Souped-up Carver Amps

Erik Tracy

RichP714 wrote: »

I think the turn on/off thump gave the m-1.0t a bad rep. There is a fix for that BTW, and it's part of the mk II upgrade.

You'll find champions for just about every model Carver out there. As for me, it's my second favorite overall (slightly edged out by the M-500t).

I think I remember your name from Carveraudio.......there are alot of posts there re all the models. Much pro M-1.0t and much con.

Here's a thread, for example....

http://www.carveraudio.com/phpBB3/viewtopic.php?t=3683&postdays=0&postorder=asc&start=120

There are a few testimonials on my site from owners or people that have auditioned the mk IIs

http://carvermk2.com

Hi Rich,
Yup - I joined up on the Carver forum just a bit back.

The mkII mod is near the top of my audio 'to do' list for 2009!!

I hope to make your queue soon - my old m1.0-t is ready for that tune-up.

And your mods make it into an output monster :eek:

Cheers,
Erik

RichP714

Texas42 wrote: »

Welcome aboard, Rich. Can anything be done to improve the 1.5t? I have one. It is the Mark Levinson ML-2 t-mod, if memory serves correct.

Hi there....I don't work with the M-1.5t, it has vertical boards to accomodate those longer horizontally laid rail caps, so It's harder to get to the components without dissasembly.

One thing that can be done is to disable the 'soft clipping' network, which IMO was a popular experiment back then, but wastes power and doesn't make a transistor sound like a tube anyway.

RichP714

Erik Tracy wrote: »

Hi Rich,
Yup - I joined up on the Carver forum just a bit back.

The mkII mod is near the top of my audio 'to do' list for 2009!!

I hope to make your queue soon - my old m1.0-t is ready for that tune-up.

And your mods make it into an output monster :eek:

Cheers,
Erik

There are a couple of new (old renewed) threads on the Carverforum re the various Carver models, who preferred which and why. One is the thread I pointed to previously, the other (more information there) is:

http://www.carveraudio.com/phpBB3/viewtopic.php?f=8&t=1852

George Grand

The ML-2 was a transistor amplifier. I could be wrong, but I don't think there were any tubes involved.

RichP714

George Grand wrote: »

The ML-2 was a transistor amplifier. I could be wrong, but I don't think there were any tubes involved.

That's correct as far as I know

The 1.5t was modified to match the ML-2
The 1.0t was modified to match the Conrad Johnson tube amp (premier V)

RichP714

RichP714 wrote: »

There are a couple of new (old renewed) threads on the Carverforum re the various Carver models, who preferred which and why. One is the thread I pointed to previously, the other (more information there) is:

http://www.carveraudio.com/phpBB3/viewtopic.php?f=8&t=1852

There's also this thread, although it is specific to the mk II M-1.0t

http://www.carveraudio.com/phpBB3/viewtopic.php?f=49&t=6460

George Grand

Thanks for the links, but I'm not quite that hard-up for company yet.

Good to know that you say I'm right though.

RichP714

I'm back from vacation, and sent an email out to all who expressed interest in having their unit's mk II upgraded.

If everybody (10) on my list goes ahead with it, I'll be booked up until the 1st week of April, so if you get an email, let me know as soon as you can if you:
1. Are staying on the list
2. Want to be bumped down on the list
3. Are no longer interested

Thanks, and Happy new Year!

http://carvermk2.com

inspiredsports

Texas42 wrote: »

Welcome aboard, Rich. Can anything be done to improve the 1.5t? I have one. It is the Mark Levinson ML-2 t-mod, if memory serves correct.

It's too bad this one can't be mkII'd as there are some good deals on these out there now. There's one on eBay currently under $375 ending in a few hours.

RichP714

inspiredsports wrote: »

It's too bad this one can't be mkII'd as there are some good deals on these out there now. There's one on eBay currently under $375 ending in a few hours.

M-1.0t's usually go for even less:

1. the thump fix came out too late and gave the amp a bad rep

2. The rating implies it's a younger brother to the M-1.5, but when benchmarked they're within 10 watts of each other.

I'm not a fan of the 'soft clipping' experiment that was popular at the time the M-1.5 came out; I'm glad Carver dropped it.

inspiredsports

RichP714 wrote: »

. . . not a fan of the 'soft clipping' experiment . . .

