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Advice Wanted for Updating Carver Gear

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I have recently purchased separates to replace my Carver 6250 receiver. I bought a CT-3 preamp, and a matching TFM-15CB amplifier. After getting it home, I found that the amplifie has intermittent issues in the right channel (not the preamp, as I tested it using my Nikko Alpha 130 amp). I went looking for an amplifier to replace it with while it was out being serviced, as the shop I use takes two to five months due to how busy they are. I found a gentleman who has a complete Carver system for sale for a very reasonable price. The system consists of a pair of M-200t power amps, a C-2 preamp, and a TX-11 tuner. All in really clean condition, and demoed to be working perfectly. So my question for all you Carverphiles is: Which is a better system? I'm liking the idea of using the dual power amps in bridge mode, as I am driving a pair of vintage Polk Audio SDA speakers that are really power-hungry. The specs for the TFM-15CB show it to be a much cleaner amp than the M-200t amps. I have the option of purchasing a second TFM-15CB from my repair guy, and he would give me a really good trade for the M-200t amps, preamp, and tuner. Just an FYI - 90% of my listening is with a vintage Technics turntable, listening to classic rock, jazz and some classical. So, what would you do?

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Keep what you have, buy the other Carver system as well. And for good measure, buy that second TFM-15CB. Thats how it goes in the beginning stages of OCCD.😁

 

Seriously, if finances permit, get the whole kit, everything.

You already have the right speakers. While your amp is in for service, look for another pair of those SDA speakers, maybe you'll score some Signature Series. There is nothing as magical as listening to a pair of mono-bridged Carvers driving a pair of SDA SRS2 Polk towers, with James Newton Howard & Friends on the turntable. 

 

And, btw, welcome to Carver Paradise. 

Edited by Butcher
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Thank you. I have been lurking on this site for over a year, and have been a Carver fan ever since I scored an MXR-150 at a yard sale ten years ago (guy wanted $40 for it - "powers up, but no sound". Brought it home and installed a pair of jumpers from the pre out to the main in, and voila - perfectly functioning receiver). It is in like-new condition, with the original wood end-pieces. I had it recapped about three years ago, and it tested out at 190 wpc at that time. Unfortunately, I passed on my vintage audio appreciation to my son, and I don't get to use that receiver any more. I bought the 6250 receiver to replace it, but it just doesn't have the oomph that the MXR has. That's why I bought the CT-3 and TFM-15CB. I could have just put my foot down and reclaimed the MXR, but I figured it was a good thing for my son to use it rather than the multi-channel junk that is out there now. He uses it with a pair of 1982 Polk Audio RTA-11t towers that we bought online for $50 and reconditioned.

Edited by ptrask
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You seem to have a good start, but I can recommend that you keep looking... 

These are the tuners you want: TX-11a or TX-11b. 

These are the preamps to bring you Bob Carver's magic: C-1, C-11, C-6, C-16, C-4000, 4000t, and the rare C-19. 

And the amps: M-200t, M-500, M-500t, M-0.5t, M-1.0t, M-2.0t, M-4.0t, TFM-42, TFM-45, TFM-55, TFM-75(rare and expensive), Silver Seven T, Silver Nine T.

Of the pre-tuners, only the CT-Seven seems to have the qualities, maybe a CT-17, if you can get a working one. 

Lastly, The Receivers, MXR-130/150, Receiver 900, Receiver 2000, 6200, 6250. Only the 6200 and 6250 do not have pre-out/amp-in jumpers for adding bigger amp(s). 

Polk speakers go very well with the Mag Coil Carver Amps. My first system was an MXR-150, M-500t with Polk Monitor 10's. I loved it!

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14 hours ago, ptrask said:

I'm liking the idea of using the dual power amps in bridge mode, as I am driving a pair of vintage Polk Audio SDA speakers that are really power-hungry.

The m200t is not going to be an option with the SDA unless you don't use the interconnect cable.

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Hi kve.   I've been offline quite a while - too long, but now back on, at least for the next few months.

 

Reminder to you and to all: the “Receiver 2000” is actually model MXR-180, even though it doesn't say so on it anywhere.  Great tuner, too – little need for a TX-anything with this unit in your system.

 

BTW, speaking of the CT-17, I have one for sale with remote and manual, working like new, with power supplies recapped.  Anybody interested, PM me.

 

RobertR

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Okay - I've opened up the TFM-15CB, and have diagnosed at least one problem with the amp. It is in dire need of recapping. The main caps are bulging, and I'm sure some or all of the smaller caps need replacement also. A few sellers on the bay have complete recap kits for around $35.00 for this amp. My question is: how difficult is it to recap a Carver amp? The recap kits come with complete instructions, and although I'm not an expert, I have decent soldering skills. I've recapped speaker crossovers in the past, but those boards are a lot more basic than the boards in the Carver. What do you all think?

