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joeinid
April 13, 2013, 06:31 PM
Here is a nice review of this great little amp. I love mine.


http://dagogo.com/bob-carver-black-magic-vta-20s-tube-amplifier-review

http://dagogo.com/wp-content/uploads/2013/03/20W_frontangledview-copy.jpg (http://dagogo.com/wp-content/uploads/2013/03/20W_frontangledview-copy.jpg)

A/V Solutions
April 13, 2013, 08:43 PM
Joe.....you get the Black Magic and Cornwall's playing yet?

joeinid
April 13, 2013, 08:46 PM
Hi Jeff,

Not yet. Hopefully in the next couple of weeks. I've actually been using my TADs lately. It's pretty awesome on them too. I'm really enjoying my late night listening sessions.

Paul
April 13, 2013, 10:03 PM
Great...I love the EL84 sounds especially mate with the Cardas Golden Reference I/C.

Thank you for sharing.

joeinid
April 14, 2013, 02:01 AM
Great...I love the EL84 sounds especially mate with the Cardas Golden Reference I/C.

Thank you for sharing.

Paul it's a wonderful little amp.

dlb2
April 14, 2013, 09:12 AM
I bet that sounds great Joe. Have you tried any different brand of tubes besides that OEM ones? I think the only thing that would bug me is reaching around back to turn it on and off. What's the knob for?

joeinid
April 14, 2013, 10:39 AM
I bet that sounds great Joe. Have you tried any different brand of tubes besides that OEM ones? I think the only thing that would bug me is reaching around back to turn it on and off. What's the knob for?

It really does sound great. I have not tried different tubes. The EL84M's it comes with are higher voltage versions (I hope Jeff Whitlock confirms this) because that's how they achieve 20 wpc. I think regular tubes could cause a problem. The knob adjusts the input volume. It's not a volume control in the strictest sense but can be used like that, and I do.

VACUUM TUBES

The EL84M output tubes do not need to be matched. That's because the DC restorer circuit eliminates that need.

Please note, we have selected the “M” version of the EL84 because it has a higher plate volt-age rating than the “non-M” tubes made by many manufacturers.
This is how we achieve a full 20 watts per channel output power by using just one pair each of EL84M tubes. We do not guarantee that replacing these tubes with non-M EL84s will work. Red plating may occur (meaning the tubes will glow red hot)


Looking at the amplifier from the front, the two smaller 12AX7 tubes go right behind the “roll bar”, the EL84M tubes are installed in the four sockets behind them.


VOLUME CONTROL

Under normal circumstances, this control should be left in the maximum (fully clockwise) position. If you
have a noisy preamp, turning it halfway down and centering it at the 12:00 o'clock position will reduce
the preamp noise by half, or 6 dB. It should always be turned all the way down when connecting or dis-
connecting any input or output in your system. Connect RCA patch cords from your preamp to the RCA
audio input jacks on the back of this unit.


Note:

You may also directly connect a piece of “line level” source equipment to this amplifier with no
preamp and use the volume pot on the amp to adjust the volume. Phonographs cannot be directly to this
amplifier without the use of a phono-prestage preamplifier.

A/V Solutions
April 14, 2013, 11:00 AM
It really does sound great. I have not tried different tubes. The EL84M's it comes with are higher voltage versions (I hope Jeff Whitlock confirms this) because that's how they achieve 20 wpc. I think regular tubes could cause a problem. The knob adjusts the input volume. It's not a volume control in the strictest sense but can be used like that, and I do.

VACUUM TUBES

The EL84M output tubes do not need to be matched. That's because the DC restorer circuit eliminates that need.

Please note, we have selected the “M” version of the EL84 because it has a higher plate volt-age rating than the “non-M” tubes made by many manufacturers.
This is how we achieve a full 20 watts per channel output power by using just one pair each of EL84M tubes. We do not guarantee that replacing these tubes with non-M EL84s will work. Red plating may occur (meaning the tubes will glow red hot)


Looking at the amplifier from the front, the two smaller 12AX7 tubes go right behind the “roll bar”, the EL84M tubes are installed in the four sockets behind them.


