Intro

[RichP714]

Hello everyone. I'm new to diyAudio, but have been a member over at CarverAudio for awhile now.

After a medical retirement, I'm finally able to start re-building my system again.

I'm running two pair of Klipsch Cronwall II's, and 8 modified Carver amps.

After experimenting for about nine months (I used to work for Carver repair back in the day) I came up with a stable, reliable performance boost for the Carver amps.

I'll get pics posted of my (hopefully nearing mid-fi?) system once I get the mess cleaned up (surround speakers still aren't installed, for example, and two amps are still on the floor)

In the meantime, for anyone interested in 'juiced' Carver amplification, check out:

carvermk2.com

[anatech]

Hi Rich,
Welcome to DiyAudio.

I am looking forward to see what you have been up to with these mods. Carver amps and power supplies were reasonably tightly engineered together, so large changes may have long term issues.

I always approach circuit changes very carefully and generally only make them to "fix" an engineering problem. I did work a little bit with Vic on some in warranty issues. Was he at all involved in your work?

-Chris

Edit: Hi Rich, after looking at your site, I do have some extreme concerns over what you are doing. Some of your mods (like output connectors) I can understand. I would use real binding posts though, not those things I see there. I guess yours are pretty though.

Normal servicing does include the factory change orders, and that makes for a solid service. Increasing the supply voltages is really not recommended from what I have read on your site. Also, matching diodes is not necessary. New ones will be very close and any good service replaces diodes as complete sets.

Possibly after reviewing your exact procedure I can comment further, but from what I have read so far I can't recommend anyone has their amps modified to your "type II" designation. My main objection is your increased supply voltages. The rest seems to be a combination of good servicing practices and the standard audio jewelery.

Finally, the supply capacitors in Carver amps normally do not last for 20 years, not even close. I'll bet they shows signs of failure after 10 years of normal use. More severe use can shorten that to 5 years, like those people who leave their gear on 24 / 7.

[RichP714]

Originally posted by anatech
.....I do have some extreme concerns over what you are doing. Some of your mods (like output connectors) I can understand. I would use real binding posts though, not those things I see there. I guess yours are pretty though....

Thanks for the welcome, you might not be aware, but you are somewhat reknowned over at Carveraudio.com amongst the elders'

.....Normal servicing does include the factory change orders, and that makes for a solid service. Increasing the supply voltages is really not recommended from what I have read on your site. Also, matching diodes is not necessary. New ones will be very close and any good service replaces diodes as complete sets.

I don't match diodes, just replace them. As long as they're functioning it's really not needed, but hey, they're cheap, and the in place ones have had a hard life. I'm retired, so it gives me something to do

Possibly after reviewing your exact procedure I can comment further, but from what I have read so far I can't recommend anyone has their amps modified to your "type II" designation. My main objection is your increased supply voltages. The rest seems to be a combination of good servicing practices and the standard audio jewelery.

Others have raised a similar objection re the rail boost. full details/parts list/etc are at M-500t mk II mod. My thinking was, as long as I didn't mess with the triac firing angle, the mag coil won't destroy itself from headon traffic. In other words, the spigot doesn't care how much water is in the tub. The voltage gain stage and PS caps are all replaced with higher voltage devices to handle the new swing.

Recently, I was lucky enough to grab Bob's ear....when he gets back from vacation he's going to advise on his thoughts. since I'm offering free repair for life (at parts cost) I don't want to be putting these units in harms way. First, do no harm

I HAVE modified my 8 Carver's to the mk II, and the dynamics are very tight. Runs about 10 degrees F hotter on the heatsinks.

.........Finally, the supply capacitors in Carver amps normally do not last for 20 years, not even close. I'll bet they shows signs of failure after 10 years of normal use. More severe use can shorten that to 5 years, like those people who leave their gear on 24 / 7.

Yes, the triac surge current can really put a hurt on the PS caps; the 20 yr I mentioned is most likely best case. Put her in an enclosed cabinet and foot to the floor and it'll be MUCH less.

