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Old 25th July 2008, 10:52 PM   #1
agweeks is offline agweeks  United States
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Default Looking for feedback on Bottlehead amps

I just finished law school and finally have the time necessary to build a tube amp—a desire I have had for almost 3 years now. I am tempted to purchase Foreplay III by Bottlehead but am unfamiliar with the DIY community and worry about the fact I haven’t heard the amp and am unable to find any reviews of the bottlehead amps.

I was hoping that someone on the forum either owns or has had a chance to audition the amp would be willing and able to give me some substantive feedback.
Thanks,
Adam
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Old 26th July 2008, 12:35 AM   #2
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Adam,

The Foreplay 3 is a nice enough preamp. What you get is source selection, volume control, and some (perhaps too much) gain. You still need power amplification. The Bottlehead SEX will work using a CDP and speakers, BUT those speakers have to be very efficient.

You really have to think of the amp and speakers as an organic whole. Have you given thought to the sort of speakers you intend to use?
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Old 26th July 2008, 02:55 AM   #3
agweeks is offline agweeks  United States
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I have a pair of klipsch SB2 speakers. The plan was to get a pair of the bottlehead monoblocks-but as I am new to all of this and unableto hear any of these amps, all of this is up in the air. As of now, my system cosists of a JVC amp, the klpsch spaekers and my samsung dvd player for cd's and an old Technics turntable.

Thanks for the response.
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Old 26th July 2008, 02:55 AM   #4
agweeks is offline agweeks  United States
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Thanks Eli,

I have a pair of Klipsch SB2's with an efficiency rating of around 92--I think. These are the speakers I plan to use.

I am currently using a JVC integrated amp that was given to me by a friend. I am so very disappointed with my setup right now; it is driving me crazy. The sound stage is undefined and very flat. I'm chomping at the bit to improve my system but want to get it right and want to have a hand in doing it myself. For these reasons, I want to first learn about DIY amps and speakers and map out a roadmap.

Right now I'm studying for the bar exam (which will take place tue, wed, and thur of next week). After I am done with that, I plan to turn my laser focus on learning about amps and tubes, and speakers and such.

As of right now, in terms of components, all I really have are the Klipsch speakers, an old technics turntable, a samsung dvd player, and an iPod--yes folks, its true, I listen to music on an iPod. The attraction of having all that music right there at my fingertips is just to irresistible.

Is it possible to run a preamp into an amp like the JVC that I have?

Thanks for the response; I appreciate it.

AGW
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Old 26th July 2008, 03:34 AM   #5
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Quote:
Originally posted by agweeks
Right now I'm studying for the bar exam (which will take place tue, wed, and thur of next week).
When I was 4 days from the bar, the last thing I was thinking about was flat soundstage.


Quote:
Originally posted by agweeks
Is it possible to run a preamp into an amp like the JVC that I have?
Yes, but it isn't going to do you much good. Chaining a decent preamp before the bad one is not going to improve anything.

If you are interested in a DIY solution, my advice would be to build a quick Gainclone power amp, then a tube preamp. The Bottlehead is fine, if a little heavy on gain. There are better designs floating around here, most of which will be cheaper though they will require more thought on your part. I'd search for the 12B4 preamp threads. Tube power amps generally require more care and more work, and are probably best not rushed into.

Good luck on the bar. I rather enjoyed it myself.
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Old 26th July 2008, 04:52 PM   #6
zobsky is offline zobsky  India
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92dB efficient multi-way speaker is MARGINALLY sufficient for a 3.5w 2A3 amplifier. Okay for normal level listening, but maybe not as dynamic as needed. Keep in mind that the crossover will rob some power.

I went through a similar exercise a couple of weeks ago listening to a 1.5W SET on various speakers . Only the mid-high efficiency single drivers speaker (fostex 166E) or the high efficiency multi-way (15" co-ax) were worth listening to long term.

I haven't heard BottleHead 2A3 with mid-efficiency speakers, but they aren't too bad with higher efficiency speakers.

If I were you:
1. consider higher efficiency (and larger speakers) and build your 2A3 amplifier
OR
2. Look for a higher power amplifier (maybe 300B, EL34, 6L6 ....). Something about 10 W should work for "normal" sized speakers . Might be worth looking into tubelab products .

(2) might be the more sensible alternative for now unless you are willing to get into speaker building, in which case (1) would be superior.

Pick your poison
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Old 26th July 2008, 07:06 PM   #7
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Quote:
As of now, my system cosists of a JVC amp, the klpsch spaekers and my samsung dvd player for cd's and an old Technics turntable.

Adam,

By some miracle, does the JVC amp have a preamp-out/amp-in feature? Should that be the case, implementing a better sounding system, in stages, becomes easier.

In order to use the TT, a phono preamp is necessary. I assume that the JVC integrated has a phono section. Even if the JVC unit lacks the preamp-out/amp-in feature, you can still use its phono section and source selection capabilities. Whatever source, including phono, you select appears at the recording O/Ps of the tape monitor loop. So, that's where you take the signal from, to drive the tubed stuff you will build.

