design this week after confirming some last minute changes to the on board power supply configuration. If all goes well we'll be placing production orders for blank boards before the week is out. We will populate the first batch of boards ourselves and then likely have them made completely outside on the next batch after that. The ePot.V3 Mini will be out right on the heels of the V3 Max since the Mini is very much a subset build of the full size Max.

That's it for now.

Cheers,
Morten

tortugaranger

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Hi All,

This is a good time to update you on the development of the new ePot.V3 Max and Mini.

Yes, after calling it the Max and then not calling it the Max, we are calling it the Max. Thank goodness we have that behind us. Max and Mini. Not all that original but you get the idea. Max - bigger more capable. Mini - smaller and lighter and can go where the Max won't fit but can't do everything the Max can.

Ok. So after working with both the Max and Mini prototypes I came to a conclusion and a decision. The conclusion was that the new boards need a higher quality power supply solution. They run on 3 voltages - 3.3V, +5V and -5V. This is different from the V25 which runs on only positive 3.3 and +5V. We tried a quick and easy route to the split +/-5V supply but I'm convinced we can (and should!) do better. In order to do better we're going to need a bit more circuit board real estate. But I don't want  to make the boards bigger. The solution is we are moving all power supply hardware bits off the boards and putting putting them on a separate daughter power supply board that plugs into the back side of both the Max and the Mini. The power supply board is not big - less than half the size of a credit card. The same PS board will be used on both the Max and Mini.

The power board will use a 2 stage approach to all 3 voltages with a custom switching regulator on the front end followed by a low noise linear regulator for an additional 70-80 dB noise suppression of whatever comes out of the first stage. There's a lot of fancy new switching regulator chips available these days which take up very little space but for a price. Instead we're going with earlier vintage switching hardware that's very solid and flexible, but takes up more board space. On the other hand the parts are very very low cost and we're bent on keeping the price down on these new electronic stepped attenuators.

Our next steps with all this is getting updated prototypes for the Mini and Max plus an initial prototype build of the new power board. All of the 1st round design modification work is already done and prototype hardware has been ordered. While the Max and Mini have already gone through the design wringer and are essentially done, the power board may take a couple of iterations (always seems to). All the above will likely chew up most of June. If we're lucky the design work will be frozen in 2-3 weeks and we'll order production hardware with availability in July. That's doable but not making any promises.

Below is a pic showing the ePot.V3 Mini next  to a typical credit card. It's smaller than a credit card. The one in the pic has the discrete attenuator module plugged into it. The smaller new LDR module is sitting next to it for comparison. Both attenuation module types use the same plug-in interface interchangeably. The ribbon cable coming off the Mini is going to our OLED display. The new power supply board will go on the underside of the Mini and will be approximately half its size.  The mini won't get wider or longer but with the power supply board it will get thicker.


Randy

Morten, I don't know what you're talking about, but it sounds and looks pretty cool.   

Is the V3 something I can think about as an upgrade to my V25 balanced version when the time comes, or is this just for DIY fans?

Randy

tortugaranger

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Morten, I don't know what you're talking about, but it sounds and looks pretty cool.   

Is the V3 something I can think about as an upgrade to my V25 balanced version when the time comes, or is this just for DIY fans?

Randy

Yes, the V3 Max will be compatible with the V25. Same width, but shorter so will need different mounting holes but that's no big deal. Same audio interface - pin out. Same OLED display interface.  At some point we will offer upgrades.

tortugaranger

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Hi All,

Good news! A quick note to let you know the new power power board for the new V3 Max and Mini is good to go. We've been running the new power board the last 2 days and it's looking very solid. A couple of minor tweaks to the last prototype and we are poised to order production power boards. Same goes for Max and Mini boards which have already been adapted to fit with the new power board.

With these latest design improvements I'm now quite satisfied with the performance and we can proceed towards production.

What this means is that sometime probably towards the end of July we'll have production hardware and can release the new ePot.V3 Max and Mini boards. The new TA300X preamp models will follow shortly thereafter.

