Considering Bottlehead's tubed Foreplay preamp

I currently have a vintage (solid-state) Marantz 2230 as the centerpiece of my system, with Axiom M3Ti bookshelf speakers. I use a Rega Planar 3 turntable (with Dynavector 10x4 cart) through a Monolithic PS-1 phono preamp (also solid-state).

Would I really get any of the tubey benefits of something like the Bottlehead Foreplay DIY kit, even running a solid-state phono pre into it and then going into a solid-state amp (I'd be using the Marantz as an amp)? The Marantz already sounds really good to my ears, but I'm desperately longing to take a first step into tubeland.

I own a soldering iron and have used it successfully to change an internal fuse in my Marantz. I gather this is all the "skill" I'd need to build the Foreplay. True?

 

Yup. The Foreplay is really a simple, easy-to-build unit. As far as tooby pull, it does very well with the right tubes (not the ones included).

The real facts though, it's built for 3 inputs, but with modification room for 6. It does take about an afternoon to build, and the kit takes quite a while to get to you. Doc usually takes 6-12 weeks after payment is recieved.

The pre really pulls some power/leverage, as 1/8 of a crank will be loud enough for just about anyone. Mods are available, but to be honest, I don't need em. It's very clean-sounding and quite simple.

I'm seriously looking at the Paramours sometime soon. Much later!

The percentage of where more tube power gets into the signal is in the final amplification stage. From listening to different combinations, if you want more tuby goodness, the Foreplay is a start, but going tuby at the amplification stage is almost necessary if you want something that shows you a real difference.

 

Thanks Sckott. Maybe I'd be better off saving my $$ for a while and hunting down a Fisher 500-C in good shape, or something ...

 

I don't think I'd be qualified to tell you how a Foreplay would effect the sound of your system with the components you have, but I can give you a few comments about the construction.

I bought "the whole deal" which included the sweet whispers stepped attenuator volume control (which I have yet to install) and the constant current sources (which made a great preamp even better IMHO). I have to say that even tho the construction was not that difficult (at least to me) it was just a little more difficult than the Paramour amps because it seemed like I had to hold the soldering iron in a few uncomfortable positions. Like Sckott says, some tube rolling will be required (but to me thats half the fun). Sckott's also right about the stock volume control being a little sensitive but the sweet whispers would take care of that.


I found it difficult to take the enamel off Doc Bottleheads magnet wire even with so I used standard hookup wire instead. The proper tool for that would probably be a "solder pot" which can be bought at MCM Electronics for about $70. Thats the only exotic tool I can think of that you might need and if you don't use the magnet wire you won't even need that.

For future projects I intend to use teflon coated wire from triode electronics which costs $1.99 for 10 feet. Still collecting parts for a complete homebrew push-pull 2A3. Of course, I've been saying that for a few months.


Gary, do you know if the Foreplay you heard had the constant current source installed? I think it improved the soundstage and increased the speed to the bass greatly.

 

Hi Jeff,

I'm a FP owner and I've very happy with it. With that said, you have to remember that there's a lot you can do with the basic kit that will drastically improve the sound. It's a matter of how much you want to spend and how much you think the basic design is worth investing in. The basic FP kit is a very different animal from one with a bunch of upgrades. The nice thing is, you can control what/how much you put into it.

I had mine built by a good friend who is also an electical engineer. I made the decision after listening (in my system) to the one he built for himself. It was very heavily modified. Not just the Bottlehead upgrades. He put in Hovland caps, Vampire's, etc. Probably most important was switching the standard volume pots for custom 24 step attenuators using Caddock resistors. These changes aren't trivial, but if you're good with a soldering iron... It also kicks the price up quite a bit, but look around to see what you'd have to pay to get this kind of thing in a "store bought" pre.

I also did quite a bit of tube rolling once I had it in my system. The stock tubes were OK. RCA cleartops were better and aren't too hard to find or very expensive. If you can find some Tele 12AU7's, they're better still. BUT, if you can get your hands on a pair of Amperex 7316 PQ's, it will bring the FP to a whole 'nother level.

My friend wrote up a comparison we did with an AES AE-3 pre if you're at all interested.

http://www.audioasylum.com/forums/bottlehead/messages/11509.html

The system has changed since the write-up. VTL ST-85 amp and Theta transport and MSB DAC on either side of the FP.

As with most things in audio equipment, the best bet is to see if you can find someone with a FP and see how it sounds in YOUR system. My main point here is that when one person says he/she heard a FP it may be a very different preamp from what someone else describes.

Have fun.

Mike

 

Hi Mike,

Thanks for all the info. I'll definitely check out your write-up.

I actually enjoy DIY-ing and, if I were to go for the FP, would certainly want to try at least a few mods once I'd had it for a while. It does seem like a relatively inexpensive way to inch into the tube and DIY worlds, and broaden my listening experience at the same time.

I'll mull it all over for a while ... Thanks to everyone who responded to this.

-- Jeff

 

I've thought about playing around with some DIY preamp action with a 12AX7 to rotate in some telefunkens. Schematics are easy to find on the net.

The Push-Pull 2A3 schematic I have uses 6SN7's in the voltage amp (first stage) and the same tube in the phase splitter. But I also have a schematic of a EICO HF-87 which uses the same tube in the phase splitter but uses 12AX7's in the voltage amp. I'm trying to find a way to experience some of the telefunken 12AX7 magic so I don't know which I'm going to go.