philly0116 Posted June 28, 2014 Share Posted June 28, 2014 About 6 months ago I got a good deal on a Carver M1.5t. Based on a majority of reviews I read I bought it. Initially I was very pleased with it and thought it sounded great. At this point though, I am kind of tired of the sound. When I crank the volume I find the amp losing low end considerably. There's no problem with the amp operationally. I found myself going back to my hafler DH-220 in favor of the Carver!! Anyone else have any experience with the Carver amps? Similar or otherwise? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Chris A Posted June 28, 2014 Share Posted June 28, 2014 (edited) One of the tricks that Bob Carver uses in his vintage amplifier designs was that he uses the power company transformer outside of your dwelling as part of the amplifier "system". This means that you need a really good dwelling electrical system feeding this amplifier in order to keep it supplied properly. See http://twit.cachefly.net/video/htg/htg0029/htg0029_h264b_864x480_500.mp4 for a discussion by him personally. I learned this first hand when I first used my M1.5t in an apartment complex (driving Magnepan MG-IIIa's) in the early 1980s. When I eventually moved to a new house, the issues with my amplifier losing drive under sustained high-SPL conditions basically disappeared when driving the Magneplanars, which were extremely power-hungry. I don't recommend using a power conditioner between this amplifier and the house power supply because of this. If you are running Klipsch loudspeakers, you probably don't need that kind of power (400 W/channel sustained) to drive them. What are you driving, if I might ask? Chris Edited June 28, 2014 by Chris A Quote Link to comment Share on other sites More sharing options...
philly0116 Posted June 28, 2014 Author Share Posted June 28, 2014 I'm driving RF-7's with it. Extremely efficient, so no, your right about not needing the power! Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
philly0116 Posted June 28, 2014 Author Share Posted June 28, 2014 Wow. I just watched some of that video. That's very interesting. I personally do not like that design! I don't like the idea of depending on a power transformer all my neighbors are also depending on. Power transformers don't carry the same characteristics so that adds a variable. I don't personally care if an amp weighs 200lbs or 10lbs, I want it to perform on its own without having to rely on an outside source. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Chris A Posted June 28, 2014 Share Posted June 28, 2014 (edited) It's really about economics of higher power amplifiers being so expensive. Actually, I thought that Carver was really ingenious in dealing with a severe design problem - namely avoiding higher power-supply transformer costs. Remember that there are a lot of "audiophile" loudspeakers of that vintage that were and largely still possess extremely low efficiency, usually indirectly described in terms of sensitivity which in the case of the Magneplanars was like 83 dB at 1W-m on axis. Some other loudspeakers were even lower--such as electrostatic designs. I recall that when when the M1.5t was driving the MG-IIIa's flat out, it really wasn't that loud. I didn't have complaints about the Carver amplifier - but a lot more on dipole planar loudspeakers that don't sound very good off-axis, even as little as 2-3 inches off-axis. One of the more interesting audio articles was written by PWK on the subject of loudspeaker efficiency vs. distortion, i.e., modulation distortion--the most audibly objectionable type. He proposed an empirical relationship based on measurements to state that the higher the loudspeaker's efficiency, the lower its distortion. I've found that there are a lot of vested interests in the industry that don't want that statement to be true. Chris Edited June 30, 2014 by Chris A Quote Link to comment Share on other sites More sharing options...
philly0116 Posted June 28, 2014 Author Share Posted June 28, 2014 No one can argue he is genius! Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
absolve2525 Posted July 1, 2014 Share Posted July 1, 2014 My 1.5t kicks *** with my Infinity planar hybrid speakers. I mean, the power is seemingly limitless. There is a recommended update circuit board containing new caps that is sold on Ebay. Perhaps yours needs the update. I have also found that preamp makes a considerable difference. Which preamp are you using? I sold the Adcom GFA555II and kept the Carver. I agree though, you don't need nearly that much power for Klipsch. Quote Link to comment Share on other sites More sharing options...