 

Also, if I decide to do this, will the caps from a kit like this be of decent quality? I don't want to spend the time recapping with lower-end capacitors. I've already got replacement LEDs for the meter lights, as I can't see pulling it apart and not doing that upgrade. I see that many people selling "modded" TFM-15 amps mention the LED upgrades, and also "painted needles". What do they mean by that?

 

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There is no way of knowing where a kit was sourced. If I had the skills to work on my gear, I would avoid a kit and track down parts from Mouser, Digikey, or Parts Express myself. Some have mentioned BOMs, but I don't recall one for a TFM-15c.

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10 hours ago, ptrask said:

Okay - I've opened up the TFM-15CB, and have diagnosed at least one problem with the amp. It is in dire need of recapping. The main caps are bulging, and I'm sure some or all of the smaller caps need replacement also. A few sellers on the bay have complete recap kits for around $35.00 for this amp. My question is: how difficult is it to recap a Carver amp? The recap kits come with complete instructions, and although I'm not an expert, I have decent soldering skills. I've recapped speaker crossovers in the past, but those boards are a lot more basic than the boards in the Carver. What do you all think?

 

The interiors of Carver amps can seem like a nightmare but if you have those decent skills I wouldn't worry much about it. Take photos and notes, and pull the main board out if you can instead of working on it in place. You probably know what to do pull your bad electrolytics, insert the new ones with a bit of tension spread on the leads, flip the board over and lay it component-side down on a  large terry towel. The weight of the board will make sure everything sits peacefully, the towel keeps it from sliding around as you work on it. It also adds a bit of fun risk as you try not to set the towel on fire. But thats just how I am. YMMV. 

 

Quote

 

Also, if I decide to do this, will the caps from a kit like this be of decent quality? I don't want to spend the time recapping with lower-end capacitors. I've already got replacement LEDs for the meter lights, as I can't see pulling it apart and not doing that upgrade. I see that many people selling "modded" TFM-15 amps mention the LED upgrades, and also "painted needles". What do they mean by that?

 

 

Thats simply people trying to make the amps "theirs". Changing lights, needles, faces, etc. 

 

9 hours ago, Sk1Bum said:

There is no way of knowing where a kit was sourced. If I had the skills to work on my gear, I would avoid a kit and track down parts from Mouser, Digikey, or Parts Express myself. Some have mentioned BOMs, but I don't recall one for a TFM-15c.

 

Bum speaks the truth. The person you refer to offers a solid kit, but he's using middle of the lane parts, and he's making a profit on that. (Nothing wrong with the profit part of it, I'm simply pointing out that you're paying for him to gather the parts up as well as the parts themselves, so his margin at the retail you're paying indicates he's selling you parts that are cheap enough for him to make a decent cut. You could spend the same money on better parts if you do the source work.) His kit is good for a person who wants to refurbish to average spec, but you're in there doing the labor, so source better parts and put them in. 

What I'd really like to see here is a discussion of mod parts and how one should know one is getting a better part. I've grown up around machinery, where you would know for a fact that higher tolerance is generally better. In audio however, I've seen plenty of people offering 1 percent carbon resistors to replace 5 percent sand cast resistors, but I've also known plenty of people to warn others against replacing those parts without a plan, lest one affect the final sound and not in a good way.

I tried replacing some ICs on a preamp a few years ago. At first I looked at surplus replacement parts but I was told that there were newer production similar parts that would be better. Then I was told that I shouldn't do that because the original preamp was designed around those old parts and "upgrading" would be detrimental. 

In the car audio business, a well-known repair instructor basically disowned me for suggesting that car amps could be modified for better sound. 

So how would you know that a 1 percent would work and sound better? Where would it / wouldn't it matter? Where would a bigger capacitor help vs hurt? Where would input/driver/output transistor replacements help/hurt/not-do-a-damned-thing?

 

Enquiring minds, and all that bother...

Edited by Butcher
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1 hour ago, Butcher said:

What I'd really like to see here is a discussion of mod parts and how one should know one is getting a better part. I've grown up around machinery, where you would know for a fact that higher tolerance is generally better. In audio however, I've seen plenty of people offering 1 percent carbon resistors to replace 5 percent sand cast resistors, but I've also known plenty of people to warn others against replacing those parts without a plan, lest one affect the final sound and not in a good way.

 

These discussions are literally all over the site my friend. :D

 

Anyway, this is a very sensitive topic to get into. I would suggest avoiding talking about things like 'capacitor sound' and 'resistor sound quality' because it gets nowhere. Many people are absolutely convinced they can hear different kinds of capacitors even though virtually nothing can be measured to distinguish them, and if there is a difference, it's so minute it's negligible in audio. All over a component that is nothing more than two plates of metal very close together.