I'm not either. NAD used it on the vintage 7600/2600A's I've used for years to drive my SDA's and fortunately it is easily switched off. I'm looking to upgrade to Carver's soon and this thread has really caught my attention.

inspiredsports

I have a few general questions about caps in general. If the top are not convex (or are even concave) and there is absolutely no evidence of goo, discoloration, etc., can they still be out of spec to the point it creates a sonic problem? My 21 year old amps' components look perfect and I can't detect any sonic problems, but I'm just wondering.

RichP714

inspiredsports wrote: »

I'm not either. NAD used it on the vintage 7600/2600A's I've used for years to drive my SDA's and fortunately it is easily switched off. I'm looking to upgrade to Carver's soon and this thread has really caught my attention.

Carver, NAD, I think Onkyo gave it a try as well......didn't make a transistor sound like a tube, DID waste rail voltage and introduce it's own distortions.

http://carvermk2.com

RichP714

inspiredsports wrote: »

I have a few general questions about caps in general. If the top are not convex (or are even concave) and there is absolutely no evidence of goo, discoloration, etc., can they still be out of spec to the point it creates a sonic problem? My 21 year old amps' components look perfect and I can't detect any sonic problems, but I'm just wondering.

Yes, caps degrade over time, it's an inevitable aspect of the chemistry.

The things I mentioned, bulging and leakage, are GROSS indications that the caps have either vented (usually from overheating) or leaked electrolyte sometime in their life.

Either of those things will adversely effect their storage capacity, but a cap that's not been exposed to excessive heat or has a leak will STILL have it's plates degrade over time, and the equivalent series resistance (ESR) will creep up. The best analogy I can think of is how one's joints stiffen with age; they become slower and lose their full range of motion.

They say 20 yrs is about all you can expect from a cap, and that's on a good day The Carver magnetic field supply, with it's triac controlled firing of the primary in bursts, places more extreme ripple currents across the power supply caps than a traditional design.

To the extent that that's a 'sonic problem' is totally up to you and your ears. In other words, I can't guarantee that YOU will hear $300 worth of difference.

All I can do is offer to buy back (+$50) any whole unit I sell, if the owner isn't happy, within 15 days of purchase.

I haven't had a return yet, and some have said that their M-1.0t mk II's sounded BETTER than recently refurbed M-1.5t's, which makes me very happy (that's what this is all about, enjoyment)

RichP714

Carver site! has moved to its new home at:

http://thecarversite.com

F1nut

The one and only original Carver Audio forum is still where it's always been.

http://www.carveraudio.com/phpBB3/

Erik Tracy

I thought this was an appropriate thread to 'revive' as it has to do with a Carver amp I had "souped up" by Rich, who has done previous modifications of some Carver amps.

I was a happy owner of one of the Carver M-1.0t amps - bought back in the early 80's - in fact I have serial number 098 - not that that is any note of worth.

Well, my amp had been part of my 2-channel rig for years until I made the switch to "Home Theater" - where it served as the amp to drive my front mains.

I do quite a bit of 2-channel listening still, and put the amp to some extensive use for CDs, LPs, and digital cable music.

But, seeing as my Carver has been in service for some 20 or so years, it was time to have it checked out and tuned up.

I had read that the typical service life of capacitors in amps was about 20 years, and I had also read some good 'buzz' about the work Rich has done on other Carver amps - and was interested in getting my amp back to specs with service updates and the mods Rich does to get even more power out of this amp.

I opted for the 'standard' MKII mod package:
http://carvermk2.com/m10tmkII/m10tmkII.htm

Rich was easy to work with - responsive to emails and questions - and the price seemed reasonable compared to buying an new amp. So off it went for the service checkup, and mods.

I got the amp back just after 4 week with the standard MKII upgrade package with replaced capacitors and other parts and checked out to specs. Rich found an op amp that was troublesome and wanted to replace it, but was worried about the delay in order new parts - so he actually cannabalized another amp he owns for the part so that I could get mine back with no further delays. I thought that was a step above and beyond - and much appreciated so I could get my amp back in my setup.

Here's a shot of the new internal parts:


With the amp back in my rig, I decided it was worth some extra brass to upgrade the ICs, so I got some Audio Advisor(Quest) Black Mamba IIs to go from my AVR preouts to the Carver.

I've had the amp going every day for several hours a day for well over a week - movies, tv, lots of music - but not pushed too hard. This weekend I decided to put it thru some paces - CDs and LPs with dynamics and range - up to "Reference Level".

I recalibrated my AVR by running YPAO with the amp in the rig and the new cables to establish a fresh baseline of settings, then plopped down on the couch with the remote and the music playing.