VOLUME CONTROL

Under normal circumstances, this control should be left in the maximum (fully clockwise) position. If you
have a noisy preamp, turning it halfway down and centering it at the 12:00 o'clock position will reduce
the preamp noise by half, or 6 dB. It should always be turned all the way down when connecting or dis-
connecting any input or output in your system. Connect RCA patch cords from your preamp to the RCA
audio input jacks on the back of this unit.


Note:

You may also directly connect a piece of “line level” source equipment to this amplifier with no
preamp and use the volume pot on the amp to adjust the volume. Phonographs cannot be directly to this
amplifier without the use of a phono-prestage preamplifier.


Confirmed......

joeinid
April 14, 2013, 11:01 AM
Confirmed......

Thanks Jeff.

You were right about this little amp. Thank you again.

dlb2
April 14, 2013, 01:08 PM
Thanks for the info. Joe. :)

joeinid
May 9, 2013, 06:01 PM
1202

TubeBias
May 9, 2013, 07:59 PM
I was admiring this earlier today.Where did you buy yours if you don't mind me asking?
Sadly I have no dealers nearby to give it a listen.

joeinid
May 9, 2013, 08:06 PM
I was admiring this earlier today.Where did you buy yours if you don't mind me asking?
Sadly I have no dealers nearby to give it a listen.

I bought it from Jeff Whitlock of A/V Solutions here on the forum. Awesome dealer!

Home Page (http://www.avsolutionsca.com/)

socfan12
May 9, 2013, 08:20 PM
I bought it from Jeff Whitlock of A/V Solutions here on the forum. Awesome dealer!

Home Page (http://www.avsolutionsca.com/)


+1000 on that!

Dewster
May 9, 2013, 08:22 PM
I was admiring this earlier today.Where did you buy yours if you don't mind me asking?
Sadly I have no dealers nearby to give it a listen.

I think this little thing Joe has for the longest in his possession :sneaky:

joeinid
May 9, 2013, 08:30 PM
I think this little thing Joe has for the longest in his possession :sneaky:

Pretty close to it.

TubeBias
May 9, 2013, 08:42 PM
I bought it from Jeff Whitlock of A/V Solutions here on the forum. Awesome dealer!

Home Page (http://www.avsolutionsca.com/)



Thank you.

sharkmouth
May 9, 2013, 11:23 PM
I think this little thing Joe has for the longest in his possession :sneaky:


Pretty close to it.

Ha!! He's the only bloke I know of that is using a darTZeel amp for cable lifters, you're too much sometimes Joe. Then again I was really proud of myself using a milk crate, 2x4 & a brick for a rack for my MSB Diamond DAC. :fingers:

joeinid
May 9, 2013, 11:26 PM
Ha!! He's the only bloke I know of that is using a darTZeel amp for cable lifters, you're too much sometimes Joe. Then again I was really proud of myself using a milk crate, 2x4 & a brick for a rack for my MSB Diamond DAC. :fingers:

Ha! Hey, nothing works better than a Dart to raise your cable :)

Dewster
May 9, 2013, 11:35 PM
Ha!! He's the only bloke I know of that is using a darTZeel amp for cable lifters, you're too much sometimes Joe. Then again I was really proud of myself using a milk crate, 2x4 & a brick for a rack for my MSB Diamond DAC. :fingers:

You know when you've reached "Baller" status :snicker:

CDLehner
July 15, 2014, 02:28 PM
I realize I'm pulling this thread from the grave a bit; but I just took one of Joe's Black Magic, off his hands...and I couldn't be more excited!

I've always had an eye on this little beauty; because I think it looks like a million bucks...and I'm hoping it sounds as good too.

I've always wanted to "get small"...with a SET, and some really high-efficiency speakers. And while I realize this isn't a SET; I am hoping for a little EL-84 magic...paired with some full-range Omega A8s I scored.

Not replacing the 30.1s certainly (or the KEFs, lol); but...as a sweet, little 2nd system (or 3rd, or 4th...depending on how you count these things). As I said...couldn't be more excited :celebrate008_2:

joeinid
July 15, 2014, 02:34 PM
Thanks Chris,

It could not have come at a better time. I guess you should have it in your hands soon so please keep us updated.