[anatech]

Hi Rich,
I am very interested to see what you are doing. I have a rough idea from what you have on your site. I think it mentioned somewhere that you matched diodes, that's where that came from.

I'm retired as well. Too young and forcibly through a traffic accident (more like traffic stupidity). I find that I'm almost as busy as when I was running my own company years ago. Good to see you keeping busy, that's how you stay young.

I'll have another look on your link. There are a few places where the existing transistors and resistors where running too hot already. What I am worried about is the slow cook the boards already experience. Unfortunately the damage doesn't show until it's too late. Like not changing the oil in your car. Heat and high voltage are never a good mix, each on their own are problems enough! I can imagine you adding heat sinks to some transistors even stock, never mind with the higher voltages.

Recently, I was lucky enough to grab Bob's ear....when he gets back from vacation he's going to advise on his thoughts.

He's another person I've wanted to meet, I have never even talked to the man. I do hear he is supposed to be a straight shooter.

since I'm offering free repair for life (at parts cost)

I don't recommend doing that. Too much grey area. Good for sales though. Bryston pulled that silliness early on.

Thanks for the welcome, you might not be aware, but you are somewhat reknowned over at Carveraudio.com amongst the elders'

Now, how ever am I going to live up to that? Thank you though. I'm just a service guy with a big mouth!

-Chris

[RichP714]

Originally posted by anatech
[B]Hi Rich,
I am very interested to see what you are doing. I have a rough idea from what you have on your site. I think it mentioned somewhere that you matched diodes, that's where that came from.

I'll look at the site copy again; don't want to mis-lead anybody, I DO replace the existing diodes, but don't match them

.....I'm retired as well. Too young and forcibly through a traffic accident (more like traffic stupidity).

In my case it's also a forced retirement. In 2002 I had a seizure, and they discovered a left cerebellar AVM. After its ressection, I lost the entire cerebellum through a stroke, along with "a moderate amount of necrotic brain tissue". It's funny how reading something like that in your medical record has MUCH more impact than everyday hyperbole (I lost a TON of weight, etc). Had to learn to walk again, the whole thing.

.....I'll have another look on your link. There are a few places where the existing transistors and resistors where running too hot already. What I am worried about is the slow cook the boards already experience. Unfortunately the damage doesn't show until it's too late. Like not changing the oil in your car. Heat and high voltage are never a good mix, each on their own are problems enough! I can imagine you adding heat sinks to some transistors even stock, never mind with the higher voltages.

The TFM series was design much closer to the bone in that regard. The m-1.0t was the beginning (probably) of production engineers intervening to cut cost. The M-500t in many ways is over-designed. The pre-drivers, for example, 1.5A devices to supply base current to the output. By comparison, the M-1.0t drivers are 150ma devices (IIRC).

......He's another person I've wanted to meet, I have never even talked to the man. I do hear he is supposed to be a straight shooter.

I missed the opportunity to meet Bob at this year's Carverfest. All who attended had a similar opinion; very genuine guy.

Prior to the fest, he'd expressed interest in my mk II idea; I sent two along with a member. The member was also one of the coordinators of the fest, and barely had enough time to showcase his own system, though. Add to that, Bob brought along a pair of his new tube monoblocks, and my mk II's got trumped to the back burner (way back

.....I don't recommend doing that. Too much grey area. Good for sales though. Bryston pulled that silliness early on.

I know, it's not a very sound business plan, but I'm really not in this to make money. The wife has mandated that if I do this, I need to make SOMETHING for my time. An upgrade takes me approx 18 hrs and costs about $250. I'm charging $350, making a hundred, for 18 hrs (I could do better at McDonald's).

It's mostly about:
a) Giving me something to do, to feel useful
2) Getting better quality Carver gear out on the second hand market.

Some people have bought $300 'ebay' amps, and think that what they're hearing is all a Carver can do.

