Bob Carver 180 Mono-blocks perform superbly

If anyone hasn't noticed, the Carver Black Beauty Amp won Editors Choice and Product of the Year awards by The Absolute Sound for 2012. And for some of you trying to figure out what boutique capacitor the amp uses (it doesn't), I would pay more attention to the sound of the amp than name brand parts. I put Vcaps for output coupling and am not sure they made a significant difference. It is the best amp I've ever used. If you really want to hear a significant upgrade in sound, get a pair of Psvane 12AX7 and 12AT7s, which are magical in this amp. Sound better than NOS Telefunken smooth plate 12AX7 and RCA 12AT7s.

The Absolute Sound Editors Choice and Product of the Year was also given to the NuForce Reference 9 switching amplifiers reviewed by TAS Senior Writer Chris Martens in 2009. Within a few months a small group of that periodicals writers, with the exception of Martens, panned the product in an unbelievably half assed "class D shootout."

On the other hand I've owned both the NuForce and now the Carver VTA 180's which are very similar to the more powerful Black Beauty's which were reviewed by Executive Editor Jonathan Valin in the December 2012 issue. My experience with both sets of mono blocks was and is very similar to the descriptions by both Martens and Valin.

I have a pair of Voskhod 12AX7 that I have yet to try.

Voskhod 12AX7 for only $1.70! Let us know how it sounds. However, it looks like you have to rewire the filament connection because it only accepts 6.3 V, not 12.6 V. Not sure how the 12AX7s in the Carvers are connected.

Vicdamone, how does the NuForce Ref 9 sound compared to the Cherry 180? I have not had Class D amps in my system. I've heard them in other systems and at shows, but the sound never won me over.

So why are "vintage transformers" better than the ones wound now, specifically for these amps? Old is good?

Hi Ait, I did not say vintage transformers are better. For the eBay Cherry 180s, Bob used pie wound vintage transformers that he bought when he was in college, I believe. Pie winding was important in the old days when the "iron" wasn't as good as present day core material. In the pre-transistor era, transformer designers had to rely more on their winding technique than the core material to get good frequency response. But pie winding is more time consuming and difficult to do. This is what Bob told me.

Drac, well the difference is a lot like solid state and tube, so a comparison is not what I would call useful. When class D became recently popular there were some who wrote of hearing a tube like quality in the sound of their switching amp. I've had nine different switching amps in my system and none of them came close to sounding tube like.

My NuForce mono's began as the original Reference 9 SE and were upgraded to version 3. Generally speaking switching amplifiers are becoming more refined with the forward glassiness getting worked out. Channel Island, Nuforce, the big Rowlands, and the Hypex nCores to name a few.

I use switching amplifiers to power a pair of Avalon Acoustics Monitors in my studio. Their presentation that many find objectionable is exactly what I want from an amplifier in my studio environment.

I have used them in my main system but I prefer the relaxed presentation that only tubes provide for extended listening.

Switching amplifiers are simply a new amplifier option that many have found to meet their needs. The credibility and contempt by some in this hobby towards switching amplifiers is becoming more shortsighted. Design and technical improvements improve their sonic characteristics while maintaining their extraordinary efficiency and economical cost IMO.

I didn't know about the voltage differences in those tubes. Could that cause a problem? They were so inexpensive maybe I'll just forget about them.

Hi Vic, thanks for the description of sound of the NuForce.

I would contact Bob Carver, LLC and make sure those tubes won't cause a problem if you decide to directly plug them into your amp without rewiring.

Has anyone tried the cherry 180 amps with Thiel 3.6 speakers? Any opinions if the Thiels would be better driven with the Black Beauty amps? I am currently driving the Thiels with an older Bryston 4b (200w/ch into 8ohms) which has been a good combination.

According to Bob Carver, there should not be a significant difference in sound between the two amps except for the extra headroom of the BBs. I have heard that the KT120s on the BBs may sound a little sweeter up top than the stock KT88s in the Cherry 180. But you got so much choice in KT88s, you could probably get the sound you're looking for by tube rolling. You can't with the KT120, which is only made by one manufacturer. Based on what I've heard from the latest Bryston amps in different systems (but not in my own), I can almost guarantee you that Bob's amps will have better sound staging/imaging, more harmonically correct and less fatiguing sound than the Bryston. Bryston will probably have tighter bass. That's my edumacated guess based on my experience. I think Thiels relatively lean sound will benefit from a good tube amp.

Looking at the stereophile measurements of the 3.6 the impedance dips to 4 ohms at approximately 50Hz then continues down to 3 ohms for the remainder of the test and occasionally bottoming at 2.3 ohms.

While this might be a problem for many tube designs the Carver VTA's have a 2 ohm tap if needed. My Eidolons are a load that dips below 4 ohms and the 8 ohm tap sounds great.

I'd suggest calling Underwood HiFi, they may have experience with the 3.6.

