Carver Crimson 275 Review (Tube Amp)

[mhardy6647]

OK...obviously, this amp needs a grounding box: https://www.audiosciencereview.com/...s/how-does-an-audio-grounding-box-work.37758/

 

[Holmz]

Does anyone know what the power supply capacity in Joules?

 

[fpitas]

It's odd that your unit has such small wires (and other issues), here is what mine looks like inside....

At the end of the day, the output impedance of a tube amp is relatively high. The thinner wires probably make no significant difference.

 

[vkhong]

Re-marketed with a more realistic power rating?

Black Magic 25

 

[atmasphere]

I wonder if the grounding issue is addressed?

 

[teched58]

Re-marketed with a more realistic power rating?

View attachment 233427
Black Magic 25

But not so much with a more realistic price. The Carver Crimsonfraud 275 was/is priced at $2750. The Black Magic 25 goes for $1995.

The Black Magic 25 has different tubes that the Crimson, so it's not a rebrand. Though I'm sure it has similar teeny tiny output transformers inside those cans. (EDIT: The smaller OTs, which gave away the lies about the 275 spec'd power, are appropriate for the Black Magic 25.)

 

[Xulonn]

The Black Magic 25 has different tubes that the Crimson, so it's not a rebrand. Though I'm sure it has similar teeny tiny output transformers inside those cans. (EDIT: The smaller OTs, which gave away the lies about the 275 spec'd power, are appropriate for the Black Magic 25.)

The Carver Crimson 275 - which has been deleted from the Carver website - weighed 20 lbs. The Black Magic 25 weighs 44 lbs., which suggests proper, much larger output transformers, appropriate for an EL34 PP amplifier. So no - the tiny transformers in the Crimson 275 are still not suitable for an EL34 PP amplifier, much less a KT120 PP amplifier.

Edit: A proper EL34 stereo amplifier - like mine - weighs about 30-25 lbs. As AudiOhm says, the specs at the Caver website appear to be scrambled. This is obviously a company that doesn't care about getting the details right!

 

[AudiOhm]

Looks like they have the specs for the 350 and 25 duplicated/mixed up...

350 (mono amp)
Dimensions (H x W x D) 7.2” (183mm) X 12” (305mm) x 14” (355,6mm) x 2
Weight: 44lbs (19.95 kg) per chassis x 2
https://www.bobcarvercorp.com/crimson-raven-features-specs

25 (stereo amp)
Dimensions (H x W x D) 7.2” (183mm) X 12” (305mm) x 14” (355,6mm) x 2
Weight: 44 lbs (19.95 kg) per chassis x 2
https://www.bobcarvercorp.com/black-magic-features-specs

Why 2 for the 25?

Ohms

 

[mhardy6647]

Well, I was thinking maybe things were better in Carverland -- but, maybe, not so much.
I will confess to Schadenfreude. Sorry, Carver fans.

 

[pseudoid]

Well, I was thinking maybe things were better in Carverland -- but, maybe, not so much.
I will confess to Schadenfreude. Sorry, Carver fans.

I am assuming that the Carverland (you refer to) was originally USA.
Do you possibly think that those habitants really know the difference between Schadenfreude and shut the front door???

 

[mhardy6647]

I am assuming that the Carverland (you refer to) was originally USA.
Do you possibly think that those habitants really know the difference between Schadenfreude and shut the front door???

Oh, I dunno... but I am honest enough to admit to deriving somewhat perverse enjoyment from watching certain train wrecks occur.

 

[fpitas]

Well, I was thinking maybe things were better in Carverland -- but, maybe, not so much.
I will confess to Schadenfreude. Sorry, Carver fans.

I expected better, too. I almost hope they goofed it up on purpose to get a warm, fuzzy sound. Better that than incompetence.

 

[solderdude]

Looks like they have the specs for the 350 and 25 duplicated/mixed up...

350 (mono amp)
Dimensions (H x W x D) 7.2” (183mm) X 12” (305mm) x 14” (355,6mm) x 2
Weight: 44lbs (19.95 kg) per chassis x 2
https://www.bobcarvercorp.com/crimson-raven-features-specs

25 (stereo amp)
Dimensions (H x W x D) 7.2” (183mm) X 12” (305mm) x 14” (355,6mm) x 2
Weight: 44 lbs (19.95 kg) per chassis x 2
https://www.bobcarvercorp.com/black-magic-features-specs

Why 2 for the 25?

