gauging interest in a low cost tube preamp

BillB · « **on:** 10 Feb 2009, 01:18 am »

I have been working on this project for a couple weeks and I am pretty happy with the results and I actually have a rev2 in the works already (this mod will run the tube at <50% for all parameters and should lead to very long life).

It is a common cathode design utilizing the 6j6 tube. I chose this tube for a couple reasons:
1) It has a dual triode with single cathode...perfect for the design
2) It is CHEAP!

The preamp is very simple, a relatively low ripple SS power supply, metal film 1% resistors throughout, and low cost capacitors. It has 3 inputs and 2 outputs.

The parts cost total around $175 and I am willing to build them for $250.

I have several options planned that will bring the performance up from 2nd system/desktop performance to fullout main system duty.

What does it sound like?

It is not as detailed as a Manley Shrimp or Aikido tube pre (and would you really expect it to for the cost?) but has a fair amount. Sound stage is not as 3D as my reference pre (Aikido 24v) but is very wide with good center focus. Mids are nice and warm while highs and bass are detailed and accurate.

I feel this is an excellent addition to the office or bedroom system for those looking for some extra inputs and some nice tubey warmth for their digital amps.

"Production" models will use an aluminum chassis for better flux rejection and ease of drilling. They will be painted flat black.

Size is 10"x6"x2"

cujobob · « **Reply #1 on:** 10 Feb 2009, 04:53 am »

This is really cool, Bill! If I had extra cash atm, I'd be down...this is something you just don't see on the market, a cheap tube preamp.

What would the approximate cost be for a Level 3 assembled unit with BEM sides?

BillB · « **Reply #2 on:** 10 Feb 2009, 01:09 pm »

Prices rise really fast...$470 with the wood.

Note that the increase is all parts cost, no additional labor is charged.

BillB · « **Reply #3 on:** 12 Feb 2009, 01:36 am »

Apparently there is no interest in something like this?

Make some suggestions please, I have seen so many of these cheap tube pres end up being nothing but fuzz boxes. This is the real deal, a real B+ voltage (210v) and real gain (13.9dB), not some laptop power supply supplying heater voltage and actually providing - gain.

We can make this thing exotic and pretty but that is going to blow the price through the roof.

I am willing to offer a kit or maybe even sell plans and tubes (I have a bunch).

Whatever it takes.

boead · « **Reply #4 on:** 12 Feb 2009, 01:53 am »

There are allready a few well established, praised manufacturers making amps and preamps that sound many times better then they cost.
http://www.decware.com/newsite/CSP2.htm

This Decware is hard to beat!! It sounds amazing and there are dozens upon dozens of people that will attest to it as well as reviews.

Not to say that what you are building can't compete, hell it might blow it away but its hard to get the sale. Especially these days.

Good thing for you is that at the lowest you are cheaper. These established small businesses don't want to (can't afford to) sell something too cheap - you can. For $250 built and shipped you may sell a few if you can get some positive feedback from users.

Good Luck! Good to see stuff like this.

BillB · « **Reply #5 on:** 12 Feb 2009, 02:06 am »

Yeah the Decware is definitely the closest, but with needing a chassis and the labor involved with that plus needing selection switching and additional RCAs it is probably closer to $350 or more when all is said and done.

Thanks for the feedback, I have a friend who is considering ordering a Decware and I would definitely love to hear it.

I would really prefer to sell these as kits because even at $250 it really is not worth it for me, I think I spent about 15hrs assembling the first one and for $60 or so I might as well be a 3rd world assembly line person. It really is not about the money with me...it is something I enjoy doing and if someone else can enjoy the outcome (and not clutter my house up with more gear) the better.

MaxCast · « **Reply #6 on:** 12 Feb 2009, 02:17 am »

I'd be interested. If it were a kit I'd need pretty good instructions. Any idea how it compares to a Foreplay? I built one of those and probably should dust it off and give it a run.

Another idea is to send it to an audio group.
They could give it a test run and even try it in their own systems for few weeks.

BillB · « **Reply #7 on:** 12 Feb 2009, 02:36 am »

Good thinking.

I have heard a lot of good things about the bottlehead. I would *hope* that the Bottlehead would kill it really, unless the components were upgraded beyond the base level (though I am working on a low price cap that can compete for little cashola). (Considering you could get 2 for 1).

I am trying to work out what is really needed to jack up the performance level and have toyed with "exotic" power supply ideas but I really don't think they will add anything but colorful tubes.

I think a nice CLC with high quality caps and diodes will do the trick and not add much to cost, if anything besides the inductor's price.

We can do some cool stuff too, optional caps, cap selector switches, anything really.

Again, I don't think this is a main system for audiophiles but makes an excellent office, bedroom, aux. system. It is also a great gateway into tubes for those who don't consider themselves audiophiles. Couple this with a cheap USB DAC and a T-amp and it would blow away anyone who ever used PC speakers or receivers for audio.

This is not to say it is bad either...if it was I wouldn't try to sell it and it wouldn't be connected in my system sitting on top of my aikido.

It just has its place and I am too honest a person to try and say otherwise.

django11 · « **Reply #8 on:** 12 Feb 2009, 11:25 am »

First, let me recommend Bill. He made me a great amp. Bill is not into hyperbole. If he says it, it is true. And he doesn't seem to be out to make any money (

). Well, if he is he didn't do to well with me.

I'm having tube lust. In Canadian funds it's going to be more like $350 to my door, so I'm thinking about it. It's tax season around here...