Have anyone try KT120s with Cherry 180?
I read that KT120 has sweeter sounding like EL34 on steroid.
KT120 has same spec as KT88 ? aka Super KT88
As long as we bias these just like KT88, we're not stress the 180' transformer ?
I would live to try these on Cherry 180 - I currently roll mine with Gold Lion reissued KT88. Definitely step up sounding from stock Shuguangbtubes
TIA
Thuan

I might add that I'm a bit disappoint to see KT88 tube bases of these Cherry 180 are not ceramic. The KT88s are seated loose in these plastic tube bases. At $8k, ceramic bases should be used. Also speaker binding post are lower grade IMO- solid copper, Cardas type, would be better. My Cary 805C mono have better build, fit'n finish.

Anyone rolled the 12AX7 and 12A7? The best I've tried so far is the Psvanes. They sound better to me than the NOS Telefunken smooth plate 12AX7 and RCA 12AT7 combination.

I have Cryoed Voskhod 12AX7 and NOS RCA 12AT7. Very pleased with its sound. But I don't have Tele 12AX7 to compare. I'm hunting for a pair of Sylvania Gold brand 5751WA to try it out, still looking

Thuan, are those the Voskhod 12AX7VKA?

Wondering if they are the same 12AX7 that Dracule checked the specs and posted above, they accept only 6.3 volts?

Yes, they're. I wonder about that post too. But it seems working fine. Exact same tube that one of the reviewers mentioned

Yeah, that's were I read about them but I forget which review.

Here's the link :)
http://www.enjoythemusic.com/superioraudio/equipment/0512/bob_carver_cherry_180_tube_monoblock_amplifier.htm

I recently got a pair of the Cherry 180s albeit in black. Been enjoying them for a few months now just with stock tubes. After reading this thread I will certainly upgrade the 12AX7 and 12AT7 input tubes to something better.
I was wondering if anyone has also upgraded the KT88 output tubes as well? Or would the benefits be only marginal?
Thanks in advance.

I've heard the golden lion KT88 reissues are very good. I'm thinking of getting them.

I mentioned in my post on Jan 22 that I have Gold Lion for power tube- Great upgrade for money. I'm thinking about getting Black Treasure or Psvane when I have some extra cash :)
Roll 12 tubes would cost a small fortune if getting premium grade
Check tube-sale.com for various grades available

Thanks guys. I missed that earlier post Thuan. Will certainly get some Gold Lions when funds permit. I have hooked up the Bobs to my Maggie MMGs with great results. I need to turn the volume up to around half way to get decent spl but the Bobs don't seem to be struggling at all.

Maggies do soak up power like a sponge...can you describe more in detail how the Carvers sound on them?

My MMGs were previously powered by an ME 550 solid state power amp. Using a Dynavector L300 preamp the sound with the Maggies was simply superb to my ears. Quite effortless with plenty of punch. With the Bobs connected the soundstage is more open and I hear more of the harmonics of instruments and vocals. The ME/Dyn combo without doubt has more bass slam but lacked the air and upper extension of the Bobs. As mentioned before the Bobs do need to be turned up a fare bit for the MMGs to sing though.

These are my views with all stock standard tubes supplied with the Bobs so things could change in a hurry!

Thanks Vmhf. Bob amps used to come with NOS smooth plate Telefunken 12AX7 and RCA or GE 12AT7, which were a great combination. From what I understand, the current signal tube are crappy Chinese signal tubes. If you can get the high quality Chinese Psvane 12AX7/12AT7, you will even surpass the NOS combination. More extension in the bass/treble, more air, better soundstaging and imaging, etc. For Maggies, may be the 300 watt Black Beauty may be a better match.

I have a little secret to share with you if you want to improve the sound more than what high quality signal tube can do. And it's affordable. You will significantly increase bass impact and dynamics (may rival your SS amp), among all the other improvements I've talked about. Replace the stock volume control pots in the amp with Gold Point stepped attenuators (~$160). You will be shocked at the improvement. If you are handy with soldering iron or have a local tech, this is the best mod I've done on this amp. A more expensive mod is to put in four 0.22 uF Teflon Vcap as output caps. These two mods will take these amps to a whole new level. Bob's circuitry is rock solid and installing high quality key parts can make this amp sound just incredible.

Good one Drac. I haven't been under to hood on my 180's. Is that two or four Teflon Vcaps per mono block? Will the Vcaps be replacing some existing caps?

You are wealth of knowledge Dracule1. Thanks heaps for the advice.
I am looking into the Gold Point stepped attenuators now. I noticed the same guys also make passive preamps using their attenuators. Any thoughts on using a passive preamp with the Cherry 180s?
In fact any thoughts on using preamps with these great amps would be much appreciated. I am currently using my two sources, CD and phono, into the Bobs but need to physically switch cables every time I want to hear the other source.

Vicdamone, you will need two Vcaps per monoblock, so four total. I have the tin foil, not the copper foil Vcap. I think an even better cap would be the copper PIO Duelund CAST caps, but I can't afford them right now. They're on sale at Partsconnexion.com.