 

On the other hand - just recently the use of 1% metal film resistors in a pre amp signal path was vehemently down played as a 'waste', even though most pre amp designs include such components in their high impedance and gain stages. Even though 1% metal resistors out perform carbon composite on nearly every spec. Even though they look cooler. Even though they're relatively cheap. Even though they're easy for a DIYer to replace. Even though their overall contribution in the mod is better than stock when measured.

 

So...I hope you understand what you're in for...

 

Thick skin required.

 

However, there are basically three ways to approach a 'mod'.

 

Tweaker - tweakers believe changing parts will always make something sound better. They seek out expensive, often trendy components that almost no manufacturer uses because of their cost. However, the cost often justifies the choice. They often don't know anything about the circuit design...it's the capacitor that makes things sound better or worse. But as long as the workmanship is GOOD, there's nothing inherently wrong with this sort of modding. It's a cup of tea for some and not others for sure. It's certainly compelling, but the science (that is, measurements) is still out as to whether such practices can overcome decades of dedication to scientific principals that result in topological designs that overcome sensitivity to individual component performance. In some cases, as I've personally witnessed (and done), they change out components that have no impact on the audio signal whatsoever. But hey, more gold colored components is always better. :D

 

Technician - They understand enough to know what works better by experience, usually because the manufacture used cheap parts to meet production goals. There are some obvious improvements, such as capacitor life and resistor tolerances and power handling that can make circuits works much better. A practical approach.

 

Engineer - by understanding how a circuit works, and perhaps why it may not be performing as well as it could, an engineer will change out/add/subtract components to meet a design goal. By taking careful measurements and comparing results, a mod is the result of actual tests to improve performance in some way. Whether these changes 'sound good' is up to the listener, of course. An engineer can do all of the above, and it will have more weight for acceptance because...well...they're an engineer!

 

I hope this helps us all get along. :D

 

 

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1 hour ago, Nahash5150 said:

An engineer can do all of the above, and it will have more weight for acceptance because...well...they're an engineer!

 

I hope this helps us all get along. :D

 

I think you meant should have?

 

I often get tangled in a discussion with one tweaker giving advice to another; if that advice is incorrect, or an oversimplification, I often try to steer the advice into more accurate territory, and I'm often either disregarded or rewarded with punitive remarks

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24 minutes ago, RichP714 said:

I think you meant should have?

 

Indeed it should!

 

31 minutes ago, RichP714 said:

I often get tangled in a discussion with one tweaker giving advice to another; if that advice is incorrect, or an oversimplification, I often try to steer the advice into more accurate territory, and I'm often either disregarded or rewarded with punitive remarks

 

It could be argued - what has more value in the marketplace of ideas - knowledge or persuasion? People will embrace others that agree with them, and will dislike those that don't. It's just the way it is.

 

And I certainly understand your sentiment. I don't comprehend the social games that people play to influence one another, but I've been told often that 'it's not what you say but the way you say it'. In other words, if you have to disagree, serve the dessert first. I think...

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37 minutes ago, Nahash5150 said:

And I certainly understand your sentiment. I don't comprehend the social games that people play to influence one another, but I've been told often that 'it's not what you say but the way you say it'. In other words, if you have to disagree, serve the dessert first. I think...

 

Yes, when BillD was posting here, we'd often say the same thing, but he'd get thanked and I'd get derided; we used to laugh about that.

 

Nowadays, I am conscious of this, and attempt to NOT include any personal accusations or salacious language, I try to be as factual as possible when trying to illuminate any particular topic, and try to include references rather than personal assertions.  I don't recall a time when I've purposefully tried to piss someone off, yet it happens, as you said.

Edited by RichP714
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58 minutes ago, RichP714 said:

 

Yes, when BillD was posting here, we'd often say the same thing, but he'd get thanked and I'd get derided; we used to laugh about that.

 

Nowadays, I am conscious of this, and attempt to NOT include any personal accusations or salacious language, I try to be as factual as possible when trying to illuminate any particular topic, and try to include references rather than personal assertions.  I don't recall a time when I've purposefully tried to piss someone off, yet it happens, as you said.

 

Bill was also well known for doing favors...I'm sure this helped his reception significantly.

 

Image result for bill clinton thumbs up

 

Savy?

 

So someone joins the forum and they want a service manual.

 

Rich - posts a link to the Manuals Database

Bill - PM's the newbie and attaches the manual file to his post and offers to help him fix it.

 

Both are helpful - yet one knows how to play the heart strings that make people feel good and important. The other is a teacher that encourages others to learn (starting with how to use the website) and develop a stronger mind.

