• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Carver Crimson 275 Measurements

SIY

Master Contributor
Technical Expert
Joined
Apr 6, 2018
Messages
7,304
Likes
16,054
Location
Alfred, NY
Don't be put off thinking their website was composed in Crayolawrite 1.0. They take a while too. That's how it is during a pandemic, apparently.
Their downloadable "Specifications" Excel sheet is a revelation.
 

LTig

Major Contributor
Forum Donor
Joined
Feb 27, 2019
Messages
3,893
Likes
6,243
Location
Europe
View attachment 178908
Here's the amp hooked up to a test woofer with the speaker - terminal floating.
View attachment 178907
Here is the amp playing into the same woofer at the same level but with a clip lead connecting speaker - to the shell of an RCA jack.

So there is a difference that's not substantial and very much frequency dependent. While I can measure this here pretty easily, it inspired me to look at some tests into an actual woofer (a little 3" Hivi).

At 1% THD/40Hz, I can get about 600mV (not going to talk about power since the impedance curve is all over the place) with the speaker - floating. If I put a clip lead from speaker - to the shell of an RCA jack, that number goes up to around 720mV.

If I try this again at 1% THD/250Hz, I can get 2.9V with speaker - floating and 3V with the speaker - grounded.

These are different, but I will leave it to others to properly quantify this in ways maybe I shouldn't ;)
Looks like connecting the speaker with the RCA shell decreases output impedance because the output is higher where the speaker impedance is low, probably due to higher negative feedback. I would therefore recommend to use it as such - more power, less FR dependency, less THD.
 

Zackthedog

Member
Joined
Nov 16, 2019
Messages
80
Likes
112
There seems to be some confusion creeping into this discussion. Regardless of subjective listening experiences, the power and output transformers in the units that were examined fall far short of the capability needed to meet this amplifier's specifications. Has that changed?

Jack
There's no confusion. Two owners have reported subjective experiences--and it seems that in both cases the amps fell short in exactly the way the measurements would suggest.
 

Zackthedog

Member
Joined
Nov 16, 2019
Messages
80
Likes
112
You pay for them and they may take a while to deliver. Last time took 4 months. You can get higher quality transformers (IMO) from Heyboer
Don't be put off thinking their website was composed in Crayolawrite 1.0. They take a while too. That's how it is during a pandemic, apparently.

Mercury Magnetics also makes nice stuff. I'd not be surprised to find these three manufacturers make 90% of the musical instrument output transformers made in the US.

They do a lot of 'hifi' stuff too.

Well, I have Peerless S-265-Q originals and Heyboer copies. The Heyboers are extremely good and come very close to the originals. They make a wonderful "original" American-style Williamson amp. But Heyboer now takes even longer than Edcor, I'm afraid. I've had a pair on order for 6 months now. But at least you don't have to pay up front.
 

ruchwr

New Member
Joined
Jan 14, 2022
Messages
1
Likes
0
The amps shown appear to be the amps from the 2018 Carterfest where people can build their own amps and not the retail factory amps. The Carterfest amps were 20 watt /channel amps did not have a name plate and the pictures I see remind me of the builds I have done in the past. I am the owner of a factory Crimson275 and would bet that if tested properly would show much different numbers.
 

Zackthedog

Member
Joined
Nov 16, 2019
Messages
80
Likes
112
The amps shown appear to be the amps from the 2018 Carterfest where people can build their own amps and not the retail factory amps. The Carterfest amps were 20 watt /channel amps did not have a name plate and the pictures I see remind me of the builds I have done in the past. I am the owner of a factory Crimson275 and would bet that if tested properly would show much different numbers.
There's one on the bench as we speak. The production models have the same 15 watt output transformer, same PCB. Most of us don't expect to see much of a difference, but we could be wrong.
 

jjptkd

Member
Joined
Jan 13, 2022
Messages
5
Likes
7
The amps shown appear to be the amps from the 2018 Carterfest where people can build their own amps and not the retail factory amps. The Carterfest amps were 20 watt /channel amps did not have a name plate and the pictures I see remind me of the builds I have done in the past. I am the owner of a factory Crimson275 and would bet that if tested properly would show much different numbers.
These are quotes posted by Frank the owner of Carver Corp over on the Audiogon forum:

"The amps actually put out 90w or so at 1k into 8ohms, one channel, with .6% distortion."

"They put out clean 90W down to 80Hz, and distort more as it goes down, due to the lack of steel in the output transformers."

 

mhardy6647

Major Contributor
Joined
Dec 12, 2019
Messages
4,323
Likes
8,243
You pay for them and they may take a while to deliver. Last time took 4 months. You can get higher quality transformers (IMO) from Heyboer
Don't be put off thinking their website was composed in Crayolawrite 1.0. They take a while too. That's how it is during a pandemic, apparently.

Mercury Magnetics also makes nice stuff. I'd not be surprised to find these three manufacturers make 90% of the musical instrument output transformers made in the US.

