Carver Crimson 275 Review (Tube Amp)

[traderitch]

Everyone is entitled to their opinion, but you’re not entitled to keep telling others what they should or shouldn’t post, nor how they should express their own opinion.

I really don't understand the point of your comment.
I merely stated that people that chime in to say the equipment in question is a pos are not really
adding anything of value to those who are here to learn more about its shortfalls.
Personal attacks shouldn't be posted (although I was very direct and honest on an earlier reply.)

 

[john2017]

According to Google they operate from a flower shop

Bob Carver

www.google.co.uk

Actually it is a PO box in the UPS Store.

 

[paulbottlehead]

R53 is not used to set bias. I am asking if the voltage drop measured across R53 is used to set the bias.

With no music signal coming out of the amplifier, there is no voltage developed across R53, so it would be impossible for it to factor into setting the DC bias.

 

[sarumbear]

Actually it is a PO box in the UPS Store.

Ha! How opaque - not!

 

[Larry B. Larabee]

I find it curious that the fuses are labeled 1A and 3A but the text below them states to use fuses with the same ratings. I also wonder if the fuse labeled B+ Fuse (the 1A one) is actually connected to the B+. If it is, I hope the fuse holder (and the fuse) are rated for use at that voltage.

Tom

Fuses with a voltage label refer to the minimum voltage necessary to blow the fuse and not have any arcing across the open fuse terminals. So, 600v and a 250v rated fuse is more than adequate.

 

[MakeMineVinyl]

In this happy ending, Bob Carver would also come forward and reveal that the amplifier was not manufactured to his original specification and the design was cheapened.

The one thing that sticks out is that Bob Carver certainly had to know that there was only a 15 watt transformer used in the amplifier by him being present at this event.

The under-specified transformer seems to be the main culprit in the non-realistic specs (or at least the way that most people would interpret the claims of power output).

He very well may be unaware of the safety issues.

 

[Larry B. Larabee]

With no music signal coming out of the amplifier, there is no voltage developed across R53, so it would be impossible for it to factor into setting the DC bias.

How do you usually set the bias on a tube amp that has no meter? Do you know what R53-the 0.1 ohm resistor is there for?
thanks

 

[SIY]

Do you know what R53-the 0.1 ohm resistor is there for?
thanks

Series-derived feedback.

 

[paulbottlehead]

How do you usually set the bias on a tube amp that has no meter? Do you know what R53-the 0.1 ohm resistor is there for?
thanks

Where you see "Cathode" written on the schematic for the 275, there would be a resistor to ground. Ground and the cathode side of that resistor would be wired to test jacks where you could use a meter to measure the DC voltage drop across that resistor and set the current appropriately.

R53 is part of the feedback network used on this amplifier.

 

[john2017]

Quoted from a friend on another forum...

All one has to do is actually talk to or listen Frank to completely understand. After listening to him at Axpona for about 20min. with him slamming Bob from every angle you would understand COMPLETELY!!
I had to get up and leave it was embarrassing !! Frank actually said Bob was a nobody and couldn't design anything with out him. I LOL and said a few words of wisdom as I left the room. I wasn't the only one who walked out. Utterly a HUGE narcissistic EGO that with out Frank there would be no audio world he single handedly built all audio companies.

 

[Doodski]

Quoted from a friend on another forum...

I try and avoid gossip but after the details you've shared here this Frank guy sounds like a class A wanker. I sold carver for about 5 years and it was a joy to sell and the customers enjoyed it too. My friends where buying the gear from me and ran the stuff very hard at weekend house parties. No issues other than one blowing the power supply in a M400 cube. Was a easy fix for the techy.

 

[Madjalapeno]

Would love to know who thought Great.

 

[traderitch]

I find it amusing that this forum doesn't meet your standards. It's one of the most civilised that I'm a member of. Most people are on here for their hobby/entertainment. Your repeated attempts to try and moderate people's responses are doomed to failure.

Salty Dogg,

I am not sure why you think the forum 'doesn't meet' my standards.

I too have belonged to forums that go off the rails with personal attacks (My participation has been limited here - not sure if it is common occurrence)

Vintage SS (and within the past five years Tube) audio equipment have been my passion - even since, what we now refer, to as Vintage Gear
was brand new. I have bought and refreshed much of the gear that I desired but couldn't afford as a teen. (Proton/hk/McIntosh/Marantz/Sansui)

You are right - in no way is it my place to moderate responses. That is the responsibility of the site moderators.
Please tell me you are cognizant of the posts I have issue with - Telling an owner that he/she got conned, that what they own is a p.o.s. etc.
(Those posts tend to get 'liked' by those in the bubble.)
If you feel those are helpful please explain - failure has never been an option for me.

I look forward to additional posts by those with expertise who may have a solution to the problems with this unit.

