SSPB.V2 Solid State Preamp Buffer Kit

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tortugaranger

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SSPB.V2 Solid State Preamp Buffer Kit
« on: 23 Nov 2019, 06:06 pm »
I'm pleased to announce that we are introducing a new DIY solid state preamp buffer board kit, the SSPB.V2.

The SSPB.V2 is "bag of bags of parts" kit where every part must be soldered into place on a blank printed circuit board. The kit is the buffer board proper only. It does NOT include all the other elements needed to build a complete stand alone buffer such as enclosure, input/output jacks, power jack, feet, wire, etc.

Some of you may recall that we introduced the solid state LDR300.V25 Buffered Preamp last year. The SSPB.V2 board is an updated version of a similar board we used in LDR300 before it was discontinued. The new design is smaller, has more flexibility and optional features,  and in my opinion sounds even better.

This raises the obvious question of whether we plan on reintroducing the LDR300 with this new buffer board. The simple answer is yes. However the new LDR300 will incorporate several additional changes which we are not ready to talk about yet. Timing of this has not been nailed down yet so for now I'll just say first half of 2020.

The SSPB.V2 buffer kit can now be pre-ordered at a 20% discount. It will be released on Jan 14th. The pre-order price is $199.  If you'd rather buy one fully built and tested it will set you back an additional $100 clams.

More detailed info on the SSPB.V2 can be found here where you can also pre-order one:  https://www.tortugaaudio.com/products/diy-preamp-components/sspb-v2-solid-state-preamp-buffer-board-kit/



« Last Edit: 30 Dec 2019, 06:34 am by tortugaranger »

Benny-x

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Re: SSPB.V2 Solid State Preamp Buffer Kit
« Reply #1 on: 29 Dec 2019, 07:22 am »
Hi Morten.

Can you comment on how this compares to something like the Pass B1R2 buffer? I don't mean to get you talking about another manufacturer's products, but where the B1R2 buffer is a solid bassline for buffer amp performance, so I'd like to hear your take on what different design ideas your buffer has or anything else you might say.

I am currently on the hunt for a buffer board to put into a passive preamp that I want to add VU meters to, so there's no gain requirement, but the question is how to retain all the benefits of the passive preamp and clean signal while getting the visuals of the jumping VU meters~

tortugaranger

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Re: SSPB.V2 Solid State Preamp Buffer Kit
« Reply #2 on: 29 Dec 2019, 03:22 pm »
Hi Morten.

Can you comment on how this compares to something like the Pass B1R2 buffer? I don't mean to get you talking about another manufacturer's products, but where the B1R2 buffer is a solid bassline for buffer amp performance, so I'd like to hear your take on what different design ideas your buffer has or anything else you might say.

I am currently on the hunt for a buffer board to put into a passive preamp that I want to add VU meters to, so there's no gain requirement, but the question is how to retain all the benefits of the passive preamp and clean signal while getting the visuals of the jumping VU meters~

The following items distinguish the SSPB.V2 from what I understand of the B1 or similar buffer designs.

1) 2-stage split voltage power supply - +/- 15V SMPS followed by +/-12V linear. This makes it possible to achieve close to zero DC offset and thus avoid input/output coupling caps.

2) We use an adjustable constant current source with a trim pot on each channel to adjust for near zero DC offset. If things change over time you can always tweak the trim pots to get back to near zero offset.

3) Accommodates an optional op amp gain stage with adjustable plug-in gain modules. Technically this makes it more of an active preamp rather than a true buffer but this is optional and not required. If you want/need gain you can have it. Plus the design is not married to any particular op amp as long as it can fit into an 8 pin DIP. If your op amp of choice is SMD only you'll need an SMD to 8 pin DIP adapter.

poseidonsvoice

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Re: SSPB.V2 Solid State Preamp Buffer Kit
« Reply #3 on: 29 Dec 2019, 10:03 pm »
Morten,

LSK170 JFET or what you have shown in your diagram  :wink: ?

Best,

Anand.

tortugaranger

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Re: SSPB.V2 Solid State Preamp Buffer Kit
« Reply #4 on: 29 Dec 2019, 10:11 pm »
Morten,

LSK170 JFET or what you have shown in your diagram  ;) ?

Best,

Anand.


Duh!  :duh:   Yes it's an LSK170. #dyslexicaudio

happyrabbit

Re: SSPB.V2 Solid State Preamp Buffer Kit
« Reply #5 on: 30 Dec 2019, 03:46 am »
ha !  I actually looked up the LSK107..   super secret jfet  8)

Benny-x

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Re: SSPB.V2 Solid State Preamp Buffer Kit
« Reply #6 on: 31 Dec 2019, 03:23 am »
The following items distinguish the SSPB.V2 from what I understand of the B1 or similar buffer designs.

1) 2-stage split voltage power supply - +/- 15V SMPS followed by +/-12V linear. This makes it possible to achieve close to zero DC offset and thus avoid input/output coupling caps.

2) We use an adjustable constant current source with a trim pot on each channel to adjust for near zero DC offset. If things change over time you can always tweak the trim pots to get back to near zero offset.

3) Accommodates an optional op amp gain stage with adjustable plug-in gain modules. Technically this makes it more of an active preamp rather than a true buffer but this is optional and not required. If you want/need gain you can have it. Plus the design is not married to any particular op amp as long as it can fit into an 8 pin DIP. If your op amp of choice is SMD only you'll need an SMD to 8 pin DIP adapter.

Thanks for your prompt reply, Morten. I also visited your webpage for the SSPB.V2 and laughed when I saw the comments about the B1. Thanks for taking the time to detail your comments here as well.

One part I'm still trying to learn or understand is how to wire the buffers to connect the VU meters. I'm not sure how to assign or "double" an output so that the VU meters are always receiving signal while reducing the impact on the signal going to the actual speaker amplifier/pre-out as much as possible. Could you share any details there?

As for the boards, since my pre is balanced and the VU meters receive V+ and V-, then do I understand correctly that I'll need 2x SSPB.V2 boards?

tortugaranger

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Re: SSPB.V2 Solid State Preamp Buffer Kit
« Reply #7 on: 31 Dec 2019, 01:41 pm »
Thanks for your prompt reply, Morten. I also visited your webpage for the SSPB.V2 and laughed when I saw the comments about the B1. Thanks for taking the time to detail your comments here as well.

One part I'm still trying to learn or understand is how to wire the buffers to connect the VU meters. I'm not sure how to assign or "double" an output so that the VU meters are always receiving signal while reducing the impact on the signal going to the actual speaker amplifier/pre-out as much as possible. Could you share any details there?

As for the boards, since my pre is balanced and the VU meters receive V+ and V-, then do I understand correctly that I'll need 2x SSPB.V2 boards?

Yes, for balanced audio you would need 4 channels so 2 boards.

Audio meters take the AC audio signal and turn it into a DC average. This can be as simple as a single diode (half wave rectifier) or a more elaborate full wave rectifier fronted by a high impedance op amp buffer to isolate the meter from audio signal while minimizing any influence on the audio signal itself. I've personally not worked with meters so I don't know what is available on the market and how much of the isolation/rectification circuitry is embedded as part of the meter. I would recommend you go with a proper buffered/rectified approach.

Here's a link to some basic background info on driving meters - http://objectivesounds.co.uk/articles/driving-vu-and-other-ac-meters/

Cheers,
Morten