Bottlehead Forum
General Category => General Discussion => Topic started by: Dr. Toobz on September 19, 2011, 05:29:01 PM
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Just curious: if Bottlehead would make your dream kit, what would it look like? For example, a tube-buffered DSD dac? An all-tube analog tuner? Or, an 833 SET? I thought it would be fun to hear what other people secretly wish BH would offer as the next "official" kit (even if we know there is no possibility!).
My wish isn't all that crazy: I would readily pony up for a Stereomour-type integrated amp kit that used 300B tubes for 8W output, single ended, with choked DC filaments, a shorting headphone jack, active plate loads, three inputs, a stepped attenuator volume control, and selectable impedance OPT's. Sort of like a SEX amp, expect with 8W output of DHT goodness.
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OTL SET preamp and OTL SET amps. 1000mW is enough for the latter. Of course with SR and active loading. I love my Paramounts. There's no better amps in the world. But I'd love to try OTLs ala Doc and PJ.
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I would love to see an active crossover for Klipsch Heritage speakers.
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OTL SET preamp and OTL SET amps. 1000mW is enough for the latter. Of course with SR and active loading. I love my Paramounts. There's no better amps in the world. But I'd love to try OTLs ala Doc and PJ.
Ah yes, this one interests me. The elusive element is a modern speaker with an 800 ohm voice coil. Anybody have a pair of Philips 9710AMs?
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The active crossover is a great idea! How about a music server?
Doesn't need to be too complicated and would be a good precursor to the BH DAC.
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I would love to see an active crossover for Klipsch Heritage speakers.
Yes, active crossover! Somebody was talking using Quickie as a base for an active crossover.
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We will be redesigning the active crossovers in the Bottlehead system soon, and perhaps a kit will spin off as a result.
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Here's a pair of those Phillips... http://www.audioasylum.com/forums/hug/messages/15/158003.html Of course you could always just add 10:1 step-down errrr.... transformer :-).
Here are a pair of top plates from FPE for an active 12AU7-based XO experimental platform. Stereo input, up to 4 pairs of outputs, 2 octal VR's and a PGP8.1. The PGP has a 6.3V@2mA heater secondary, so in practice, it should be good for up to 6 12AU7's with AC heaters or 3 with DC heaters. Hoping to get away with AC, of course. Anyone want a copy, I'll send a file.
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Here's a pair of those Phillips...
Only the -AM version is 800 ohms. They were mostly 8 ohm, with a few 400 and 800 ohm versions. They also came with or without the whizzer, so quite a variety of "Philips 9710" models.
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Crack build went well, it's quiet and sounds great. Seduction build went well and it's quiet and sounds great.
FPIII build is going well so far. My wish list, only one thing ... please let it be quiet :-) ... if so, Im sure it will sound great.
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How about speakers again?
I do realize the issue with a speaker being developed then the drivers going out of production or changing specs. That is very frustrating I am sure.
We are talking "Fantasy" however.
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How about speakers again?
How about plasma headphones? They could come with a bottle of sunscreen for your ears and one of those fan hats to blow away the ozone. ;^)>
I would like to do a from the ground up speaker development, see my comments about 800 ohm drivers above. We will need some serious investors to support all of the R&D you guys are asking us to do!
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How about a true tube DAC, not only use tubes in the output stage but replace the microprocessor/s with tubes as well. You could call it the EniDAC, probably cost half our national debt and might fit in a room the size of an average basement. Seriously, I would like to see a 300B based headphone/integrated amp kit. Something similar to the Cary amp or the Chinese version Grant Fidelity sells.
Shawn P.
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Early tubed computers took up a whole building and didn't have the processing power of a PC today. I'm not sure this could fit into the Bottlehead base. Not even a really, really big one. (carrying the joke a little further)
How about a true tube DAC, not only use tubes in the output stage but replace the microprocessor/s with tubes as well. You could call it the EniDAC, probably cost half our national debt and might fit in a room the size of an average basement. . . .
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John Swenson and I talked through what would be involved in an all tube DAC, with me being the lunatic and John being the voice of reason. The biggest issue was the amount of power required for all the heaters and heat produced. I think I figured we could fit it on a couple of large relay racks. All those flip flops would take a lotta tubes, and then you would have to hire those ladies in June Cleaver dresses to change out the tubes.
