Amplifier for Von Schweikert VR-4 speakers

[jbchang]

Hi all—

I am very new to the world of audio, and I am looking for a budget amplifier recommendation. My family bought a pair of Von Schweikert VR-4 speakers many years ago, and I have been diligently moving them with me for also many years now. I am not sure exactly which generation the speakers are—my best guess is generation 1 (they look like the ones at this link). Recently, I bought a Fosi Audio BT20A to power a smaller pair of bookshelf speakers, and a couple of days ago, I tried powering the VR-4s for the first time with it. I was really surprised at how good they sounded. I was also surprised that the BT20A was able to power the speakers at all—I remember amplifiers being gigantic things, so I guess these newer class D amps are really powerful for their size.

My question: is my BT20A (nb: not BT20A Pro) powerful enough to power the VR-4s? If it is not powerful enough, which amp would be more appropriate? I don't need the best sound quality—I just don't want to damage the speakers (I googled and found that an underpowered amp can lead to clipping and therefore damage to the speakers) and be able to use them. Some sort of wireless connectivity would be nice too. Ideally the amp would cost less than $200, but I'm willing to go up to $500 if I have to. That seems to be on the low end for what amplifiers cost... any used options worth looking into?

I am including the specifications of the speakers below. I'm not sure exactly which type of VR-4 I have, so I'm including specs for all the VR-4 manuals I could find online below.

Best,
Jeremy



Specs for the VR-4JR:

Specs for the VR-4SR:

Specs for the VR-4 Gen III HSE Hovland Special Edition Series (full document here):

 

[NTK]

Welcome to ASR!

Your Fosi BT20A is based on the TI's [edit] TPA31126 amplifier chip. With a 24 VDC power supply it should be able to output 30 W into 8 ohms and 60 W into 4 ohms, which is probably sufficient if you don't listen to high volume or in a big room.

The next step up would be a Fosi V3 (link to review below, USD$110 with the 48 VDC power supply). The max power output with a 48 VDC 5 amp power supply increases to ~100 W @ 8 ohms and 140 W @ 4 ohms.

Fosi Audio V3 Amplifier Review

This is a review and detailed measurements of the Fosi Audio V3 stereo amplifier. It was sent to me by the company and costs US $89.99 with stock 32 volt supply. Price goes up to $109.99 with the 48 volt supply. There is a $10 discount coupon right now. Despite its budget price, the V3...

www.audiosciencereview.com

A further step up would be a Hypex NC502MP based amp (e.g. from Buckeye Amps, USD$750) would give you ~200 W into 8 ohms and 400 W into 4 ohms, which would be more than enough for all intents and purposes driving your Von Schweikerts.

 

[Chrispy]

The fear of a lower power amp damaging your speakers is largely a non-issue. Unless you're driving your small amp well beyond its capabilities deliberately....but judicious use of the volume control should alleviate that concern. Mostly about how loud you want at what distance from your speakers. Maybe play around with this a bit http://www.hometheaterengineering.com/splcalculator.html

 

[Deleted member 48726]

If you want to be sure you aren't clipping your amplifier needs to be 100x as powerful as your average listening power. This is described as headroom and 20 dB is often the safe bet.

So it depends on what distance you are listening to your speakers from and also what kinds of music you listen to and of course what your average listening volume is.

 

[jbchang]

Thank you all—this is very helpful! Seems like the BT20A is fine for my purposes—it's a pretty small room.

I am realizing I was confused in particular by the fact that there is a subwoofer/midrange/tweeter all being powered by the same channel—reading your responses, I am thinking that this doesn't really matter, or at leas that the power ratings provided by Von Schweikert take this into account.

Best,
Jeremy

 

[kemmler3D]

Thank you all—this is very helpful! Seems like the BT20A is fine for my purposes—it's a pretty small room.

I am realizing I was confused in particular by the fact that there is a subwoofer/midrange/tweeter all being powered by the same channel—reading your responses, I am thinking that this doesn't really matter, or at leas that the power ratings provided by Von Schweikert take this into account.

Best,
Jeremy

Correct, the single input on the back of the speaker goes into what's known as a crossover, which is a set of analog filters that splits the audio into high, mid, and low-frequency bands that are appropriate for each driver.

Crossover design has a big impact on the sound and is the subject of a great deal of discussion with regard to speaker performance.

Occasionally you'll find a passive speaker (i.e. requires external amp) that gives you the option of feeding multiple amplifiers into the back, which is known as bi- or tri- (or quad, rarely) amping.

More commonly, you'll see speakers that support what's known as "bi-wiring" where you feed the full range signal, from the same amp, to separate inputs. Since you're not giving each section a separate amp, it's seen as less useful.

Active speakers have the amps built in, and modern ones often have digital crossovers, which are not subject to the same trade-offs as analog/electronic crossovers. Filters of arbitrary complexity can be implemented at no additional cost, which gives speaker designers more options on how to squeeze performance out.

Well, this turned into a bit of a novel. Anyway, right, all 3 drivers run on the same amp.