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Amplifier Building vs old and used?

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  • #31
    Re: Amplifier Building vs old and used?

    I've done this math many times....if it's for FUN or a super-specific purpose go ahead and build the amp. If the idea is to get a high quality amp for a good cost, or even learning about how they work a used amp can be an awfully good value. I just got a 150WPC into 8 ohm, Crown amp for $50 because one channel didn't work. The root cause was a bad connection in a phono jack. $3.00 fix and I got a ~50lb beast of an amp for $53 and an hour or two of work. It has a 1kVA transformer in it and I couldn't buy one for under $100-$150...so....a steal.

    Scott
    DIYRM-A Thread, a 60 page speaker design guide
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    Direct link to DIYRM-A/B Updated PDF

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    • #32
      Re: Amplifier Building vs old and used?

      Yup!

      http://www.antekinc.com/1000va/
      Craig

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      • #33
        Re: Amplifier Building vs old and used?

        Originally posted by jason171717 View Post
        Thanks for the help. Can you even get emotiva for $400?

        I still have to do some more research to find what the price range is but i am pretty sure, from what i have seen, this is a good deal.

        I got my brand-new Emotiva UPA-2 for $399. Amazing build quality and SQ, super robust, loafs running my Statement Monitors' 4-ohm load to ridiculous levels. The used Adcom or Hafler would be something I'd consider, terrific amps. We sold Adcom and they were super-reliable with any hard-to-drive 4-ohm speaker. Guys on the Emotiva forum have gear for sale...I was thinking about selling my USP-1 pre-amp (no longer produced) to fund an XSP-1 pre-amp purchase. I've heard they were coming out with a new 2-channel pre-amp like the USP-1 and in that price-range, but so far nothing. The XSP-1 is the only one they have right now and it's pricey. The UPA-2 is so capable, I'll be keeping that. Let us know what you get and what you think.


        John A.
        "Children play with b-a-l-l-s and sticks, men race, and real men race motorcycles"-John Surtees
        Emotiva UPA-2, USP-1, ERC-1 CD
        Yamaha KX-390 HX-Pro
        Pioneer TX-9500 II
        Yamaha YP-211 w/Grado GF3E+
        Statement Monitors
        Vintage system: Yamaha CR-420, Technics SL-PG100, Pioneer CT-F8282, Akai X-1800, Morel(T)/Vifa(W) DIY 2-way in .5 ft3
        Photos: http://custom.smugmug.com/Electronic...#4114714_cGTBx
        Blogs: http://techtalk.parts-express.com/blog.php?u=2003

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        • #34
          Re: Amplifier Building vs old and used?

          I have 2 original NAD 3020s, an original Bryston 2B and a Bryston 2B LP pro. In my experience, electrolytic caps stand a good chance of going south and needing replacement after ~ 25 years. I recapped the power supply in both Brystons and one NAD is in now need. Symptom is low level hum. So its risky to buy too old an amp.

          I also have an LM3886 amp, from a chinese ebay suppler. Build quality was good but I prefer the sound of the old NADs and the Brystons. I played the amp at a DIY get together and no one was too thrilled with it.

          I have heard an LJM amp and it smoked all the previously mentioned amps. It was very clean and powerful. Just be careful if paring with bright speakers, it may be a bit too hot sounding.
          I've heard great things from reliable sources about the ClassDaudio amps (similar design to the LJM but more expensive; however more turn key and better support)

          Comment


          • #35
            Re: Amplifier Building vs old and used?

            Behringer A500 , buy two brand new with free shipping for $400
            donc

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            • #36
              Re: Amplifier Building vs old and used?

              Originally posted by DDF View Post
              I have 2 original NAD 3020s, an original Bryston 2B and a Bryston 2B LP pro. In my experience, electrolytic caps stand a good chance of going south and needing replacement after ~ 25 years. I recapped the power supply in both Brystons and one NAD is in now need. Symptom is low level hum. So its risky to buy too old an amp.

