Bottlehead Forum
Bottlehead Kits => BeePre => Topic started by: Mnmax on September 17, 2020, 03:01:53 PM
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Hello All
New here. Looking to purchase a Beepree kit and see they are out of stock at this time. I sent an email to enquire about the availability and have not received a response.
I would like to purchase a used unit or have someone assemble a new unit for me.
Does anyone have any knowledge when the kits will be available?
Thanks
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I have to take some responsibility for this certainly! Maybe Doc B. will permit me to divulge a little more than that...
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Hmm ... the BeePre looks to be the only amp "out of stock". A new BeePre is coming?!
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Oh no
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+1
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BeePremium?
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Hmmmm, is it getting a universal power transformer?
Maybe other goodies?
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Ooh, if there's going to be a new BeePre, I hope it comes with a new filament voltage regulator that's more tolerant of mains voltage sag. (Keeping fingers crossed.)
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a universal power transformer?
a new filament voltage regulator that's more tolerant of mains voltage sag.
Just adding my own speculations to the pile. I suspect that most cases of voltage sag could be dealt with a new universal PT. I imagine a redesign of the fil reg circuit would be quite involved - unless there's a drop-in replacement for the LT1085 that has a lower drop-out voltage. I looked for one about a year ago and couldn't find anything -- but they might exist and I just failed to find them.
cheers, Derek
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This regulator would deal with the dropout problem - max 0.7V @ 3A vs. max 1.5V @ 3A for the LT1085. It also costs less than USD 1.00 in small volumes vs. about USD 4.50 for the LT1085. Through hole parts are getting harder to find all the time and this one is a beefy SMT part with 3.4 mm between solder pad centers.
https://www.mouser.com/ProductDetail/STMicroelectronics/LD29300P2MTR?qs=qNIOPWVpczkBu5EEVEXmAg%3D%3D (https://www.mouser.com/ProductDetail/STMicroelectronics/LD29300P2MTR?qs=qNIOPWVpczkBu5EEVEXmAg%3D%3D)
https://www.mouser.com/datasheet/2/389/cd00003208-1795974.pdf (https://www.mouser.com/datasheet/2/389/cd00003208-1795974.pdf)
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Surface mount parts are not in the cards for our immediate future. If we included SMT parts, we would have to solder them down and test them before sending boards out. SMT parts are also a bit annoying to cool. There have been better regulators offered since the 1085 was chosen long ago, and a lot of the higher current regulators seem likely to remain available as through hole parts so they are easier to cool down (thankfully!).
A universal power transformer is indeed part of what's up.
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Cool.
Grufti's post motivated me to look for a sub-1.3V drop-out, 3A+ LDO reg in a TO-220-3 (three leads) package. Still don't see anything. But there is the LT3083 in a TO-220-5 (5 leads) that looks really interesting. Comparing it to the LT1085: Max drop-out voltage of 510 mV versus 1.5V; typical 85 dB ripple rejection @ 120Hz versus typical 75 dB; self generated noise of 40 uV versus what I calculated to be 300 uV @ 10V for the LT1085 (0.003% of output voltage) -- but the 40uV noise of the LT2083 is specified for a 500 mA load, or for 3A at 1V output. So I'm not sure if the noise specs can be directly compared.
Edit - forgot to add the link: https://www.mouser.ca/datasheet/2/609/3083fa-1270364.pdf (https://www.mouser.ca/datasheet/2/609/3083fa-1270364.pdf)
Edit #2: Just skimmed the datasheet again and it appears that you only get the low drop-out voltage if you supply a separate "control voltage" that is at least 1.25V larger than the output voltage. So you need two voltage supplies - the one to be regulated and one to control the regulator. ... way too complicated for me.
cheers, Derek
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Thanks for hijacking my thread.
Now is there anyone out there that can provide an answer to my question.
What is the status of availability for the beepree kit?
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What is the status of availability for the beepree kit?
A replacement is in the works.
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Thanks for hijacking my thread.
Apologies.
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A replacement is in the works.
Now that the weather is cooler, my BeePre is behaving itself. I held off buying one of the variacs I see all over the web that seem to have lots of reliability issues. But it would be nice to have a mod for the original that eliminated my summertime buzzing
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A buck/boost converter with a 120V:6.3VCT transformer setup to add half the 6.3V winding will remedy that issue. I built one that went into a small Hammond box with an IEC in and IEC out that would step up the incoming AC voltage by either 3 or 6 volts. This is enough to prevent regulator issues from the dirty/saggy mains voltage we seem to run into when everyone kicks on the aircon.
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Interesting. Would one of Hammond 166?6 transformers work? If so, would any of them work, or would it need to be be one of the bigger ones like a 166N/Q/S6? I’m not sure what the 30VAC on the secondaries meant on your diagram.
Currently I have my BeePre plugged into an APC Line R 1200 voltage stabilizer set at the 127V position. It only switches taps when voltage drops below 120. My voltage is usually over 120 but drops below that often enough that I’d rather not use the BeerPre without a voltage lift. I get buzz somewhere between 115 and 116V, which is still evidently within spec for 120V mains. The APC is fine other than switching noises when the voltage sags and rises.
Feel free to move this post or PM if this is too off topic.
Brent
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A 166K6 would be ideal.
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Thanks!