Ohms

specs for the BM25:

SPECS (my emphasis)

Gain: 29 dB
Power: More than 24 Watts Per Channel, both channels driven at eight ohms with no more than 1% Total Harmonic Distortion. Distortion decreases at lower levels
4Ω Power 25 watts
8Ω Power 25 watts
16Ω Power 25 watts
Noise: Better than 100 dB below 25 watts, A-weighted
Frequency Response: +0, –2 dB from 20 Hz to 20 kHz
Distortion Less than 1%
Source Impedance 1.7 ohms
Input Impedance 100 kΩ
Vacuum Tubes: EL-34 (optional 6550, KT88, KT120) 12AX7, 12AT7
AC Power:
120 Volts, 60 Hz (US)
240 Volts, 50 Hz (EU
Weight 19 lbs / 8.61 kg
Color: Satin Textured Black, Chrome, Natural Aluminum
Country of Origin: USA

 

[fpitas]

specs for the BM25:

SPECS (my emphasis)

Gain: 29 dB
Power: More than 24 Watts Per Channel, both channels driven at eight ohms with no more than 1% Total Harmonic Distortion. Distortion decreases at lower levels
4Ω Power 25 watts
8Ω Power 25 watts
16Ω Power 25 watts
Noise: Better than 100 dB below 25 watts, A-weighted
Frequency Response: +0, –2 dB from 20 Hz to 20 kHz
Distortion Less than 1%
Source Impedance 1.7 ohms
Input Impedance 100 kΩ
Vacuum Tubes: EL-34 (optional 6550, KT88, KT120) 12AX7, 12AT7
AC Power:
120 Volts, 60 Hz (US)
240 Volts, 50 Hz (EU
Weight 19 lbs / 8.61 kg
Color: Satin Textured Black, Chrome, Natural Aluminum
Country of Origin: USA

I wonder, is that 1.7 ohms Source Impedance the output impedance to the speaker?

 

[SIY]

I wonder, is that 1.7 ohms Source Impedance the output impedance to the speaker?

Almost certainly.

 

[fpitas]

Almost certainly.

Yikes

 

[mhardy6647]

I wonder, is that 1.7 ohms Source Impedance the output impedance to the speaker?

I assume that's the amp's output impedance. If so, then, heck, that's lower (EDIT) higher than that of my zero NFB single-ended 2A3 amp (with output impedance of a hair less than an ohm)!
That would actually be a pretty remarkable engineering achievement* on the part of Dr. Carver!

__________________
* engineering achievement, of course, being a vector quantity. I.e., the Gothic Cathedral at Beauvais (which collapsed several times during construction and ended up being more or less an outrageously glorified chapel, see Hartt's History of Art, vol. 1) and the "Galloping Gertie" bridge over the Tacoma Narrows were remarkable engineering achievements (just not in a good way).

 

[fpitas]

I assume that's the amp's output impedance. If so, then, heck, that's lower (EDIT) higher than that of my zero NFB single-ended 2A3 amp (with output impedance of a hair less than an ohm)!
That would actually be a pretty remarkable engineering achievement* on the part of Dr. Carver!

__________________
* engineering achievement, of course, being a vector quantity. I.e., the Gothic Cathedral at Beauvais (which collapsed several times during construction and ended up being more or less an outrageously glorified chapel, see Hartt's History of Art, vol. 1) and the "Galloping Gertie" bridge over the Tacoma Narrows were remarkable engineering achievements (just not in a good way).

Your 2A3 anode resistance is probably pretty small compared to an EL34. Maybe if you opt for say, the KT88 output tubes the impedance is a bit lower. Maybe...

 

[mhardy6647]

Your 2A3 anode resistance is probably pretty small compared to an EL34. Maybe if you opt for say, the KT88 output tubes the impedance is a bit lower. Maybe...

Yeah, but I don't want no steenkin' tetrodes, kinkless or otherwise. (Power) triodes FTW!

 

[fpitas]

Yeah, but I don't want no steenkin' tetrodes, kinkless or otherwise. (Power) triodes FTW!

If I just had to use tubes, push-pull triodes would be it. Luckily though they made those scratchy old silicon carbide JFETs.