Music Selections:
LPs
Allman Brothers: Win Lose or Draw
Steely Dan: Aja - Side II

CDs:
Peter Gabriel: So
Bryan Ferry: Bete Noire

Digital Cable:
Time Warner Cable: Chnl 929 Smooth Jazz

Results:


Ok - aside from the smiley - in 'technical terms'....
This amp is a BEAST! And dangerous.

With my RTiA3s and Epik Valor, the sonic qualities are more open, more spacious, more relaxed at reference volumes. This amp does not strain, sound stage stays open and does not 'collapse' when pushed. Bass response seems to be a bit tighter - probably due to the better dampening factor that is part of the MKII mod.

The danger is that with power rating of 400 watts per channel into 8 ohms, the response is so clean that it is now important to be wary of what the power rating of the speakers are.

My RTIA3s are 'only' rated at 125 watts per channel. The M-1.0t MKII has a dynamic rating of 670 watts, 450 watts at clipping :eek:

During my listening, I went up to -3db on my AVR after running YPAO, and the M1.0-t Leds were dancing and jumping up and down to the music - reaching just above their 50% mark - no where near approaching the Limiting Led mark.

The 'dangerous' part was that there were NO signs of straining, harshness, or collapsing of the sound stage - and the volume was deceptively loud because of the sonic clarity. I was tempted to go more - but was concerned I would push the RTiA3s beyond their power handling capacity - not out of concern of distortion or clipping from the amp - but that the power was just beyond their ability.

Clean....sonic....goodness.... not bad for the lowly regarded M-1.0t

RichP714

Erik Tracy wrote: »

Clean....sonic....goodness.... not bad for the lowly regarded M-1.0t

Hopefully the mk II is changing that impression (although we don't want ebay to get wind of it or the base unit prices will climb, they're a GREAT deal right now)

Ron Temple

Sounds like a great amp...now ...have fun Erik. Great job Rich.

RichP714

All my prices are at:

http://carvermk2.com

RichP714

Well, interest has been greater than expected; I've sold 14 so far, and don't have any left right now. As far as upgrades go I'm booked until mid-June on those.

It makes a great DIY project for those inclined (and I can help).

I hope to get a few more full units to upgrade, but will probably wait until I catch up on the upgrades.

RichP714

M-1.0t's usually sell on ebay at a lower price than, say M-1.5t or M-4.0t, which is a good thing if you're planning on modifying it anyway.

When they first came out, the M-1.0t had a pretty bad turn on/off thump. A fix came out later, but it gave the model a bad name.

It's also rated at 200W while the others are 380W. Lots of rumors as to why, but it was always a sleeper because of that (the stock amp'll do 365W)

Good luck! it's one of my favorite models, and has a glorious soundstage

RichP714

Lasareath wrote: »

Do you modify the M-4.0t ?

No, sorry. This whole thing started out as a personal project for my own gear.

The M-1.5t and M-4.0t have a different layout than the M-1.0t. The M-1.0t is easy to work on, with one main board and an open layout accessible from underneath.

On the M-1.5t and M-4.0t there are small, vertical boards. It's much harder to work on. I had brain surgery in 2002 that left me without the balance center in the brain (kind of like a compass that's now freely spinning).

As a result, even with my head vertical, the whole world is rushing past (if I close my eyes) and I have a permanent case of the 'bedspins'. If I tilt my head to the side, or upside down (as would be required to work on these models) I get a wave of nausea that puts me on the floor.

So it's not like I'm being snobbish, I just physically CAN't do it, sorry,
Rich

thsmith

Rich, it is amazing you are able to this work at all, good for you for making the best of it.

RichP714

New for 2009!


The Fulcrum power pivot

I mentioned around Christmas that I had a couple of ideas. With mk II upgrades booked through July my choices were to wait until August or multi-task. I wanted to see if this idea was workable, so I decided to pull out my prototype mk II and experiment a bit.

One problem with push-pull complimentary output stages is the emitter resistors allow a condition called common mode conduction. Near zero crossing, both polarities of the output stage are sourcing current through to the load. This allows greater heat levels, and disturbs the integrity of low level signals.

Phase I. The emitter resistors on the M-500(t) are a much higher value than they need to be. Reducing their value narrows the common mode conduction region

Phase II. strapping a transistor (and it's bias network) across both polarities of the output stage prevents both polarities from conducting at the same time.

I've had significant heat reduction, as well as increased fidelity to low level (delicate) passages. I don't have a spectrum analyzer, but I suspect the noise floor may have dropped as well.