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May 25, 2019, 04:13:16 am

Poll

What features would you like to see in a full function preamp? - choose up to five

enough gain for separate LOMC input using FET ($$)
9 (6.2%)
or option for mounting step up transformer for LOMC, ala ErosII ($, but adding xfrmr will cost)
13 (9%)
tone controls (requires extra tubes - $$$)
6 (4.1%)
mono switch ($)
16 (11%)
channel reverse switch ($)
3 (2.1%)
buffered tape monitor out ($$)
3 (2.1%)
two generic outputs ($)
20 (13.8%)
or two outputs, with crossover filter dedicated to use subwoofer amp ($$)
15 (10.3%)
volume and balance pots ($)
15 (10.3%)
or high grade stepped attenuators ($$$)
24 (16.6%)
mute button ($)
5 (3.4%)
SS powered headphone jack ($$)
5 (3.4%)
or tube headphone jack ($$$ more tubes and much bigger)
8 (5.5%)
tone control bypass ($ to add to $$$ tone control circuit)
3 (2.1%)

Total Members Voted: 40

Voting closed: February 28, 2019, 09:26:55 am

Author Topic: Full preamp - what features?  (Read 1131 times)

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Offline Doc B.

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Full preamp - what features?
« on: February 14, 2019, 09:26:55 am »
We are working on a full function preamp design (i.e. a control preamp that includes a phono stage) and we are wrestling a bit with what features to include. Some features are pretty inexpensive to add like extra output jacks, while others can get expensive because things like extra tubes are required.

This poll is a list of some of the features we have considered, with $$$s to indicate how much we estimate said feature will add the the cost. Note that even the least expensive ($) level options will add something to the kit price. Please also note that some things are either/or type choices - LOMC choices, output jack choices, volume control choices and headphone output choices. Please choose one or the other in each category if they are of interest. You can check up to 5 boxes.
« Last Edit: February 14, 2019, 09:40:08 am by Doc B. »
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline denti alligator

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Re: Full preamp - what features?
« Reply #1 on: February 14, 2019, 11:36:52 am »
Cool, is this something that will have a phono pre on par with the Eros II?
- Sam

Rega P3-24 (w/AT 150MLX) w/Groovetracer upgrades / C4S Seduction / FLAC -->J.River -->DSD256 -->Gustard X20 / Stereomour II / Klipsch Forte II w/Crites upgrades / C4S S.E.X. 2.0 +Nickel MQ Iron / Speedball Crack / Sennheiser HD600 w/Cardas cable

Wish list: Eros / Crackatwo / Tode

Offline Alonzo

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Re: Full preamp - what features?
« Reply #2 on: February 14, 2019, 03:10:59 pm »
Hmmmm, lots of options.
Where's the remote control module???
Alonzo B
BeePre, Kaiju, some Stereomours (I's and a II) to DT150 tweeters, FE206/ Eminence 15A's open baffles and a pair of Frugal horns IIIs, and a Mainline with HD800

Offline Doc B.

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Re: Full preamp - what features?
« Reply #3 on: February 14, 2019, 05:25:51 pm »
Hmmmm, lots of options.
Where's the remote control module???

If some of the other features don't turn out to be popular we might be able to work that into the design. But I suspect it could get a little spendy.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline Tubejack

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Re: Full preamp - what features?
« Reply #4 on: February 16, 2019, 12:45:34 am »
Options for XLR inputs and outputs?  (I'd like to see 2 each)
There are 10 types of people in this world,
Those that understand Binary and those that Don't!

Offline pendergast

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Re: Full preamp - what features?
« Reply #5 on: February 16, 2019, 04:47:59 am »
Hi,

This is interesting. Thank you for putting this out here. I'll circle back to the nostalgia piece of the Foreplay II and this project. The challenge for me (and not necessarily for others here) is one of budget: getting the most with the lowest expense without compromising quality. This is obviously a very subjective point of view.

I suppose the kit will be offered with some basics, and upgradable add-ons? Like a basic model with 4 inputs, 2 outputs with switch (to amp of headphone amp), then additional modules (phono preamp, etc.)? I suspect that is a challenging package to create given a diy business model.

Anyway I'll be watching as I am always interested at what you do and still enjoy the 2006 SEX and everything that came afterwards.

Offline Kermit

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Re: Full preamp - what features?
« Reply #6 on: February 17, 2019, 06:03:43 pm »
Does anyone use balance controls?  I’ve had a couple amps with them and never used them.  Was looking at some tube amps by other mfrs, and was surprised to see balance knobs.

What’s the use case?

Offline Raymond P.

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Re: Full preamp - what features?
« Reply #7 on: February 18, 2019, 04:51:44 pm »
I use balance controls to tweak the placement of my center image. I find that my center image can drift. Not sure what causes it, but it varies with what song I'm playing. It's also nice to compensate for any L/R channel circuit mismatches, room acoustics, and maybe my not so symmetrical hearing response. I really like it on the BeePre and use it often.
Raymond P.

Offline Bill Chase

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Re: Full preamp - what features?
« Reply #8 on: February 20, 2019, 03:04:23 pm »
Doc, thanks for the opportunity to provide input.  I really liked that the poll results to date show up after I signed in and voted-- very cool!
Bill Chase
Digital music collection enjoyed thru:
   Mac Mini to Jolida Glass DSD DAC
   BeePre & Stereomour I
   Seductor EL84 Amp
   DecWare Ultra Preamp w 5x Paramount 300Bs with Magnequest Iron
   Crack with Speedball
   SEX v1
Guitars and Ukulele enjoyed by Tode

Offline Kermit

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Re: Full preamp - what features?
« Reply #9 on: February 26, 2019, 08:14:34 am »
That makes a ton of sense- thanks for the explanation!

I use balance controls to tweak the placement of my center image. I find that my center image can drift. Not sure what causes it, but it varies with what song I'm playing. It's also nice to compensate for any L/R channel circuit mismatches, room acoustics, and maybe my not so symmetrical hearing response. I really like it on the BeePre and use it often.

Offline Doc B.

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Re: Full preamp - what features?
« Reply #10 on: February 26, 2019, 09:13:21 am »
Not sure what causes it, but it varies with what song I'm playing.

If everything is consistently off to the right you may have an imbalance. If the singer is to the right on one song and to the left on another, that is a decision made by the mix engineer, i.e., it's supposed to be that way. The reason we put in the balance pot is to compensate for channel mistracking at low level settings. Stereo pots will always have some resistance tolerance error and a corresponding signal level discrepancy from channel to channel, that is usually worst at the lowest settings.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.