Where a preamp-out/amp-in feature helps is that the SS line level circuitry can be completely taken out of the signal path. "Dummy" loads are placed in the preamp-out jacks and the amp-in jacks are driven by tubed line level circuitry.

OTOH, should the JVC integrated lack the ability to separate the line and power sections, you will not be able to make use of anything SS, except the phono section.

The rest of the "crew" here and I need to know exactly what is available to work with, in order to make good recommendations. The fact that 15 HONEST WPC should be enough to drive your Klipsch speakers definitely works to your advantage.
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Old 26th July 2008, 07:57 PM   #8
agweeks is offline agweeks  United States
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Hello All. Just came up from taking a long practice exam. Thank you for your responses. They're much appreciated.

In response to Eli's inquiry regarding a pre-amp in or out, I can't find that the JVC has such a feature. It has the normal integrated amp inputs, including: cd, video, tape in and out, phono, VCR, TV. It has a sub out i noticed; but no preamp input output is to be found.

I'm not adverse to scraping the whole amp. I've been investigating zobsky's suggestions and found the TubelabSE to be attractive. It looks as though for a portion of the price of a bottlehead, I can get 15 watts per channel.

I'm a bit unclear on this point: does the type of tube used in the amp adjust the output level to the speakers? I've seen this referred to as tube rolling. I'm imagining a tube cellar next to my wine cellar and me emerging from both with "bottles" in both hands saying "honey" tonight we having an '04 Napa Cab and a NOS RCA.

Are there other folks out there that make and sell pc boards like tubelab? I'm getting the sense that the only real assets I have are my Technics turntable and my speakers. I, therefore, need to examine my options for a pre-amp and an amp in relation to my Klipsch's.

(I'm guessing this will be a life-long passion for tinkering so your suggestion Zobsky that I take up speaker building will come later I'm sure.)

Again, thanks everyone for the input. It's much appreciated.

AGW
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Old 27th July 2008, 03:46 AM   #9
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AGW:

Tube rolling simply refers to swapping out different brands of tubes (NOS tubes (old Mullards, RCA's etc or new Russian, Chinese, etc) to tweak the sound to ones liking. Depending on the amp, the differences are sometimes subtle, sometimes not. Things like high freq extension, soundstage, lush creamy midrange, etc are some of the parameters that you can experiment with.

FWIW, I am also a tube newbie and I'm just finishing my first tube amp build (Gingertube's "baby huey" EL84 12W PP found on this forum) and the amp has exceeded my expectations and changed my opinion on how much power you really need. It has also been an extremely satisfying experience.

You may want to summarize your electronics experience for the folks here, that will help determine where you should jump in as far as kits go, etc. Do you know which end of a soldering iron to hold on to? Multimeter experience?

You can always build an integrated amp kit (has a vol control and possibly a source selector) and later modify it (remove the controls for a pure power amp) when you've built a dedicated preamp, or if you build an integrated with just a vol control you can use Eli's "tape out" suggestion above. That will use your JVC amp as simply a source selector.

Also keep in mind that kits (or scratch built amps) can use printed circuit boards or "point-to-point" wiring which uses no PCBs, just wires sockets and terminal strips. I'm not sure that either style is much easier or harder than the other, just different.

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Old 27th July 2008, 03:33 PM   #10
agweeks is offline agweeks  United States
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Quote:
You may want to summarize your electronics experience for the folks here, that will help determine where you should jump in as far as kits go, etc.
To summarize my electronics bona fides, I do know which is the business-end of a soldering iron and I can read a multi-meter. That being said, this experience was earned years ago while in college. In order to put myself through school, I worked as an electrician's apprentice and then installed phone switches for a year after graduation. So I have a basic understanding of electronics and a GREAT respect for safety.

I would feel comfortable constructing either a circuit board kit or a point-to-point kit but less comfortable sourcing and constructing an amp from a schematic alone.

It also occurs to me that it may be helpful to summarize my listening habits and music tastes. I live in a loft apartment--it's actually a renovated nineteenth century elementary school classroom. The ceiling is about eighteen (18) feet tall. I'm sure that my speakers are not adequate for the room but it is an apartment and I do have concerns about offending my downstairs neighbor. The Klipsch's I run are on stands. The lack of bass in them kind of works to my advantage in that regard.

The listening area is only a portion of the apartment. The seating is about fifteen (15) feet from the speakers. The speakers are about a foot from a wall.

For the most part, I listen to alternative rock music (lots of guitar). I love Tom Waits, Guided by Voices, Spoon. I also listen to artists such as Randy Newman (lots of piano), Nina Simone (intimate female vocals), and Miles Davis (Jazz Jazz Jazz).

It is important to be able to attenuate the volume and select the source. But I embrace the home-brew aesthetic and approach to these amps. The musical listening experience is what is most important to me. I want to feel as though the performers are in the room with me--but hey, who doesn't right?

I need a system that will appease me immediately. I will eventually replace each component over time. For now, however, I want to spend $500 and pull myself out of this black hole I currently find myself in. To that end, any suggestions on amp kits (be they point to point of CB based) that are out there are great. That is what I really need.

Thanks again for all of everyone's kind consideration, I look forward to reading your responses.

AGW
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