Enjoy it. I'm sure it's not even broken in yet because I never used that one. :)

CDLehner
July 15, 2014, 02:44 PM
Thanks Chris,

It could not have come at a better time. I guess you should have it in your hands soon so please keep us updated.

Enjoy it. I'm sure it's not even broken in yet because I never used that one. :)

Happy to contribute...to the joeinid-strad-fund :)

Amp arrives today; Omegas not until Thursday :(

the professor
July 15, 2014, 02:47 PM
Nice

Congrats

dlb2
July 15, 2014, 02:48 PM
Thanks Chris,

It could not have come at a better time. I guess you should have it in your hands soon so please keep us updated.

Enjoy it. I'm sure it's not even broken in yet because I never used that one. :)

Joe, you're my hero! :heart:

Definitely let us know how you like it Chris.

CDLehner
July 15, 2014, 03:09 PM
Joe, you're my hero! :heart:

Definitely let us know how you like it Chris.

You bet; and pix!

joeinid
July 15, 2014, 03:54 PM
That should be a wonderful combination.

CDLehner
July 15, 2014, 07:46 PM
Magic in da house! Here's a little teaser pic (and if you want to know about the rest of the set-up; just take a peek at the sig :)

6897

http://audioshark.org/attachment.php?attachmentid=6897&d=1405468027

socfan12
July 15, 2014, 08:07 PM
Joe, you're my hero! :heart:

Definitely let us know how you like it Chris.

+1, on both counts!:)

joeinid
July 15, 2014, 08:10 PM
I never even opened the box. :(

dlb2
July 15, 2014, 08:33 PM
I never even opened the box. :(

Hey, 1 out of 2 isn't bad!


Time to pop some tubes in that beauty Chris. :celebrate008_2:

Dpod4
July 15, 2014, 08:59 PM
My trusted dealer swears by these and he carries stuff in the stratosphere

Jack
July 15, 2014, 09:00 PM
Joe

It would be an interesting comparison/test when you get the RM-10 sorted out to see what you think about the two designers different execution of the EL-84 amplifier. Just need to have a speaker on hand that will play nice with both of them.

joeinid
July 15, 2014, 09:59 PM
:panic:

Ha!


Hey, 1 out of 2 isn't bad!


Time to pop some tubes in that beauty Chris. :celebrate008_2:

CDLehner
July 16, 2014, 07:18 AM
Hey, 1 out of 2 isn't bad!


Time to pop some tubes in that beauty Chris. :celebrate008_2:

Agreed! The pre-amp tubes (ax7s), literally say 12ax7(b) and 'China'; and that's it...lol. By all accounts, that makes them Shuguang; and while I'm not denigrating them...we can do better, yes? I have some NOS Mullards, that I'll pop in...once the Omegas drop.

As for EL-84s; that's a new beast to me. I know the BM, has 'M' version EL-84s, which are supposed to have a higher current tolerance; but I don't think I have to worry about running out of juice, with the 96db A8s :) So...I am open to suggestions!

Now...as soon as Joe, sends me that remote; I'll be all set. :P

joeinid
July 16, 2014, 08:56 AM
Ha!

I'll get right on it. :cool:

Just be careful with tube substitution.


Agreed! The pre-amp tubes (ax7s), literally say 12ax7(b) and 'China'; and that's it...lol. By all accounts, that makes them Shuguang; and while I'm not denigrating them...we can do better, yes? I have some NOS Mullards, that I'll pop in...once the Omegas drop.

As for EL-84s; that's a new beast to me. I know the BM, has 'M' version EL-84s, which are supposed to have a higher current tolerance; but I don't think I have to worry about running out of juice, with the 96db A8s :) So...I am open to suggestions!

Now...as soon as Joe, sends me that remote; I'll be all set. :P

CDLehner
July 16, 2014, 02:50 PM
Ha!

I'll get right on it. :cool:

Just be careful with tube substitution.

What's your concern, tube-wise Joseph?

I already have the Mullard CV4004s; I think I'll also try some TungSol in the pre-amp spot.