Here's a conceptual image of the power supply
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.tcf.ua.edu%2FClasses%2FJbutler%2FT389%2FENIACrear.JPG&hash=3c439c0600012279b40684dafcd26cbb7ca31eed)
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LOL! Reminds me of the line in "Apollo 13", when the Jim Lovell character is conducting a tour of civilians, and talks about a future with computers that will fit into a single room...
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Sooooo, what is wrong with a women in tight skirts, heels and pearls vacuuming? Is that an option for the kit????
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Are the pearls necessary?
My wish would be to bring back a speaker kit. Maybe a La Scala type with 100+ efficiency or a full-range, single-driver bass reflex (or horn). A metronome-like design would be simple to glue together, but maybe awkward to ship. I bet you could get the forum community to help with the design (I would do what I could) and Bottlehead could do the packaging. I think a lot of people could manage the glue up, sanding, and finishing but probably lack the table saws and hole-cutting gear to do the other work. It could be the Linux of the speaker world. Community designed and tweaked but centrally distributed.
Also, you could bring back the Bottlehead model. I'm not saying that's what sold me on buying my first kit but then, it sure didn't stop me.
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This would be a quite a departure from Bottlehead products, but I would like to see an amp with the same sort of input selection and volumn control as the Stereomour, but with an output of around 60 watts that could handle speakers such as the Vandersteen Quatro. Probably a KT88 based. Point to point with high end components such as all nickel output tranies and obbigato or simular upgraded caps. High end resistors and volumn control. Everything top shelf. Hey, it is just my fantasy amp, so be kind.
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This would be a quite a departure from Bottlehead products, but I would like to see an amp with the same sort of input selection and volumn control as the Stereomour, but with an output of around 60 watts that could handle speakers such as the Vandersteen Quatro. Probably a KT88 based. Point to point with high end components such as all nickel output tranies and obbigato or simular upgraded caps. High end resistors and volumn control. Everything top shelf. Hey, it is just my fantasy amp, so be kind.
It would be great to see Bottlehead offer a nice high quality push-pull integrated. There's a bit of competition from the Dynaco kits and Audio Note, but I think a unique offering would be well received.
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I would like to see a bottlehead tuner kit. Mostly becuase there doesn't seem to be much information on attempting a DIY tuner for FM reception, and I know you guys would make a good one.
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a sub $500 microphone preamp would be an amazing Bottlehead entry into the pro audio world... which has quite deep pockets and a taste for DIY
would love a kit or two aimed at studio applications - tempted to build a foreplay just so I could run some mixes through it... I want to run some program material through my Crack and re-record it but to do it properly I'll have to build a box like the one I use for guitar amps - https://taweber.powweb.com/weber/masslite.htm
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Mic preamp - what functions are needed? A Seduction, deprived of RIAA, is all the amp you need; we've been using one with a B&K measuring mic for years. It's all the gain switches, impedance choices, proximity filters, etc. that gets expensive and fussy. Got an example of a minimalist mic pre that's on the market? Does it need to be rackmount?
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I would like see a 1-5 watt guitar amp with headphone output! Maybe just as a head unit? My roommate would be grateful of this one. :)
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Ah yes, this one interests me. The elusive element is a modern speaker with an 800 ohm voice coil. Anybody have a pair of Philips 9710AMs?
That's interesting but as nice as those philips can sound I doubt they can deliver the resolution and dynamics I love from my current setup. What I'm looking for is something for my current speakers. They're about 106 db per watt efficient and I triamp. Ever since I saw the following PJs post I've been dreamin' about it:
I do think a true zero-feedback Class-A SET OTL could be made with a single 6C33 for each channel. It would consume about 100 watts per channel, and produce no more than 1 watt per channel. I'd expect it to sound awfully good, in fact.
It would be something like a big boys Crack!
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a few commercial examples as requested:
http://www.mercenary.com/vt1vactubmic.html
http://www.mercenary.com/alltub40dbmo.html
http://www.mercenary.com/rmstubule.html
not tube but a respected (and cost-effective) minimal solid state design - http://www.fmraudio.com/rnp.htm
my picks for a minimal design - some of this might be a given but I'll spell it out anyways -
XLR in, balanced TRS out
switchable +48v phantom power
input polarity switch
input attenuation (switched -15db pad would be enough, variable is much nicer)
variable gain (6-12 stepped is nice but not necessary - notice that the Manley linked above is only 5 steps)
Hi-Z unbalanced input for use with electric guitar/bass (I'm curious how much this 'active DI' would add to the cost of the design?)