For example:
If the transformers are indeed undersized - what size transformer would produce the 'marketing rated' specs?
Would they fit in the current covers?
Would up/down stream components need to be replaced with higher values or tolerances?
Is there an easy way to correct the 'safety' issues?

 

[paulbottlehead]

For example:
If the transformers are indeed undersized - what size transformer would produce the 'marketing rated' specs?
Would they fit in the current covers?
Would up/down stream components need to be replaced with higher values or tolerances?
Is there an easy way to correct the 'safety' issues?

It would certainly be worth someone's time to try 75W+ rated OPTs. I do not believe they will fit in the covers, as the 50W rated Edcor push-pull transformers just barely slide in there.

The compensation networks in the amp would undoubtedly be wrong for a different OT.

 

[Blumlein 88]

Salty Dogg,

I am not sure why you think the forum 'doesn't meet' my standards.

I too have belonged to forums that go off the rails with personal attacks (My participation has been limited here - not sure if it is common occurrence)

Vintage SS (and within the past five years Tube) audio equipment have been my passion - even since, what we now refer, to as Vintage Gear
was brand new. I have bought and refreshed much of the gear that I desired but couldn't afford as a teen. (Proton/hk/McIntosh/Marantz/Sansui)

You are right - in no way is it my place to moderate responses. That is the responsibility of the site moderators.
Please tell me you are cognizant of the posts I have issue with - Telling an owner that he/she got conned, that what they own is a p.o.s. etc.
(Those posts tend to get 'liked' by those in the bubble.)
If you feel those are helpful please explain - failure has never been an option for me.

I look forward to additional posts by those with expertise who may have a solution to the problems with this unit.

For example:
If the transformers are indeed undersized - what size transformer would produce the 'marketing rated' specs?
Would they fit in the current covers?
Would up/down stream components need to be replaced with higher values or tolerances?
Is there an easy way to correct the 'safety' issues?

You don't build a 75watt amp with 15 watt rated transformers. Did I really need to point it out for you?

 

[Rottmannash]

The Chief Designer is Bob Carver. Or so this says.

Then it says a lot of stuff like the 275 being really 90 watts. A tribute to Frank McIntosh, and later Stu Hegeman of HK Citation fame. Wow!

And again the idea it can repair a defective output tube, and this is the first place I noticed they claim a tube life of 26 years (45 years in the 350 model). I think I'll buy one, get all the defective output tubes I can, play them a few hours in the 275 until they are repaired and then sell the tubes for a profit. What do you think?

Great business model-wonder why BC didn't think of that?

 

[pseudoid]

Indeed! Here's an example: View attachment 179721

A lot to be said about this “ONE” that 'revolutionized' things:

Evolution Timeline of the “ONE”:
1925: Charles Ducas, an American inventor, patents the first “ONE” design when he stencils conductive materials onto a flat wooden board.
1936: Paul Eisler develops the first “ONE” for use in a radio set. Then, in 1943, he patents an advanced “ONE”.
1944: The United States and Britain work together to develop proximity fuses (based on “ONE”) for use in mines, bombs, and artillery shells during WWII.
1948: The United States Army releases the “ONE” technology to the public, prompting widespread development.
1950s: Transistors are introduced to the electronics market, reducing the overall size of electronics, and making it easier to incorporate the “ONE” and dramatically improving electronics reliability.
1950s-1960s: The “ONE” evolves into double-sided “ONE” but not called "TWO".
......

I elected myself to give the “ONE” the homage that it deserve and that we take for granted!

 

[BlackTalon]

I merely stated that people that chime in to say the equipment in question is a pos are not really
adding anything of value to those who are here to learn more about its shortfalls.

The shortfalls were outlined in the OP. We are free to post what we want. This thread does not exist for you. Yet there are plenty of posts here where people have gone out if their way to explain, reexplain and explain again things for you.

These amps are a joke. I don't own one, and I never will. I don't need to own one to discuss how poorly made these are.

 

[restorer-john]

Would love to know who thought Great.


View attachment 179792

I felt sorry for the little Crimson 275 and gave it a sympathy vote. It's hardly its fault their makers installed such tiny transformers. If only it'd been given a chance, it might have been something special.

I coulda had class. I coulda been a contender...

​

 

[alashikata]

View attachment 179471
This is what was used in the Carverfest version. I'm a little hesitant to take anything apart on the one I bought since it's going back, but they do weigh the same.

Is this Carver Crimson 275? KT120 needs 1.95A filament each tube and 4 of them need 7.8A and 0.6A for other 3 tubes so the total is 9.6A. While your pic show only 5.5A for brown wires where it's not enough current to run the tubes Blue wires is 50v for negative bias -41v. Red 265vAC is correct that would give B1 voltage double at 685vDC and B2 at 350vDC. This seems like a scam.