Still quite a lot to do including tweaking the code to cover all the permutations. We now have a unified software code that runs both the V3.Max and V3.Mini boards with either board running with either an LDR or Discrete attenuation module. That same code will eventually also replace the current code for the V25.

More a bit later as we get closer to release.

Cheers,
Morten  :thumb:

tortugaranger

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Hi All,

Just posted an updated detailed overview of the new ePot.V3 Max & Mini announcing release later in August.  It's a good overview that gets into some the finer aspects of these two new electronic stepped attenuator models. The Max is the V3 successor to our current V25 while the Mini is a smaller panel mounted version that can replace any existing volume pot or stepped attenuator.

Here's the link to the overview article. https://tortugaaudio.com/new-epot-v3-to-be-released-soon/

Cheers,
Morten

Hikmer

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So what will one have to buy to get the Discrete and LDR Modules for the upcoming 300x release?  And for how much?

tortugaranger

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So what will one have to buy to get the Discrete and LDR Modules for the upcoming 300x release?  And for how much?

While we haven't set it up yet the 300x model will utilize the ePot.V3 Max board with an LDR Attenuation Module by default with the option to choose a Discrete Attenuation Module instead.....or...simply buy either module type as an additional plug-in substitute. The how much part is being finalized but I expect to have that sorted out in the next week or so.

Hikmer

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Thanks!  Also much apricated in the write up on all the options as it answered many questions I had about the technology involved.   

tortugaranger

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Ok. Here's the anticipated pricing subject to confirmation from suppliers on final configuration.

$299 - ePot.V3 Max. Includes LDR Attenuation Module, loose IR module with 6 inch 3 wire cable. +$25 for Apple remote (essentially retail cost). +$149 for optional OLED display w/ encoder, IR module & cables. Same as with current V25. If you want to opt for the Discrete Attenuation module instead of the LDR type the cost delta would be +$50 per the cost difference of each module type cited below.

$199 - ePot.V3 Mini which of course includes an integral encoder. Other includes/excludes same as Max.

$38 - LDR Attenuation Module (100 steps) | $10 adder to program/calibrate it to specified nominal impedance if being used for Mini and you don't have a Max to program/calibrate it yourself.

$89 - Discrete Thin-Film Attenuation Module (127 steps) - nominal 60k fixed impedance (other impedances may be available down the road). Some may complain about  this price given that thin-film resistors are not very expensive. What is expensive are the analog switch IC's we use in lieu of mechanical relays without which we'd never be able to squeeze everything down into this small a package.

Something we've not mentioned before at all (I think) is that we plan to add the ability to control the V3's by smartphone via Bluetooth. This would require adding a separate HC-06 type bluetooth module which you can pick up on eBay OR Amazon for around $5. The V3 doesn't have a custom socket for this bluetooth module but it does have the 4 signals/pins that allow connecting the bluetooth module to the V3 via a simple 4 wire square pin cable. It would also require a firmware update since we don't have all that ready yet. This won't be available for a few months at least but it'll be a pretty cool feature when it's done. At this point we don't intend to charge anything additional for this added ability. We might stock/sell the bluetooth modules/cable for say $10 but the smartphone control app would be free.

tortugaranger

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Hi All,

I'm please to announce that the ePot.V3 "Mini" Electronic Stepped Attenuator is now available for pre-order for $169 which is 15% off the regular $199 price.

We anticipate an August 10th release date.

More info here: https://tortugaaudio.com/products/diy-preamp-components/electronic-stepped-attenuator-epot-v3-mini/

Cheers,
Morten :thumb:





tortugaranger

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Hi All,

I'm please to announce that the ePot.V3 "Max" Electronic Stepped Attenuator & Preamp Controller is now available for pre-order for $249 which is $50 off the regular price.

We anticipate an August 10th release date same as the ePot.V3 Mini announced earlier.