I think if you want to move this thing it's got to be prettier. Tube stuff has that cool look. Definitely go black, lose the blue caps ( I don't know how) and add a single piece of wood across the front ( just screwed on from the inside).

BillB · « **Reply #9 on:** 12 Feb 2009, 01:05 pm »

The "next generation" will use power caps that are much shorter in height and will fit inside the chassis.

FredT300B · « **Reply #10 on:** 12 Feb 2009, 01:10 pm »

Bill, I believe your idea for offering a very affordable tube preamp is great, but at the $250 price you're suggesting for a completed product it's just not a sustainable business idea. At $250 you just don't have enough profit to offer a completed product, and you would soon find it just isn't worth all the work plus the headaches you would have to deal with. A kit product, however, would closely parallel Bottlehed Corp's introduction of their original Foreplay, which initially sold for $99. Adjusted for inflation, your price is probably comparable, and it positions you as the cost leader among the other kit sellers like Bottlehead and Decware.

I would buy one if you could offer the preamp as a kit, priced no higher than $250. I'm sure others would too, not as the final preamp they will own, but as a fun project that enables them to try tubes in their system without breaking the bank. To make it a sustainable business you would also have to build brand recognition and loyalty, which would require a dedicated builder/owner forum.

cujobob · « **Reply #11 on:** 12 Feb 2009, 06:36 pm »

Lloyd Peppard at Mapletree Audio started up in similar fashion but people found out once you added in better parts to his original design, it was taken to a new level. Perhaps build one out with your Level 3 upgrades and compare?

BillB · « **Reply #12 on:** 12 Feb 2009, 11:16 pm »

I have no doubt that better components will make a better product, but it is kind of a "what's the point?" kind of operation then. With all the competition at that price it just makes it just another face in the crowd...and a kind of ugly one at that.

A good thought might be to offer the parts as a kit upgrade so once you finish the stage 1 you can switch to greener pastures with little trouble.

As far as being sustainable and a business...ehhh, not really what I am after. I am thinking about the Pass idea where I build a few and then put out the entire build plan and schematics and let people 100% DIY it...I will even release the build sheet which has part #s from the suppliers so you can just copy paste and buy.

I really like building stuff and enjoy the results but do not need a house full of this stuff. So, the plan is maybe 10 of these guys and then its all yours! Hopefully by then there will be another cool project to build.

bunnyma357 · « **Reply #13 on:** 12 Feb 2009, 11:34 pm »

Quote from: BillB on 12 Feb 2009, 11:16 pm

I have no doubt that better components will make a better product, but it is kind of a "what's the point?" kind of operation then. With all the competition at that price it just makes it just another face in the crowd...and a kind of ugly one at that.

A good thought might be to offer the parts as a kit upgrade so once you finish the stage 1 you can switch to greener pastures with little trouble.

I think this makes sense, get people hooked on the low-cost tubes, and then reel them in with upgraded parts. I know that's what happened to me - get a $400 integrated, then buy $600 in various tubes looking for the perfect combo.

I also think a Kit is the way to go, since appearance wise, although it looks nice, it still has that DIY flavor. And building it would be part of the appeal. With the economy the way it is this is probably a good time to just keep it to the hobby/testing the waters stage - but, in the future I'd definitely be game to try something of yours, and I also really like the appeal of lesser known tubes were NOS stuff is still a bargain.

I think you've built up a fair bit of credibility and respect on the various forums, and I know I'm all about value over ultimate performance, so this type of project really appeals to me. I think you said 60% of the performance for 30% of the cost - that's an equation that works for me and my budget.

Jim C

BillB · « **Reply #14 on:** 13 Feb 2009, 02:24 am »

My wife picked up the 50 Russian NOS 6j6 equivalents today at the post office.

Hopefully they will sound as good as the Westinghouse Germanys I have in now...which have a possibility of being Russian anyways.

acresm22 · « **Reply #15 on:** 13 Feb 2009, 03:27 am »

As someone who doesn't wield a soldering iron with ease, let me say that a simple, good sounding, well-designed tube pre for $250 would be a very, very attractive option...as long as it's not a noisy bugger.
My answer is that interest would be high.

BillB · « **Reply #16 on:** 13 Feb 2009, 04:04 am »

I will admit that it has a tiny bit of hum right now but I think the switch to an aluminum chassis and better isolation of the transformer will take care of it.

I haven't had the time to really experiment. Its no worse than my 90s VTL though.

Rest assured I won't sell 'em that way!

BillB · « **Reply #17 on:** 13 Feb 2009, 11:54 pm »

I just got home to a nice package from Mother Russia.

They all appear to be from the same batch 1-62.

Also received 10 sockets and 20 pairs of RCA.

BillB · « **Reply #18 on:** 14 Feb 2009, 03:35 am »

Preamp with birds eye maple sides: (Ok, side...one is done)

Close-up:

And yes, the lighter color up top is natural.

BillB · « **Reply #19 on:** 15 Feb 2009, 04:31 am »

Some updates:

1) The power supply is going to be revised to a C-RC-RC design. The ripple will be nearly non-existent at an added cost of around $6-7...well worth it IMO.

2) I ordered some Panasonic film caps to try out and a couple little demons as well.

3) These Russian tubes are absolute gems. I was going to offer American tubes as an upgrade and a slightly higher cost but these are so much better it kind of defeats the purpose!! Of course they are a decade older than the American brands I have so maybe that is the key (don't make em like they used to!!)

In the coming weeks I will be building a Rev-2 model which will serve as the construction standard and user manual mule.

Stay tuned!!!