signal and clip indicators
rackmount isn't completely necessary but that would be a big step towards making such a Bottlehead product very studio friendly - a 1/2 rack form factor that is optionally rackable or desktop is, in my opinion, the approach most likely to find a home in project as well as professional studios - 2 channels of a particular preamp flavor in 1 or 2 rackspaces high is very desirable to many studio owners.
and . . . here are my votes for extra features beyond the bare bones -
variable input impedance
unbalanced insert jack
VU Meter
but really it doesn't need much at all... I have a solid state mic preamp within spitting distance of me right now that besides the in/out jacks only has a gain pot, a clip LED, and a phantom power switch
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I would like see a 1-5 watt guitar amp with headphone output! Maybe just as a head unit? My roommate would be grateful of this one. :)
Same here - I've been wanting a small guitar amp for some time now. There's a couple of kits out there, but they all seem to be designed for sticking in a cabinet, and they're not cheap. Luckily, though, these appear to be very simple to do on one's own; a 12ax7 gain stage (with the second half of the triode used as a regulator or some other freebie function) and an EL84 pentode would net about 4-5W, single-ended.....plenty for headphones and a small speaker. The problem for those of us who live in apartments is fabricating a chassis. That's a big reason why I like Bottlehead's kits so much: everything you need for a complete amp is already there.
Count me in for a Bottlehead guitar amp!
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I do think a true zero-feedback Class-A SET OTL could be made with a single 6C33 for each channel. It would consume about 100 watts per channel, and produce no more than 1 watt per channel. I'd expect it to sound awfully good, in fact.
It would be something like a big boys Crack!
Ok, Xavier, you have nailed my wish list there. I have the tubes and the sockets.
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Hmm, I dunno about that 1 watt 6C33 thing. Sounds like three years of research for two sales. Maybe that could be a free design we put up on the site for DIY. But a small guitar amp, yes. I've been playing with some ideas for a while now. I believe the electric guitar on the new Jacqui Naylor album Lucky Girl (which is being released on Tuesday) might have been played through a protoype of mine. I'll know more when I see Art Khu next week. I think we will begin working on my latest guitar amp idea after we get the DAC finished up.
Re mic pres: when the option list starts to climb you have to let me know how much you want to pay. That will have a big influence on how many gadgets are added. My suggestion might be to forgo a complete rack cabinet and build it all on a front panel, with a simple Hammond die cast box on the back for shielding - roughly like tipping a seduction up on one side. I've laid out a rack style guitar amp design like this, with the tubes set back from the face, and it looks pretty cool. The full cabinets that we use for the Tube Repro and Tube Phono are very expensive.
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Not to mention a new transformer. Look at the specs for the two filaments in each 6C33C-B.
Maybe just an SET using that tube.
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Come on Grainger. What side are you on?
Besides I was gonna buy three kits so it was four, not two!
Seriously in the long term that's something I want to try.
Following a friend's advice my next system won't have iron or CFs, Right now I have to concentrate on my WOT 437A preamp.
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I think that would be a WAF 437A amp (with auto former) ;^)>
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1. DAC (have been eagerly waiting a few years on this one)
2. KT88 or similar based amp 25-50ish WPC (not holding my breath)
3. Tube crossover
4. A TT kit would be fun
5. An active step up for phono stages would be nice as well
6. New speakers. I'm working on a slot loaded, semi open baffle line array and a 3 way, front loaded PPSL. So if you would just do the engineering for me it would free me up for more scuba diving and weekend track days. Not to mention the GAF on the pile of speakers sitting around is getting lower by the second.
And I would really like PJ to get on the flux capacitor thing. Would make it way easier to buy nice tubes if we could just go back in time and buy them new.
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I'm chipping away this weekend at repackaging our prototype DAC for RMAF. It's not what the final one will be, but it should have a lot of the same nutritional goodness. I am indeed glad that I won't be responsible for your suffocation regarding the making of yet another PP 6550 amp in a saturated market. But we do continue to think about higher powered amps.
I think the active step up is about 80% worked out, with a prototype or two in operation. Tube crossover may happen depending upon some upcoming research and results thereof. TT kit would be fun. Unfortunately it's a tough one to do well, inexpensively. Speakers - talk to me in a bit. Working with Mr. Blumenstein on some ideas.
Re the flux capacitor, I'm selling them on ebay.
http://www.ebay.com/itm/120780999047?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649 (http://www.ebay.com/itm/120780999047?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649)
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I am indeed glad that I won't be responsible for your suffocation regarding the making of yet another PP 6550 amp in a saturated market. But we do continue to think about higher powered amps.