              I also have an LM3886 amp, from a chinese ebay suppler. Build quality was good but I prefer the sound of the old NADs and the Brystons. I played the amp at a DIY get together and no one was too thrilled with it.

              I have heard an LJM amp and it smoked all the previously mentioned amps. It was very clean and powerful. Just be careful if paring with bright speakers, it may be a bit too hot sounding.
              I've heard great things from reliable sources about the ClassDaudio amps (similar design to the LJM but more expensive; however more turn key and better support)
              Yeah..I've re-capped quite a few. If you're willing to put in a little hobby time that is fun for you it's not that bad of a job...at this point I've re-capped: McIntosh, Krell, Classe, Crown, BGW, SAE. Some are easier than others...the McIntosh PCBs were very high quality and easy to resolder...the BGW amp....less so.

              Scott
              DIYRM-A Thread, a 60 page speaker design guide
              Tumblr
              Direct link to DIYRM-A/B Updated PDF

              Comment


              • #37
                Re: Amplifier Building vs old and used?

                I should also add that I look at the schematics for every piece of vintage amplification before I buy...if they include the awful STK power pack output stages I avoid them like the plague....there are some otherwise nice units with VU meters, reasonable transformer....that are rendered useless by these silly parts.
                DIYRM-A Thread, a 60 page speaker design guide
                Tumblr
                Direct link to DIYRM-A/B Updated PDF

                Comment


                • #38
                  Re: Amplifier Building vs old and used?

                  Originally posted by SpeakerScott View Post
                  I've done this math many times....if it's for FUN or a super-specific purpose go ahead and build the amp. If the idea is to get a high quality amp for a good cost, or even learning about how they work a used amp can be an awfully good value. I just got a 150WPC into 8 ohm, Crown amp for $50 because one channel didn't work. The root cause was a bad connection in a phono jack. $3.00 fix and I got a ~50lb beast of an amp for $53 and an hour or two of work. It has a 1kVA transformer in it and I couldn't buy one for under $100-$150...so....a steal.

                  Scott
                  That is a steal! I hope i can find some like that :p Is there any purpose modifying the older amps to increase power/ or sound quality?

                  Comment


                  • #39
                    Re: Amplifier Building vs old and used?

                    Originally posted by johnastockman View Post
                    I got my brand-new Emotiva UPA-2 for $399. Amazing build quality and SQ, super robust, loafs running my Statement Monitors' 4-ohm load to ridiculous levels. The used Adcom or Hafler would be something I'd consider, terrific amps. We sold Adcom and they were super-reliable with any hard-to-drive 4-ohm speaker. Guys on the Emotiva forum have gear for sale...I was thinking about selling my USP-1 pre-amp (no longer produced) to fund an XSP-1 pre-amp purchase. I've heard they were coming out with a new 2-channel pre-amp like the USP-1 and in that price-range, but so far nothing. The XSP-1 is the only one they have right now and it's pricey. The UPA-2 is so capable, I'll be keeping that. Let us know what you get and what you think.


                    John A.
                    I will have to keep a look out for the haflers and adcoms, i found a couple of haflers but didnt get there fast enough, good feeling they are gone already !I will look for the upa-2 so far a lot of the reviews i have read have been raving about the amp. At $400 it sure has the looks ;) I will be sure to let you know what i go with, i am in contact with the Rotel seller that i posted in the original post, the power,pre and tuner, good full package even if i do go with something different in the end. He has so Bower Wilkins that we will be testing that amp on so sound testing will be done before purchase. It wont help me much because i do need to test the amp A-B'ing between my amps on my speakers, but atleast i will get a sample

                    Comment


                    • #40
                      Re: Amplifier Building vs old and used?

                      Originally posted by DDF View Post
                      I have 2 original NAD 3020s, an original Bryston 2B and a Bryston 2B LP pro. In my experience, electrolytic caps stand a good chance of going south and needing replacement after ~ 25 years. I recapped the power supply in both Brystons and one NAD is in now need. Symptom is low level hum. So its risky to buy too old an amp.