The key differences between the Max and Mini is the Max is a bigger board intended for chassis mounting, does not have an embedded encoder, has built-in input switching for up to 6 single-ended stereo inputs, has built-in LDR calibration, and has a few additional control interface options not available with the Mini. We are still in the process of putting together detailed product documentation on all of that.

More info here: https://tortugaaudio.com/products/diy-preamp-components/electronic-stepped-attenuator-epot-v3-max/

..and here: https://tortugaaudio.com/new-epot-v3-stepped_attenuators-to-be-released-soon/

Features of the ePot.V3 Max include:

* Input switching between 6 inputs via very low noise analog switches
*LDR (light dependent resistor) attenuation module
*.....100 step attenuator
*.....-60 to 0 dB
*.....adjustable impedance 1k to 100k | 20k default
*.....built-in LDR calibration system
*.....plug-in replaceable module
*Optional alternative discrete resistor attenuation module
*.....127 step attenuator
*.....-63.5 to 0 dB
*.....60k fixed impedance
*.....plug-in replaceable module
*Smooth stepping with no sonic artifacts
*No mechanical parts in the signal path
*Remote controlled (Apple infrared remote)
*Manual control via rotary encoder
*Chassis mounted
*Smooth muting/unmuting
*Left/right channel balance w/ reset (+/- 10 db)
*Optional status LED
*Optional high contrast menu driven OLED display with encoder & IR receiver
*2.7" wide by 4.4" long x 1.5″ deep
*Solder pad or pin header for connecting audio input/output

Cheers,
Morten

The ePot.V3 Max is shown below with an LDR attenuation module installed on the left and a discrete LDR module shown on the right. The Max board shown in this pic is an earlier prototype - some minor changes were made in the production board.

We expect to have much better set of production hardware pics in about a week or so.

The second pic shows the relative size differences between the Mini and Max together with the 2 different types of plug-in attenuation modules.




tortugaranger

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Re: ePot.V3 Max & Mini Stepped Attenuators & Preamp Controllers
« Reply #36 on: 18 Jul 2020, 03:31 pm »
Hi All,

We've stood up the initial version of the hardware manual for the new ePot.V3 Mini. The link is below. This manual covers the hardware end of things but does not get very far into how the controls work which will be covered in a separate operation and control manual which is being worked on.

https://tortugaaudio.com/docs/epotv3-mini-hardware-manual/

tortugaranger

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Re: ePot.V3 Max & Mini Stepped Attenuators & Preamp Controllers
« Reply #37 on: 2 Aug 2020, 02:06 pm »
Hi All,

We've started production on the new ePot.V3 Mini and Max stepped attenuator/controller boards this past week. Woo hoo! Work continues on  polishing the firmware but it's the nature of software that it's never done....just shipped. The V3 Mini will likely get released first by mid-August followed shortly thereafter by the V3 Max. We'll be sending out a detailed newsletter on all that later in the week.

I plan to have a new set of pics by the end of the week showing the production hardware in more detail.

We are currently taking discounted pre-orders for both the Mini and the Max per the links below.

Pre-order your Mini: https://tortugaaudio.com/products/diy-preamp-components/electronic-stepped-attenuator-epot-v3-mini/

Pre-order your Max: https://tortugaaudio.com/products/diy-preamp-components/electronic-stepped-attenuator-epot-v3-max/

tortugaranger

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Re: ePot.V3 Max & Mini Stepped Attenuators & Preamp Controllers
« Reply #38 on: 10 Aug 2020, 05:19 pm »
Hi All,

First round of production pics of the ePot.V3 Mini Stepped Attenuator/Preamp Controller are in!
Hear ya go.  :thumb:








tortugaranger

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Re: ePot.V3 Max & Mini Stepped Attenuators & Preamp Controllers
« Reply #39 on: 24 Aug 2020, 06:39 pm »
The "ePot.V3 operation and controls" document has now been posted in our "Docs" section on the website. The document explains how the controls work for both the V3 Max and Mini.

https://tortugaaudio.com/docs/epot-v3-operation-controls/