djk Posted July 1, 2014 Share Posted July 1, 2014 (edited) A 1.5T is at least 35 years old, replace the caps. Replace the rectifiers on the two lower supply tiers too, use 6A (3A is stock). The to LED on the display is marked 'headroom exhausted', that means you are 14dB into limiting when it comes on. "One of the tricks that Bob Carver uses in his vintage amplifier designs was that he uses the power company transformer outside of your dwelling as part of the amplifier "system". " Frequently repeated BS, not accurate. All power amplifiers use the power company transformer on the pole as part of the system. (unless you're using a battery powered T-amp). All Bob did was put a light-dimmer control on the power transformer, that's it. The conduction angle of the dimmer is increased when the amplifier is driven harder. If you disconnect the peak limiter a M1.5T will slam like a ton of bricks in the bass when you clip it (as will any other amp). The early PM1.5's for PA use had this feature on the front panel, they had the same amplifier modules, and the same power supply. They also made a 2Ω version called a PM1.5L A 1.5 is hard to test with both channels driven full tilt, it will blow a 20A breaker right now. On typical program material they will clip at 600W at 8Ω, and can drive a 70V line direct. Edited July 1, 2014 by djk Quote Link to comment Share on other sites More sharing options...
Thedogster1 Posted June 14, 2020 Share Posted June 14, 2020 (edited) I was wondering if anyone would have any schematics for a 1.5t mine isn't working and I have a guy who can fix it as long as he has the schematics for the amp...he tried to fix it without one and spent 6 hours on it and had no luck...he said it's too complicated without the schematics....he doesn't know where to start.so if anyone has any idea where I could acquire them I would greatly appreciate it...carver is my favourite....I even have a carver car amp which sounds awesome...and just acquired a couple of carver subs recently ,will be picking them up tomorrow.oh btw it's a m1.5t schematic I'm looking for.... Edited June 14, 2020 by Thedogster1 Important detail left out Quote Link to comment Share on other sites More sharing options...
96lt1ss Posted January 4, 2021 Share Posted January 4, 2021 On 6/14/2020 at 2:03 AM, Thedogster1 said: I was wondering if anyone would have any schematics for a 1.5t mine isn't working and I have a guy who can fix it as long as he has the schematics for the amp...he tried to fix it without one and spent 6 hours on it and had no luck...he said it's too complicated without the schematics....he doesn't know where to start.so if anyone has any idea where I could acquire them I would greatly appreciate it...carver is my favourite....I even have a carver car amp which sounds awesome...and just acquired a couple of carver subs recently ,will be picking them up tomorrow.oh btw it's a m1.5t schematic I'm looking for.... https://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Carver-M1.5-Service-Manual.pdf 1 Quote Link to comment Share on other sites More sharing options...
Marcm Posted December 5, 2021 Share Posted December 5, 2021 On 1/4/2021 at 4:48 PM, 96lt1ss said: https://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Carver-M1.5-Service-Manual.pdf I sent my M500t to Greg Garska in Washington to be refurbished & have the mkll upgrade. I have had this amp since the 80s that I bought new and it is a better amp today. He charges a fair price and is great to work with Quote Link to comment Share on other sites More sharing options...
OldCrow Posted October 8, 2023 Share Posted October 8, 2023 No one's posted for a couple years, but here's my two cents. I bought a 1.5 in '85 and it recently conked out. It was a beast driving Polk Audio SDA 1s and later the big SRSs. I had three concerns - a slight hum through the speakers, a speaker thump at turn off, and NO power switch! I sent it to Nelion Audio, MI for reconditioning and the MKII upgrade which included a power switch. It's better than ever! Detail and texture that I haven't heard before, just spectacular. There's more power, but that was never really an issue. Added new binding posts, an IEC socket, AND a power switch! No hum, no thump, it's a ghost. Serving in the military practically requires owning a great stereo. In my 24 years USAF, I bet I heard close to 100 hi-end systems. Carver owners were almost always happy campers. Bob's a genius and not only misunderstood, but pretty much incomprehensible to us regular types. There's mentioned in a previous post of a technician who couldn't understand what was happening inside and said it's too complicated. No kidding! Specs are all well and fine, but who cares when it sounds magnificent? 1 Quote Link to comment Share on other sites More sharing options...
the real Duke Spinner Posted October 11, 2023 Share Posted October 11, 2023 I am sure that I have posted on Carver beforeI have enjoyed many examples of this equipmentincouding my Flame Liberal 490 Not the ultimate stuff in high resolution, but pretty good in it's time. 1980s It was built to a price point, and may be difficult to have repaired these days Quote Link to comment Share on other sites More sharing options...
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