They do a lot of 'hifi' stuff too.
Let me put in another good word for Heyboer. Very good quality transformers at extremely reasonable prices -- but here's the other piece. Heyboer's been around forever. They made, e.g., the original power transformers for EICO's venerable HF-81 stereo integrated amplifier-- and they're still happy to make a replacement PT for an HF-81, including a variant that's uprated a bit to contend with modern line voltages (plus to correct for the rather borderline adequacy of the original PT as spec'd by EICO in the late 1950s). I bought one for my late '50s-vintage HF-81 to have a spare, which should hold it for another six or seven decades after the original PT fails (it's still OK, so far).

I understand they're pretty good to work with for made-to-order transformers, too -- but I haven't had 'em do any custom work for me.
 
  • Like
Reactions: SIY

AudioTodd

Active Member
Joined
Oct 17, 2019
Messages
176
Likes
253
Zack, I would never besmirch John Curl, God knows I bought enough of his equipment. I just think it is funny every reference about the man starts out "the legendary John Curl." He is a much more modest gentleman than that! And I totally agree with honest measurements. If the amp is seriously less powered than advertised I will look for something else. I am not lying though when I tell you these LFT 8b's and this amp keep me up past my bedtime.
If you like it, why look elsewhere??
 

Chazz6

Member
Joined
Mar 4, 2021
Messages
72
Likes
53
These are quotes posted by Frank the owner of Carver Corp over on the Audiogon forum:

"The amps actually put out 90w or so at 1k into 8ohms, one channel, with .6% distortion."
"They put out clean 90W down to 80Hz, and distort more as it goes down, due to the lack of steel in the output transformers."

Right, those words are actually Frank Malice, excuse me, Malitz, offering a quote, he says, "From Edward Suver (our WA tech support, QC and manufacturing supervisor..." The date of the post is Jan. 4, 2022 and it is at
 

LTig

Major Contributor
Forum Donor
Joined
Feb 27, 2019
Messages
3,893
Likes
6,243
Location
Europe
These are quotes posted by Frank the owner of Carver Corp over on the Audiogon forum:

"The amps actually put out 90w or so at 1k into 8ohms, one channel, with .6% distortion."

"They put out clean 90W down to 80Hz, and distort more as it goes down, due to the lack of steel in the output transformers."
Spec is 75Wpc, from 20Hz - 20kHz, THD <= 1%, if I remember correctly. Not much reserve for the rise below 80Hz. We will see ...
 

Chazz6

Member
Joined
Mar 4, 2021
Messages
72
Likes
53
Spec is 75Wpc, from 20Hz - 20kHz, THD <= 1%, if I remember correctly. Not much reserve for the rise below 80Hz. We will see ...
Yup. From dealer Jim Clark Stereo's web page for the Crimson 275:
More than 75 Watts Per Channel, both channels driven at eight ohms, from 20Hz to 20kHz with no more than 1% total harmonic distortion. Distortion decreases at lower levels.
https://jimclarkstereo.com/Bob-Carver-Crimson-275-Stereo-Vacuum-Tube-Amplifier-p115352773
 

Vladimir Filevski

Active Member
Joined
Mar 22, 2020
Messages
227
Likes
296
The amps shown appear to be the amps from the 2018 Carterfest where people can build their own amps and not the retail factory amps. The Carterfest amps were 20 watt /channel amps did not have a name plate and the pictures I see remind me of the builds I have done in the past. I am the owner of a factory Crimson275 and would bet that if tested properly would show much different numbers.
No need for testing - just take off the output transformer cover, photograph the output transformer (with clear view of sticker with the power specification) and post the photograph here, please.
 

Larry B. Larabee

Active Member
Joined
Nov 24, 2021
Messages
183
Likes
90
Its easier to see if you observe a sine wave and push it to clipping. You'll see the sharp edges of a solid state amp make the sine wave look like someone clipped the top off with a pair of scissiors. A tube amp will round those corners- you have to push it pretty hard to get the corners as sharp as a solid state does. View attachment 178883

The image is what I'm talking about. If you just look at the distortion curve you won't see this.
Even if surprising to some claiming to be knowledgeable in all things electronic and never hearing about tube amp soft-clipping no one has actually explained the reasoning for this characteristic in tube amps.
A limited bandwidth would explain the rounded corners at clipping.
I doubt that the supply rails are very stiff, so it could have something to do with load regulation and in that same area the load regulation when referring to the damping factor which in these amps is usually low, much like the user's expectations. (yes, I'm taking a shot at tube guys every chance I get.)

Someone surely knows the reason for it.
 

Rottmannash

Major Contributor
Forum Donor
Joined
Nov 11, 2020
Messages
1,661
Likes
1,264
Location
Nashville
I think the draw of S.S. was its reliability, low heat output, and compact lightweight size; no tubes to fizzle out & need regular replacement and no bad backs caused by heavy transformer-laden chasses. My preference happens to go with home brew tube amps & preamps. They're fun to make, parts are readily accessible, and when you're done, there's the music. I'm a happy camper, and if the equipment breaks down, I can readily get it going again. As for the weight, well, I am a gym user, so it's no big deal.
Can't get to the gym? Just curl. deadlift and overhead press your tube amps.
 
Top Bottom