I don't expect that I'll be selling a whole lot of whole units, probably a few more 'upgrades' and mostly to a small group of close strangers

So as long as parts cost are paid, I don't mind fixing them for no labor.

[anatech]

Hi Rich,

I'll look at the site copy again; don't want to mis-lead anybody, I DO replace the existing diodes, but don't match them

Well, I don't have a web site. You are way ahead of me there! I wish I could tell you exactly where I saw that comment.

In 2002 I had a seizure, and they discovered a left cerebellar AVM.

You are not alone there. Many members here have disabilities that really restrict what they are able to do. Many much worse off than I am for sure. My accident damaged my brain stem and spinal column, plus lots of "soft tissue damage". Sounds nice, but the reality is more restrictive than broken bones. Today I think I forgot my morning meds and have spent the day in extreme pain, and got zero done. A "floor day". If I did take my meds, and things are getting worse ..... I don't know if I can handle it.

One thing about any type of brain injury is that it takes away the one thing you figured you would have as you grow older. Can't run - okay. Can't lift stuff or go out as normal to everyone else - okay. Can't think - well, that is definitely not okay. That is scary and brings an entire list of things that can be difficult to deal with. What you have gone through must have been very difficult for you and your family - and still is. It never goes away and you don't get a vacation from it.

I lost a TON of weight, etc

I gained 60 some-odd pounds.

The pre-drivers, for example, 1.5A devices to supply base current to the output.

150 mA predrivers are okay. The standard for driver transistors is a 1.5 A device in many amps. Since we didn't have a problem with driver failures or predriver failures, no problem. Now, heat there is a problem with Carver amps as the pre-drivers run off the full supply on all his amps I think. The larger case size will help with that. I would feel more comfortable with heat sink attached also.

The TFM series was design much closer to the bone in that regard. The m-1.0t was the beginning (probably) of production engineers intervening to cut cost.

As a younger tech I would have agreed with you more. Amplifier failures that we saw where generally traced back to serious abuse of the product. Very rarely did we see output failures, certainly below industry standards. This shift to reduce manufacturing costs did not adversely impact any owners. In fact, they got better as time went on. The move to different construction on the TFM series actually eliminated some failure areas after years of operation. Some parts were now running cooler. My favorite change - these amps were even easier to service. The M 1.5 series could be a real pain in the .... to service in the cap area. And that is where I've seen real trouble brewing.

Prior to the fest, he'd expressed interest in my mk II idea

Hey, I'm interested too. Anyones new take on an older idea can be very interesting. This is the place to explore these possibilities. There is a very large pool of engineering talent around here. BTW, Eva is someone to listen to regarding switching power supplies. When she talks, I listen very carefully.

The wife has mandated that if I do this, I need to make SOMETHING for my time.

I agree completely. However, don't sell yourself too short. You still have your test gear to replace or fix, parts to stock and the space. I do the same thing as you, and for the same reasons. Be fair to yourself when you price things out. It's no good for anyone if you can't support this and quit at some point. I'm just glad you are not overcharging. Another pet peeve. Seems the worse the "tech" is, the more they charge.

Some people have bought $300 'ebay' amps, and think that what they're hearing is all a Carver can do.

Honestly, don't feel badly at all about that. They do this with every single piece they buy. This is very true of equipment that has been with one owner since new. When that equipment is rebuilt, they have a new "whatever" and they hear it as new again. This is what I love to see, an owner falling in love with some equipment all over again. That is one thing that makes service worth while.

It's mostly about :
a) Giving me something to do, to feel useful

Yup, I hear you loud and clear! Same here, and that is one reason I post here as well.

2) Getting better quality Carver gear out on the second hand market.

I think you will find that you sell mostly to people who know you or were sent your way. On Eeekbay, people buy on price alone and you can not teach them otherwise. But go ahead and try. Just watch your stock levels carefully.

So as long as parts cost are paid, I don't mind fixing them for no labor.

