BX-500 Review and Write-up

[GearHeadBassMan]

Digital? Does this amp put the signal through some required digital processing?

It's a class D poweramp, which is some mumbo jumbo. it's a digital power supply, in the most lamen's terms.

same as all the other small form factor amps

 

[WoodyG3]

Like you, I'm a BDDI addict. I use one with my Markbass LMII head, and it's good to know it would work well with the Carvin head, too.

Thanks for the review. Please let us know how it works for you in the band setting.

 

[theory028]

That was an informative review. It makes me wish the B1500 was a hybrid amp.

If I were to switch to a micro rig I would probably use a BX500 with two Avatar B210s. The burgundy and gray Fender grill look fantastic; two of them stacked vertically would be something I'd love to try.

I'll have to look into the BDDI. I want a touch of dirt for a few songs that I do and the VT Bass just hasn't been giving me what I want. I'm still experimenting with it so I haven't ruled it out yet. It's a fun pedal to have so I'll be holding onto it but may end up using it for a different goal.

Have fun with your new Carvin!

 

[tonebrulee]

It's a class D poweramp, which is some mumbo jumbo. it's a digital power supply, in the most lamen's terms.

same as all the other small form factor amps

I got curious about class D amps and found this from the Wikipedia article on amplifier classes:

The letter D used to designate this amplifier class is simply the next letter after C, and does not stand for digital. Class D and Class E amplifiers are sometimes mistakenly described as "digital" because the output waveform superficially resembles a pulse-train of digital symbols, but a Class D amplifier merely converts an input waveform into a continuously pulse-width modulated (square wave) analog signal. (A digital waveform would be pulse-code modulated.)

and this...

Class D amplifiers are much more efficient than Class AB power amplifiers. As such, Class D amplifiers do not need large transformers and heavy heatsinks, which means that they are smaller and lighter in weight than an equivalent Class AB amplifier.

So, it sounds like class D provides the advantages that allow these "micro" heads, but requires putting the input signal through a very different process to amplify it. I'm guessing the "sounds digital" issue is around the sound quality in general of a class-D amplified rigs.

 

[KJung]

I got curious about class D amps and found this from the Wikipedia article on amplifier classes:



and this...



So, it sounds like class D provides the advantages that allow these "micro" heads, but requires putting the input signal through a very different process to amplify it. I'm guessing the "sounds digital" issue is around the sound quality in general of a class-D amplified rigs.

It's actually the switching power supplies (SMPS) that allows for the 'micro amps' to be very small. Class D amps help also, but it is the power supply that really cuts the weight.

For example, the Markbass LMII/III are actually class A/B, but with SMPS. Many think this is why they sound so, so good (i.e., sound similar to many traditionally designed heads that are much larger and heavier), since you get what many describe as the 'warmth' of the class A/B power amp, but the weight and size advantage of that little switching power supply. The Markbass F1/F500 have the same preamp (in general.. the features differ) and power supply as the LMII/III/LMTube, but use a class D amp versus the class A/B, allowing them to be a little smaller, and also a bit 'tighter and quicker' in voicing (The F1 and F500 are, by far, my favorite micro amps).

On the other hand, the Epi502 and the iAmp800 have more traditional toroidal power supplies combined with class D amps... hence, they do run very cool, but are much larger and heavier.

In my experience, the class D 'sound issue' is rapidly becoming a thing of the past, in general. The class D TecAmp Micro's are as warm and fat as anything I've ever heard, as is the Epi502.

However, that unique combination of a more traditional class A/B power amp with the very lightweight SMPS is what many feel sets the LMII/III/LMTube apart from the rest of the micro amp field at this point (Edit: The only other amps that I am aware of with this design are the TecAmp Puma350, and the discontinued Genz amp that predated the Shuttle series... I can't remember the name of it. The Puma350 is micro sized, the Genz was not).

 

[Dolflundgren]

Nice man!

 

[tonebrulee]

It's actually the switching power supplies (SMPS) that allows for the 'micro amps' to be very small. Class D amps help also, but it is the power supply that really cuts the weight..

Hey KJung - thanks for the excellent overview.

With guitar amps, the "heavy iron" in the amp are the two transformers - one for the power supply and one for the output signal just before the speaker - and are frequently about the same size. I'm guessing that b/c bass amps are so much larger in terms of overall power (e.g. 100W guitar amp vs. 1000W bass amp), the power transformers are much larger and contribute more to the overall weight?