 

That's all it is.

 

 

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11 hours ago, Nahash5150 said:

 

These discussions are literally all over the site my friend. :D

 

Yeah, its that whole "sort through it all for a few weeks" thing that gets me, though. Theres a few hundred pages of info here, once you condense out all the hugs 'n arguments and all. :D

 

 

11 hours ago, Nahash5150 said:

 

Anyway, this is a very sensitive topic to get into. I would suggest avoiding talking about things like 'capacitor sound' and 'resistor sound quality' because it gets nowhere. Many people are absolutely convinced they can hear different kinds of capacitors even though virtually nothing can be measured to distinguish them, and if there is a difference, it's so minute it's negligible in audio. All over a component that is nothing more than two plates of metal very close together.

 

Agreed there. Much of it seems like alchemy to me. I can hear the difference between zip cord and heavy gauge wire - many people can -  but I can't hear the difference between heavy gauge wire and oxygen isolated triple aught braided large mouth bass fur. Maybe someone out there can, but it isn't me. (Then again, there was at least one gent I read about a few decades back who could look at a given LP and based on his recognition of the groove pattern he could tell you what music was on it. He could tell you the composer, the movement, etc. He was getting to the point to where he could tell you where the performance occurred and what orchestra played it. Bloody brilliant, and it shows you that there are some very odd superpowers out there.)

As for the esoteric resistor and capacitor wizard you speak of, that sounds like a certain geezer in the Hafler world...

 

11 hours ago, Nahash5150 said:

On the other hand - just recently the use of 1% metal film resistors in a pre amp signal path was vehemently down played as a 'waste', even though most pre amp designs include such components in their high impedance and gain stages. Even though 1% metal resistors out perform carbon composite on nearly every spec. Even though they look cooler. Even though they're relatively cheap. Even though they're easy for a DIYer to replace. Even though their overall contribution in the mod is better than stock when measured.

 

See, that's the thing I speak of: how does one know? Some of us just want to get on the horn and order a pile of replacement parts and clean up the sound where it's possible. I have a rudimentary lab here, with a scope and meter, but I don't have things like IM/THD measurement gear, and I wouldn't know how to use it if I did.


I sit (not stand, I'm tired) in amazement when I read about people like Bob Carver or Nelson Pass. Carver because he loves playing component games to make things do what people say isn't possible. Pass because he wakes up every day and says "how can I do more, with a simpler circuit". If those two guys ever put their efforts together - and it didn't cause a cataclysm - they would rule the audio world. 

 

Like I said, bloody brilliant. 

 

 

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13 hours ago, Butcher said:

 

Yeah, its that whole "sort through it all for a few weeks" thing that gets me, though.

 

A week is less time, and certainly less expense, than the accompanying preparation (Masters in EE) would cost; by comparison this place is a bargain

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Back more on topic, I would add that the amp in question is a pretty easy recap job - not too many electrolytics in the TFM-15 - so if you want to get into this game it's a good model to cut your teeth on.   Be aware that there is one cap in each channel that is 'non-polarized' - be sure to replace it with that type.   All the others must be installed with the correct polarity, or you're screwed,  just as with a car battery.

 

I'd put the two big filter caps in first; they are needed for sure.  Then try her out.   Then maybe do a few more,  mirroring in the second channel what you replace in the first, and try her again.  Then some more, and test, etc.  This way, if it doesn't work right at some point, you have a much smaller area to go back and recheck.  If the intermittent problem persists, you will have to deal with that, but you won't have wasted any time, because she needed a recap anyhow.

 

RobertR

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2 hours ago, RobertR said:

Back more on topic, I would add that the amp in question is a pretty easy recap job - not too many electrolytics in the TFM-15 - so if you want to get into this game it's a good model to cut your teeth on.   Be aware that there is one cap in each channel that is 'non-polarized' - be sure to replace it with that type.   All the others must be installed with the correct polarity, or you're screwed,  just as with a car battery.

 

I'd put the two big filter caps in first; they are needed for sure.  Then try her out.   Then maybe do a few more,  mirroring in the second channel what you replace in the first, and try her again.  Then some more, and test, etc.  This way, if it doesn't work right at some point, you have a much smaller area to go back and recheck.  If the intermittent problem persists, you will have to deal with that, but you won't have wasted any time, because she needed a recap anyhow.

 

RobertR

Thanks. This is the type of information I was looking for! Now I just need to clear off space on my workbench, and I can get started.

Edited by ptrask
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 Get your hands dirty. Order some reasonable parts and have some fun. The more you dig around and try stuff the more you will learn. All of us make mistakes so who cares about that. Fixing your own screw ups is a great way to learn. Just don’t electrocute yourself in the doing.

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