Vmhf, you will get the best result installing the Goldpoints within the input of the amp. Having an external passive will degrade the sound compared to the above. Believe me, I've tried. If you want remote, you get the the Bent Audio remote control kit for the Goldpoints.

If you want to use both your phono and CDP without having to switch cables, I would recommend an active preamp. But you need to make sure the active preamp doesn't have too much gain, because Bobs amps have input sensitivity of 1.25 V for full power.

After you hear the Goldpoints in the amp, it's hard to go back to anything else because the sound quality so darn good. I'm willing to physically switch cables and go without remote for the best sound possible.

Vicdamone, yes the Vcaps will replace the stock 2.2 uF output coupling caps.

Thanks Dracule1.

I am more than happy to physically switch cables too. In fact I don't have any room on my racks to accommodate a preamp anyway!

Currently I have some upgraded KT88's on the way and have been listening to a variety of 12AX7's and 12AT7's with remarkable improvements to the sound!
Its all good fun and very satisfying.

Cheers.

Hey Vmhf, let us know of your impressions on the different 12AX7/12AT7s you've tried.

Hi Dracule 1: You said in an earlier post that the output coupling caps were a 0.22 uf rating, then posted 2.2 uf in a later post. Which is it? If they're 2.2 uf, would there be enough room to fit the Deuland Cast caps in there? Thanks, Jeff

Hi Dracule1. Will give my opinions on the input tubes I have shortly!
Just wondering which Gold Point Stepped Attenuators go with the Bobs. There's quite a few choices. Thanks again!

Jeff, the output coupling caps are 0.22 uF. There is a feedback cap in there that is 2.2 uF. All you have to do is pop the hood and check.

Vmhf, you need two MiniV, 100 kOhm, mono version. $79 each.

http://www.goldpt.com/prices.html

Thanks Dracule1.

After rereading the manuals Warrantee the idea of voiding a seven year warrantee gives me second thoughts of incredibly intriguing modifications. Enjoy.

Vic, I understand your concern. Personally, I think the Goldpoint mod would be the easiest and most bang for the buck improvement. Carver should offer this as an upgrade option.

Carver 305s are now listed in Jonathan Valin's reference system at he end of the Audio Research Corp. trio review in the January 2013 edition of TAS.

As Dracule mentioned earlier in this thread the Carver 305 are also listed in the TAS "Upper-End Tube Power Amps of the Year," in that same January 2013 issue.

Of course his stable is in a constant state of change, still, that's some prestigious power amplifier company to be in.

This is one of only two products I've purchased without a physical audition. Thanks goes mainly to those who participated and shared their impressions in this thread.
Also the Peter Breuniger video review of the VTA 180s driving the difficult load MBL's.
The Dick Olsher review for the recent historical collaborative development of the amplifiers and the formation of Carver LLC.

Bob is awesome. I'm glad he's in high end tube audio again. Last time was back in the 80's with is Silver 7 mono blocks.

Don't forget Bob's superb "Sunfire Classic Vacuum Tube Control Center," the preamp design from the mid '90's which has become one of those rare components which, just 10 years after the last one rolled off the line, is selling for more than it sold new.

Man! You're right. I having a total recall. I don't use active preamps, so it slipped my mind.

This becomes an interesting read towards the bottom.

http://db.AudioAsylum.com/mhtml/m.html?forum=tubes&n=231311&highlight=6al5&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fforum%3Dtubes%26searchtext%3D6al5

Ah yes, I remember this story of Bob and Stu Hegeman. The best designers of the glory tube years would never consider designing a SET amp, including Bob. It was PP class AB amps all the way, and to my ears they are more neutral than any SET amp I've heard. Bob is an entertaining story teller. Thanks for the link Vic.

Bob Carver tube amp owners should unite and ask for stepped volume control and better output coupling caps as upgrade options. They're easy upgrades that significantly improves the sound.

Hi Dracule. Despite your wholehearted recommendations of upgrading the vol control and output caps I have decided to leave the amps as is mainly for warranty issues. I am still waiting for my upgraded KT88s and a few more input tubes to arrive. Fun days ahead!

I do have a question for 180 users though. If using a CD player with volume control directly connected to the Bobs, who sets the Bobs vol knobs to max and adjusts volume via the CD player? Previously I had the CD player output maxed out and used the Bobs to adjust volume to each channel. But lately I have been having problems with imaging with this approach. Sound quality wise I can't seem to tell a difference. Cheers.

Vmhf, I understand your warranty concern. As far as your CDP volume issue is concerned, it depends on the quality of the the volume control circuit of the CDP. If it is high quality, I would set Bobs vol control to max which will almost effectively bypass the amp's stock pot. If you decide to install the Gold Point attenuator in the future, I would set the CDP vol to max and use the GP to control the volume. Nothing I've tried so far beats the GP installed in the amp.

VmhF, great news! Bob Carver has informed me replacing the stock volume pot with the Gold Point stepped attenuator by a qualified professional will not void the warranty on the amp.