As for EL-84s; Tungsram sound intriguing...and you can never go wrong with Gold Lions!

joeinid
July 16, 2014, 03:24 PM
I think the version in the Carver are run harder. I am not sure if that means increased voltage too. I've never tried rolling them.

dlb2
July 16, 2014, 04:54 PM
What's your concern, tube-wise Joseph?

I already have the Mullard CV4004s; I think I'll also try some TungSol in the pre-amp spot.

As for EL-84s; Tungsram sound intriguing...and you can never go wrong with Gold Lions!

Don't know what you're looking at price wise on the EL-84's, but you can't go wrong with some Amperex or Mazda's. Of course there's always the Telefunken's. It all depends on what you like. Shoot Nikolay at Tube Maze an email, he always does a nice job with recommendations.

joeinid
July 16, 2014, 05:11 PM
Carver’s circuit topology is fairly simple. The input signal first passes through a 250k ohm volume control and is then amplified by one half of a 12AX7. The second half of the 12AX7 is configured as a cathodyne phase-splitter. That’s it—no driver stage is used. The push-pull output stage is pentode connected and uses a pair of self-biased El84Ms per channel. I estimated the anode dissipation to be about 11 watts, which is well within the 14W maximum rating of an El84M. Bob Carver indicated that the bias is actually set for a nominal plate dissipation of 10.5 watts to allow for tube variation. Note that the El84M is a mil- spec version of the standard sovtek El84 with extended voltage tolerance, improved plate dissipation, and rugged construction.

I would not recommend substitution of a standard El84, as it is only rated for a maximum dissipation of 12 watts.


http://www.theabsolutesound.com/articles/bob-carver-vta20s-black-magic-power-amplifier/

CDLehner
July 16, 2014, 08:30 PM
Carver’s circuit topology is fairly simple. The input signal first passes through a 250k ohm volume control and is then amplified by one half of a 12AX7. The second half of the 12AX7 is configured as a cathodyne phase-splitter. That’s it—no driver stage is used. The push-pull output stage is pentode connected and uses a pair of self-biased El84Ms per channel. I estimated the anode dissipation to be about 11 watts, which is well within the 14W maximum rating of an El84M. Bob Carver indicated that the bias is actually set for a nominal plate dissipation of 10.5 watts to allow for tube variation. Note that the El84M is a mil- spec version of the standard sovtek El84 with extended voltage tolerance, improved plate dissipation, and rugged construction.

I would not recommend substitution of a standard El84, as it is only rated for a maximum dissipation of 12 watts.


Bob Carver VTA20S ?Black Magic? Power Amplifier | The Absolute Sound (http://www.theabsolutesound.com/articles/bob-carver-vta20s-black-magic-power-amplifier/)

Oh yeah; well I think 'ole Dick Olsher, is just scurred. ;)

No...it's a point well-taken Joe; and thanks for the heads-up. I'll discuss it, with some gurus; and make sure they don't think I'll blow my little Magic up.

Jack
July 16, 2014, 08:51 PM
Chris

You might want to contact Roger Modjeski or his people at his tube store and see what they say. I know that Roger's tube testing standards are probably the highest in the Industry and he has been selling the same EL-84 based amp for over 25 years with an output of 35 WPC. He may be familiar with Carver's design and can give you some guidance as to what tubes to stay away from.

Music Reference | RAM Tubeworks (http://www.ramlabs-musicreference.com/)

joeinid
July 16, 2014, 09:27 PM
+1

Excellent advice Jack.


Chris

You might want to contact Roger Modjeski or his people at his tube store and see what they say. I know that Roger's tube testing standards are probably the highest in the Industry and he has been selling the same EL-84 based amp for over 25 years with an output of 35 WPC. He may be familiar with Carver's design and can give you some guidance as to what tubes to stay away from.

Music Reference | RAM Tubeworks (http://www.ramlabs-musicreference.com/)

CDLehner
July 16, 2014, 09:45 PM
Hmm...from the man himself:

The Russian EL84M tube types are a copy of the 7189 Military Spec tube type that have a larger bottle, and more double the getters than a standard EL84 tube type...

These EL84M sound better than the standard EL84 tube type, and are highly recommended.

But what fun is it, if I can't r o l l?