                      I also have an LM3886 amp, from a chinese ebay suppler. Build quality was good but I prefer the sound of the old NADs and the Brystons. I played the amp at a DIY get together and no one was too thrilled with it.

                      I have heard an LJM amp and it smoked all the previously mentioned amps. It was very clean and powerful. Just be careful if paring with bright speakers, it may be a bit too hot sounding.
                      I've heard great things from reliable sources about the ClassDaudio amps (similar design to the LJM but more expensive; however more turn key and better support)
                      Do you agree with he train of though that two smaller toroidal transformers are better than one larger one? I will try to recap the rotel if i am able to get the front plate off without too much fuss if not the vintage electronics guy i know will fix up the whole thing; caps, broken lights, and any other need of fixing items for $75. So if worse comes toworse i know where i will tkae it.

                      "and no one was too thrilled with i" could that be because of the lack of headroom?

                      "but more expensive" i stopped reading temporarily ;) on a more serious note, have you ever actually heard the amps in question or just heard from your sources?

                      Comment


                      • #41
                        Re: Amplifier Building vs old and used?

                        Originally posted by donc View Post
                        Behringer A500 , buy two brand new with free shipping for $400
                        donc
                        Interesting that you bring up the a500 i have been wondering about that amp for a while, i was a touch turned off by the small weight of the amp compared to other more expensive (in there day) amps that are in the same price range. The good news i that i will be able to get a listen of a friends, he is planning on bringing it over for me to try, i will see how it sounds compared to my other amps.

                        Comment


                        • #42
                          Re: Amplifier Building vs old and used?

                          Some folks really like the Sure amps. You can even get a volume control for about $5. You can also find an amp and power supply from this link.
                          One thing to watch with these amps is the power rating. An amp might be listed as 500 watts/channel. However, that might be at 3 ohms and 10% distortion. If so, the wattage is going to be reduced with higher impedance

                          http://store.sure-electronics.com/au...mplifier-board.
                          "We're speaker geeks, not speaker nerds. Nerds make money!" Marty H
                          Bismarck, North Dakota
                          My Current System: Jolida SJ502A, Squeezebox Touch, and Carmody Sunflowers
                          My Garage System:Marantz 2238B and Nano-Neos

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                          • #43
                            Re: Amplifier Building vs old and used?

                            Originally posted by SpeakerScott View Post
                            I should also add that I look at the schematics for every piece of vintage amplification before I buy...if they include the awful STK power pack output stages I avoid them like the plague....there are some otherwise nice units with VU meters, reasonable transformer....that are rendered useless by these silly parts.
                            https://www.google.ca/search?q=STK+p...w=1920&bih=979 This chip?


                            "that are rendered useless by these silly parts" what does this part do to ruin them?

                            Comment


                            • #44
                              Re: Amplifier Building vs old and used?

                              I guess it is a good thing that i went with a lower impedance and higher efficiency for my DIY mains, eh? If the specs are listed you can tell what the rating was at correct? I know a lot of AVR are listed at 1 channel driven and 10% distortion at lower impedance's at an easy to reproduce 1khzonly

                              Comment


                              • #45
                                Re: Amplifier Building vs old and used?

                                Originally posted by jason171717 View Post
                                https://www.google.ca/search?q=STK+p...w=1920&bih=979 This chip?


                                "that are rendered useless by these silly parts" what does this part do to ruin them?
                                Those early monolithic amplifiers have poor reliability and are difficult to find replacements. Basically, it's a great unit while it works, then when it dies you have to completely redo the output amplifier stage if you can't find the appropriate monolithic amp parts. If you do find them they are typically expensive (compared to transistors) and one slip up in repair means you blow that one too. The chassis has some inherent value, so if you can get a nice all metal one with reasonable heatsinks and transformers for $5-$20 it can be a good deal...but you should know that going in.
                                DIYRM-A Thread, a 60 page speaker design guide
                                Tumblr
                                Direct link to DIYRM-A/B Updated PDF

                                Comment

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