No! You will end up losing money. That's just the way things turn out. You have to build in storage and capital that is tied up. Then there is your test equipment and repair of same. More things add up too. I often lose money as well, and I make sure I charge what is fair for labour fees.

Another way to look at this is that you are depressing the value of a service technician. I sold my shop because it was becoming impossible to be honest and raise a family on what the going service rates where. The only guys out there making money where the "problem" shops. Either that or they did industrial work or flat rate TV jobs. The guys who are still in the business make the same warranty money I did 10 years ago, and had for the previous 6 ~ 8 years. Rent and everything else has gone up and the public at large is "throw away". Your only business is warranty then, and now they want you to buy your service manuals!!!! This does not work and the honest guys out there need every dollar they can get to survive. You can charge less, but not a whole lot less. By doing so, you are hurting the others around you. Don't get me wrong, I'm not at all worried about me, I've got more than I can currently handle. I'm hoping to get better so that changes. It's the guys out there that I know and the industry as a whole I'm worried about.

It's already too darn hard to find good technicians in many areas.

Sorry, I ranted. That is another thing that needs to be addressed in the world.

-Chris

[RichP714]

i.....No! You will end up losing money. That's just the way things turn out. You have to build in storage and capital that is tied up. Then there is your test equipment and repair of same. More things add up too. I often lose money as well, and I make sure I charge what is fair for labour fees.

Another way to look at this is that you are depressing the value of a service technician.....

Yes, society today is WAY to 'throwaway/replace' and tech's don't get what they're worth.

I'm not trying to compete with an established business, there are a very few Carver capable shops in the US, and from what I've heard they do a wonderful job and really care about their customers uh, idiosyncracies i guess (meaning that 2 channel is fading to the iPod crowd).

As long as I come close to breaking even on this venture, I'll be happy.

As you mentioned, it's quite satisfying to return an amp to an owner and it's like he's rediscovering it. I've been lucky to have had that experience with these mk II's. It's also rewarding (although less frequent with home theater and mp3 so prevalent) to have a relatively new to audio individual really enjoy what you're doing. I've had that experience too.

[c2cthomas]

Hi Rich - and Welcome to diyAudio. Seems that you have been busy playing around with those electron thingies for a good while. I've only been fooling around with electronics for - errrr - well let's move on to the next subject.

The main thing is trying to keep the magic smoke from escaping the components it has been put into!

[RichP714]

Originally posted by c2cthomas
Hi Rich - and Welcome to diyAudio. Seems that you have been busy playing around with those electron thingies for a good while. I've only been fooling around with electronics for - errrr - well let's move on to the next subject.

The main thing is trying to keep the magic smoke from escaping the components it has been put into!

Thanks for the welcome, I've been doing electronics for a good while, first as a PMEL tech for the USAF, then doing mostly digital design work for the DoD, working XX ft underground on things flying XXX miles overhead.

I got cut short of 20 yrs by 2 months, due to a bit of brain surgery (i needed a hole in my head).

The magic smoke.......back in the day, we used to initiate newbies with a fishtank pump, a bit of plastic hose up into their gear, and a cigarette.......

[c2cthomas]

Hi Rich - Small world - I was a sillyvilian (US Civil Service) that worked in the depot PMEL shop at McClellan AFB near Sacramento CA. Moved over to Meteorological / NavAids depot repair section and played around there for - like 20 years. Air Force Brat - Navy Vet (missile fire control) and some other interesting attempts at silly things. Wound up with 28 years in all and then bailed when they shut the base down due to downsizing. Survived a cerebral hemorrhage in '06 and had a 5-way by-pass this past Feb. Still keeping busy tho - and planning on being around here for another 60 years or more!!!

"The magic smoke.......back in the day, we used to initiate newbies with a fishtank pump, a bit of plastic hose up into their gear, and a cigarette......." That was back in the days when you could still smoke indoors - need new tricks now. We liked to play "catch this" with a charged up capacitor.