Hand built mono amplifiers

[christoffeldg]

Hey all,

I'm just come across some hand built mono amplifiers of 580W @ 8Ohm for a good price. Are there many things that can go wrong when buying them? What exactly should I look out for?

Here's the link
https://www.hifi.nl/tweedehands/10021073/2x-Monoblok-custom,-referentie-D-klasse.html

For anyone who wonders, my speakers are the B&W 802 D3. These are sensitive, but I feel I'm missing the lower end. I already upgrade from 85W to 200W and this gave a massive improvement. I'm wondering what adding even more power could accomplish.

If you guys want me to provide a translation of the details, no problem.

 

[MrBoat]

I don't know what size room you have, but those speakers should not need anymore headroom than what you already have. The lower end problem could be a room problem. You would likely be better served handing your lower frequencies off to a couple subwoofers. Just because those speakers possess low end capability, does not mean it will be effective as a 3 way in your living space.

Perhaps describe what space these speakers are in, what you are listening to, and other, more experienced folks here would be able to give you ideas. At the point you are at now, louder to get more low end is not a cure.

 

[christoffeldg]

My problem is the extension. These are speakers that should be capable of going truly full range and diving below 20hz. But they're not getting there. I actually have a subwoofer and it is here that I notice the missing depth. But I want the speakers to go full range without the subwoofer.

 

[everettT]

My problem is the extension. These are speakers that should be capable of going truly full range and diving below 20hz. But they're not getting there. I actually have a subwoofer and it is here that I notice the missing depth. But I want the speakers to go full range without the subwoofer.

Have you taken measurements of the speakers in room? What speakers are they?
If you have access to crown amplification I'd look at this

http://www.crownaudio.com/en/products/xli2500

 

[PENG]

My problem is the extension. These are speakers that should be capable of going truly full range and diving below 20hz. But they're not getting there. I actually have a subwoofer and it is here that I notice the missing depth. But I want the speakers to go full range without the subwoofer.

It has probably more to do with your room (what are the dimensions, L,W,H?). Most high quality amplifiers should measure flat between 20-20,000 Hz at less than 0.05% THD+N. For more power, I wouldn't go with those hand make class D amps and go with the try and true well known amps that have good specs verified by available 3rd party lab measurements.

If you don't mind paying more, you can choose one that is rated 300-500WPC from Bryston, Classe, McIntosh, Passlab, Parasound Halo JC mono blocks, Hegel H30 etc., or for a little less, something like the ATI6002 will be more than good enough for the 802 D3. If you don't mind spending less than the Crownaudio pro amps suggested should be fine too.

By the way, looking at the frequency response of the 802 D3 in the anechoic chamber, I would not consider them full range. For them to be full range, it will again, depend on your room.

 

[mtrycrafts]

My problem is the extension. These are speakers that should be capable of going truly full range and diving below 20hz. But they're not getting there. I actually have a subwoofer and it is here that I notice the missing depth. But I want the speakers to go full range without the subwoofer.

Perhaps they should be but cannot at the level you are looking for.
Then, the source comes into the discussion. What was recorded and at what levels?
Don't expect sub performance from a 3/4 way floorstanding speaker.
How about a good powered sub?

 

[TLS Guy]

My problem is the extension. These are speakers that should be capable of going truly full range and diving below 20hz. But they're not getting there. I actually have a subwoofer and it is here that I notice the missing depth. But I want the speakers to go full range without the subwoofer.

I think B & W's spec of this speaker is optimistic. Lets be honest exaggerated. They claim an F3 of 17 Hz, with two 8" woofers, with the sensitivity being in the 90 to 91 db range.

Stereophile measurements show the f3 at 40 Hz which is what I would expect.

A speaker can not play below the free air resonance of the drivers no matter how many you use. An 8" driver would have to have a very heavy cone and a low magnetic flux density in the VC gap to get and free air resonance in the 20 Hz region and the sensitivity would not be in the 20 Hz range.

I do not believe these speakers are truly full range. No amount of amplifier power will make them full range.

I have had a chance to measure the 800 D3 which uses two 10" woofers. It manages an F3 of around 23 Hz, and so is full range and sounds it.

Truly full range speakers are uncommon.

You need a sub or you need to trade your 802 D3s for 800 D3s

 

[christoffeldg]

That's actually not what I'm hearing. I haven't measured it, but anything above 30hz sounds on the same level. Below 30 it gets to 25 before it really dips, rumbling at 20 is still there. I've just tested the tones individually on YouTube, again no measurements.

My sub is a pretty light 10inch sealed box that goes to the same frequencies at 27hz. But the difference is huge. And the speakers are able to really sing with the sub, they felt restrained without the sub.

I need the proper equipment to do a measurement... . Keep meaning to.

 

[PENG]

That's actually not what I'm hearing. I haven't measured it, but anything above 30hz sounds on the same level. Below 30 it gets to 25 before it really dips, rumbling at 20 is still there. I've just tested the tones individually on YouTube, again no measurements.