If so, that would make a lot of sense about the Mark amps - taking the larger weight savings just in the power section but using a traditional amp signal path w/output transformer. They must weigh a little more than the BX500, right? ... maybe an extra 5lbs?

 

[KJung]

Hey KJung - thanks for the excellent overview.

With guitar amps, the "heavy iron" in the amp are the two transformers - one for the power supply and one for the output signal just before the speaker - and are frequently about the same size. I'm guessing that b/c bass amps are so much larger in terms of overall power (e.g. 100W guitar amp vs. 1000W bass amp), the power transformers are much larger and contribute more to the overall weight?

If so, that would make a lot of sense about the Mark amps - taking the larger weight savings just in the power section but using a traditional amp signal path w/output transformer. They must weigh a little more than the BX500, right? ... maybe an extra 5lbs?

+1 that the power supplies on bass amps can get pretty hefty. That's why the SMPS thing is so exciting. In the past, many felt that the SMPS amps could not deliver the ooomph of a more traditional, heavy power supply. Ten years ago, I would have had to agree (for example, my old 1200 watt Walter Woods Ultra, while loud as heck, never really (IMO) produced that sort of 'hit you in the chest' thing that can be so key to a great bass tone). Back then, while I used my Walter for 90% of my gigs, I always kept a bit lead sled around (in my case, an SWR900) for the gigs where I knew that I really needed to slam. Those days are over IMO!

The Epifani 502 and the iAmp800/500 seemed to be kind of 'transitional' designs, using class D power amps to reduce the weight somewhat, but still keeping the heavier toroidal power supplies for the ooomph (both companies now use class D combined with SMPS in their newest high power amps).

Now, a well designed SMPS amp can perform IMO and IME with the best of the more traditionally designed amps with heavier power supplies.

The Markbass LMIII, is, I believe, around 6 pounds or so (so, still stupid light!). The class A/B amps seem to add more size than weight (and I believe require more cooling). That class A/B amp/SMPS design is really pretty cool, in that it allows those who want a touch more of a 'fat, warm, pseudo vintage' type tone (which never seems to be attained by simply cramming a 12ax7 into the design of an otherwise solid state amp) to get there in a micro format.

IMO of course!

 

[tonebrulee]

In the past, many felt that the SMPS amps could not deliver the ooomph of a more traditional, heavy power supply. Ten years ago, I would have had to agree (for example, my old 1200 watt Walter Woods Ultra, while loud as heck, never really (IMO) produced that sort of 'hit you in the chest' thing that can be so key to a great bass tone). Back then, while I used my Walter for 90% of my gigs, I always kept a bit lead sled around (in my case, an SWR900) for the gigs where I knew that I really needed to slam. Those days are over IMO!

That's really interesting how significant the power supply can be in a bass amp. Being outside the signal path I wouldn't have assumed it played a role, but you can see how the ability to deliver a large amount of power very quickly could effect the transitions - which we experience as "dynamics", "oompf", etc. - that are so particularly important for bass.

 

[KJung]

That's really interesting how significant the power supply can be in a bass amp. Being outside the signal path I wouldn't have assumed it played a role, but you can see how the ability to deliver a large amount of power very quickly could effect the transitions - which we experience as "dynamics", "oompf", etc. - that are so particularly important for bass.

+1 I'm surely not an EE, so the technical reasons are over my head. However, these SMPS amps have gotten REALLY good over the last couple of years!

 

[TRob1293]

You may want to read the book that comes with the amp - There seems to be no BX preamp and BDDI 'blend' when connected through the loop. Here is the manual quote:
16. EFFECTS LOOP
The SEND jack is the output of the preamp and is designed to deliver the proper level for the input of an external effects processor. The SEND signal source is after the TONE CONTROLS and COMPRESSOR.
The RETURN jack is designed to receive signals from the output of an external effects processor.
When a signal is plugged into the RETURN, it breaks the connection between the preamp and the internal power amp. The RETURN signal goes through the GRAPHIC EQ (if active) and MASTER controls to the power amp.

The BDDI is a 'tube emulator' so it sounds like an engaged tube, and actaully turns into your PRE-Amp when plugged into the effects loop.