What about a single-ended 6550/KT88? What would be really cool is to do an integrated SEP/SET amp that not only straps the pentode to triode with the flip of a switch, but includes typical Bottlehead goodies like active loads, carefully-chosen components, high-quality irons, a shorting headphone jack, etc. to help the amp sound better than it normally might in pentode mode. (I've actually heard that KT88's sound good in a SEP configuration, if done properly, but I've never heard one wired that way, only PP). That would give builders a nice-sounding, 4 or 5W SET amp with the option of flipping a switch to SEP mode to double the wattage and/or get a different type of sound, depending upon one's speakers.
Ditto for an EL84-based amp, which I do know sound very good single-ended.
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Another for an EL84 based guitar headamp with an optional headphone output.
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ssssly,
Your numbers 1, 3 and 5 are either in the works or talked about. Number 4 has been done and was abandoned a few years back. It was a very nice looking table and it might still be marketed. Doc would know.
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Re the flux capacitor, I'm selling them on ebay.
http://www.ebay.com/itm/120780999047?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649 (http://www.ebay.com/itm/120780999047?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1586.l2649)
Could be interesting in a Pmour or FPIII power supply.
ssssly,
Your numbers 1, 3 and 5 are either in the works or talked about. Number 4 has been done and was abandoned a few years back. It was a very nice looking table and it might still be marketed. Doc would know.
Indeed, and I am eagerly following the progress.
How's the Eros coming along?
And the breath holding is an overused scuba phrase. More concerned about exploding than suffocating. But you can rest easy on either account. The market is very saturated. Just prefer to spend my hard earned money in the Bottlehead camp.
A Bottlehead Blumenstein combo would be very interesting indeed.
A plasma tweeter kit would be nice. Never got my attempt working properly and abandoned it for other things.
Any take on active interconnects?
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I'm going slow with the Eros.
I made a pair of unshielded interconnect, KACG, active shielded interconnects using "Zippertubing." All it took was a 6V wall wart, two short pieces of shielded Zippertubing and a 6k resistor for each tube to limit the current to 1mA. It worked but was awfully awkward. I did change the current in steps up to 7 or 8mA and higher current shielded better.
http://www.zippertubing.com/
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Here's a little more brainstorming on the OTL power amp.
As the Bottlehead reference system has gotten more refined we have been finding limitations with transformers, but also with cathode followers. And we have long felt that paralleled tubes have limitations when pursuing the highest degree of resolution, and so does feedback in general. OTLs keep coming up, to get around the transformer problem. However, the fact is that no tube has a low enough impedance to drive an 8-ohm speaker with a reasonable damping factor, without resorting to heavy feedback or massively parallel tubes. And I mean heavy; a cathode follower is not good enough. In addition, in order to get more than a watt you need more current than any practical tube can supply.
Both problems can be addressed with parallel tubes. Here's an example:
The 6AS7 or 6080 can have a plate resistance as low as 280 ohms according to the specification. Since cathode followers and other feedback approaches are out, that would be the output impedance. An 8 ohm output impedance would give a damping factor of 2 into a 16-ohm speaker, and would require 35 triodes in parallel. A stereo pair would be 35 tubes, drawing 8.75 amps at 135 volts, for a total dissipation of 1181 watts. Heater power would be another 87.5 amps at 6.3 volts, or 551.25 watts. Of course, if you are avoiding transformers you probably don't want to use plate chokes, so figure another 350 watts or so for the current source plate loads. For this, you'll get ideally 150 watts out; in practice due to the inability to find a set of 35 matched 6080 tubes you might get 100 watts - of parallel tube sound. The chassis plate could be as small as 20 square feet. You'll need a separate 20- or 25-amp circuit just for the amp.
This does not sound to me like a Bottlehead amp at a Bottlehead price. If anyone has a spare $10k-$15k to build one as an experiment, it would be interesting to find out whether it sounds OK or not.
At lower power, you need feedback to get the output impedance down. I must have been thinking of that when I suggested a single 6C33 for a 1-watt amp. That could be much easier to build - but, again, with heavy feedback it will not reach the highest level of resolution. I suppose we should try it; at least it won't be as expensive as the massively parallel approach.
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Thanks Paul,
Your original post mentioned zero feedback and that's what got me excited. Massive feedback cools me down a little bit. Sounded too good to be true. At least in paper!