My sub is a pretty light 10inch sealed box that goes to the same frequencies at 27hz. But the difference is huge. And the speakers are able to really sing with the sub, they felt restrained without the sub.

I need the proper equipment to do a measurement... . Keep meaning to.

As I mentioned before, that speaker is not considered full range without the help of the room. If the room and placement are helping, yes it can come close. TLSGuy explained that very well, the 800 D3 can be considered full range, not the 802s. I would say the 800D, D2 are pretty much full range too.

 

[christoffeldg]

As I mentioned before, that speaker is not considered full range without the help of the room. If the room and placement are helping, yes it can come close. TLSGuy explained that very well, the 800 D3 can be considered full range, not the 802s. I would say the 800D, D2 are pretty much full range too.

I understand, but as I said, it is able to reach at least 25hz smoothly in my room. So even if it isn't able to reach full range. The performance of the speakers should be at least comparable to what the sub is capable of doing up to 27hz.

 

[MrBoat]

I understand, but as I said, it is able to reach at least 25hz smoothly in my room. So even if it isn't able to reach full range. The performance of the speakers should be at least comparable to what the sub is capable of doing up to 27hz.

No, the speakers are likely rolling off rather notably to that lower point. They're not solid at that range. A lot of that low range is cabinet tricks to begin with. I like bass and mid bass punch from main speakers as well and full range without subs sometimes. The speakers I have that will do that solidly, have 12-15" woofers that on their own, will achieve it in simple, bass reflex enclosures nearly on displacement alone. They may reach the upper 20's or lower 30's with room gain, but what that really translates to is more solid performance in the 40hz-60hz range.

There's a reason that the majority of the hi-fi world that use those lower frequencies employ large subwoofers.

 

[christoffeldg]

Btw, thanks a lot for the mention of crown audio which seems like a great budget alternative to try out some higher wattage.

 

[christoffeldg]

No, the speakers are likely rolling off rather notably to that lower point. They're not solid at that range. A lot of that low range is cabinet tricks to begin with. I like bass and mid bass punch from main speakers as well and full range without subs sometimes. The speakers I have that will do that solidly, have 12-15" woofers that on their own, will achieve it in simple, bass reflex enclosures nearly on displacement alone. They may reach the upper 20's or lower 30's with room gain, but what that really translates to is more solid performance in the 40hz-60hz range.

There's a reason that the majority of the hi-fi world that use those lower frequencies employ large subwoofers.

You know, I'll be getting a microphone because now I'm interested. My speakers are very close to the wall, which I suppose means they're getting room gain in the lower regions. I'm using a DSP to even out the response (room perfect).

 

[mtrycrafts]

Chris, it appears you need to get the most power you can afford. End of story. Good luck.

 

[christoffeldg]

Chris, it appears you need to get the most power you can afford. End of story. Good luck.

Is that sarcasm I'm noticing? Sorry if I appear stubborn, but I'm leaving all options open, also powered subs.

I'm actually using one right now and noticing I'm missing something which is exactly why I'm posting here.

 

[PENG]

Is that sarcasm I'm noticing? Sorry if I appear stubborn, but I'm leaving all options open, also powered subs.

I'm actually using one right now and noticing I'm missing something which is exactly why I'm posting here.

In that case, I think we need more info, such as room dimensions, sitting distance, how loud you listen to, what kind of music, media players, preamp, and power amp, subwoofers etc.

 

[Pogre]

I don't know what size room you have, but those speakers should not need anymore headroom than what you already have. The lower end problem could be a room problem. You would likely be better served handing your lower frequencies off to a couple subwoofers. Just because those speakers possess low end capability, does not mean it will be effective as a 3 way in your living space.

Perhaps describe what space these speakers are in, what you are listening to, and other, more experienced folks here would be able to give you ideas. At the point you are at now, louder to get more low end is not a cure.

My towers just don't cut it without my subs. Though I never tried the mini with them.

 

[Pogre]

My problem is the extension. These are speakers that should be capable of going truly full range and diving below 20hz. But they're not getting there. I actually have a subwoofer and it is here that I notice the missing depth. But I want the speakers to go full range without the subwoofer.

Good luck with that. No amount of power is going to change it. Your towers just don't have the extension for it. Adding more power will do nothing. I have a pair of towers and they dig really deep too. They just don't sound as good without a sub. There are so many factors, with placement and room modes being at the top of the list. Sometimes the best spot for your towers isn't such a good spot for frequencies below 200hz or so. this is why folks get subwoofers.

 

[William Lemmerhirt]

I understand, but as I said, it is able to reach at least 25hz smoothly in my room. So even if it isn't able to reach full range. The performance of the speakers should be at least comparable to what the sub is capable of doing up to 27hz.

But how do you know what's reaching where and at what level? You might hear rumbling at 25 but at what spl. Are you at least using an spl meter to know for sure? I'm not being antagonist, just wondering. Even against the wall, room gain is not such a simple thing to count on. Placement is the second most important thing next to the room.