I have the Carvin BR510N and the Sansamp BDDI- I use the BDDI as a 'vintage' emulator through the effects chain connected into the amp input on the front. Whenever I want the older vintage lowend sound, I engage the BDDI. I'm saving for the Sansamp VT Bass to use as my OD 'dirt' pedal.

There is a built-in protection circuit (but no limiter light when you are close to meltdown - amp just shuts off).
14. PROTECT LED
The PROTECT LED indicates one of the protection circuits has activated and no sound will be heard
from the amp. To reset the amp, turn the power off for about 10 seconds, then turn it back ON. If the
PROTECT LED stays lit for more than 5 seconds check your SPEAKER OUTPUT connections, the 2 OHM
switch, or a blocked fan intake.

I love this amp and have found a TON of tonal possibilities.
The Graphic EQ simply ads a tremendous amount of tone you can play with and experiment with. Have fun!

 

[GearHeadBassMan]

You may want to read the book that comes with the amp - There seems to be no BX preamp and BDDI 'blend' when connected through the loop. Here is the manual quote:
16. EFFECTS LOOP
The SEND jack is the output of the preamp and is designed to deliver the proper level for the input of an external effects processor. The SEND signal source is after the TONE CONTROLS and COMPRESSOR.
The RETURN jack is designed to receive signals from the output of an external effects processor.
When a signal is plugged into the RETURN, it breaks the connection between the preamp and the internal power amp. The RETURN signal goes through the GRAPHIC EQ (if active) and MASTER controls to the power amp.

The BDDI is a 'tube emulator' so it sounds like an engaged tube, and actaully turns into your PRE-Amp when plugged into the effects loop.

I have the Carvin BR510N and the Sansamp BDDI- I use the BDDI as a 'vintage' emulator through the effects chain connected into the amp input on the front. Whenever I want the older vintage lowend sound, I engage the BDDI. I'm saving for the Sansamp VT Bass to use as my OD 'dirt' pedal.

There is a built-in protection circuit (but no limiter light when you are close to meltdown - amp just shuts off).
14. PROTECT LED
The PROTECT LED indicates one of the protection circuits has activated and no sound will be heard
from the amp. To reset the amp, turn the power off for about 10 seconds, then turn it back ON. If the
PROTECT LED stays lit for more than 5 seconds check your SPEAKER OUTPUT connections, the 2 OHM
switch, or a blocked fan intake.

I love this amp and have found a TON of tonal possibilities.
The Graphic EQ simply ads a tremendous amount of tone you can play with and experiment with. Have fun!

huh, you're right! maybe I was finally hearing my BDDI now that it's being put at an acceptable output lever.

still, the graphic EQ still being usable is tempting. Will have to mess around with it today!

 

[Lia_G]

(Edit: The only other amps that I am aware of with this design are the TecAmp Puma350, and the discontinued Genz amp that predated the Shuttle series... I can't remember the name of it. The Puma350 is micro sized, the Genz was not).

That would be the NeoPak 3.5. A very nice head that I gigged a lot with blues and southern rock bands.

Cheers,
Liam

 

[Boostedrex]

Very nice review. Thank you for taking the time to be so in depth. I do have to admit that I don't like the large amounts of glue all over the board like that. I prefer a much neater/cleaner board. Yes, I'm anal.

I have a Carvin store about 15 miles from my house and I think it's time I dropped in there for a visit/audition.

 

[tombowlus]

I do have to admit that I don't like the large amounts of glue all over the board like that. I prefer a much neater/cleaner board. Yes, I'm anal.

Isn't that silicon, not glue?

 

[KJung]

Isn't that silicon, not glue?

+1 That's there for a reason.

 

[Boostedrex]

BS. No reason to have it slopped all over the place like that. That's a sign of rushing to get the board finished. Unless there is some difference between building boards for heads vs boards for home and car amps.

 

[vinxbass]

I have a Carvin store about 15 miles from my house and I think it's time I dropped in there for a visit/audition.

Definitely go check out your hometown Carvin store, it's really top notch; Mike the manager and David the sales associate are great to work with.

BTW, great review, though I laughed a little about you reviewing the packaging, I guess that's pretty important too.

 

[Boostedrex]

Will do Vinxbass. Thanks for the heads up on the store too. Carvin seems to make a very solid product from all the reviews I've read.

 

[gregoire1]

Great review! For this price I would expect a 500w amp, micro-head, or tube pre, but NOT ALL THREE!!! Looks like an incredible deal!