Jack
July 16, 2014, 10:22 PM
If by the "man himself" you mean Bob, I wouldn't pay much attention to it. I would seek the opinion of a long term tube amp designer instead of one that moves from one business model to the next. His "simple" circuit should be easily interpreted by someone who has designed tube amps long term or a competent tube amp tech.

CDLehner
July 16, 2014, 10:47 PM
If by the "man himself" you mean Bob, I wouldn't pay much attention to it. I would seek the opinion of a long term tube amp designer instead of one that moves from one business model to the next. His "simple" circuit should be easily interpreted by someone who has designed tube amps long term or a competent tube amp tech.

Ouch; harsh words, for Mr. Carver.

But actually...that was lifted from Roger Modjeski's site.

Jack
July 16, 2014, 11:00 PM
Chris

Not being harsh about Bob, but he has in fact "moved around" a lot with a lot of different company structures. As to the tubes if Roger says the EL-84M's are more durable, then I would believe him. In every tube class their were consumer tubes and Military spec'ed tubes. The Mil spec tubes had to have a guaranteed life span according to the contract. Consumer tubes had no such guaranty.

CDLehner
July 16, 2014, 11:07 PM
Chris

Not being harsh about Bob, but he has in fact "moved around" a lot with a lot of different company structures. As to the tubes if Roger says the EL-84M's are more durable, then I would believe him. In every tube class their were consumer tubes and Military spec'ed tubes. The Mil spec tubes had to have a guaranteed life span according to the contract. Consumer tubes had no such guaranty.

Well...durability is one thing; but he says...and I quote "these EL84M sound better than the standard EL84 tube type". That's pretty definitive stuff!

Oh well; maybe I'll have to buy a second EL-84-based unit...just to do some rolling :)

Jack
July 16, 2014, 11:36 PM
If the EL-84M's have to meet a contract spec and guaranty then they would be hand picked. The same thing as buying a quad of tubes as opposed to a "matched quad." If you want to try a long term tested EL-84 based amp then try to find a used RM-10. I have owned mine for 14 years and never been disappointed. At 35 wpc, it works with speakers 85db and above. It was a perfect match with Reynaud, Soliloquy, Platinum, Meadowlark and Green Mountain. It even pushed the Vandersteen 2CE Sigs to over 90db in a moderate sized room.

CDLehner
July 16, 2014, 11:45 PM
If the EL-84M's have to meet a contract spec and guaranty then they would be hand picked. The same thing as buying a quad of tubes as opposed to a "matched quad." If you want to try a long term tested EL-84 based amp then try to find a used RM-10. I have owned mine for 14 years and never been disappointed. At 35 wpc, it works with speakers 85db and above. It was a perfect match with Reynaud, Soliloquy, Platinum, Meadowlark and Green Mountain. It even pushed the Vandersteen 2CE Sigs to over 90db in a moderate sized room.

Thanks Jack; I'll keep an eye out. If I decide to stray from the BM; I might try a cheapie Jolida JD102CRC.

Jack
July 17, 2014, 12:30 AM
Chris

I think you can tube roll fairly simply with the Carver. I just think he runs his EL-84/6BQ5's at a higher voltage, which means there life expectancy is less. Rolling the driver tubes won't hurt anything they just may not last very long. At the price of some of the tubes mentioned earlier in the thread you just need to know that going in. Since that amp is "auto biasing", what are they auto-biased at. Roger's amp is biased at 30mv. I would suspect the Carver is a bit higher. I still think I would contact Roger directly at his forum on AC and ask him. He seems to be willing to answer any question about anything tube amp related.

dlb2
July 17, 2014, 08:37 AM
I didn't realize it's self-biasing so you can't just set the bias low before putting in new tubes and then bring it up to the proper level. Like Jack said, you don't want to go blowing out $100-200 tubes as soon as you put them in.



Sent from my mobile.

CDLehner
July 17, 2014, 08:20 PM
Update - Omegas are here! But you'll have to give me a few days, to digest and comment; they are not at all, what I expected! :huh:

Besides...I need to build 'em, some proper stands this weekend.

Milsap195
July 18, 2014, 09:21 PM
6914 Congrats on the baby carvers! I love my big ones especially after Bob modified them for the kt150's. Can't wait to hear your thoughts!