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  • jason171717
    replied
    Re: Amplifier Building vs old and used?

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    Ended up grabbing this set of three, thanks for all of your help i wont be able to reply for a little while i still need to test it out ;)

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  • SpeakerScott
    replied
    Re: Amplifier Building vs old and used?

    Originally posted by DDF View Post
    Bryston was awesome, and mailed me all new caps for the 2Bs for free despite the amps being 20+ years old.

    I "pooged" one of the NADs when I bought it early/mid 80s and used good (for the time) panasonic electrolytics; its caps have been rock solid and outlasted the other amps. It might be because it was in near constant use though.

    At one of the local audio DIY get togethers we hear everything from brute force 70's sand amps to big tubes, Class D, Nelson pass first watt jobs, and novel DIY designs. They all sound pretty good to me except the big old 70s transistor amps which clearly sound very bad and very different from everything else.
    Yeah...the BGW amp is great for cheap power...so is the Crown DC300A stock. Both can be drastically upgraded by improving the op-amp used in the differential stage and for the Crown...cleaning up the HORRENDOUS mess that is their grounding and wiring layout scheme. What the amps have in their favor is a nearly limitless power supply compared to their output rating that makes for a great foundation. You do need to know what your doing though...mis-application of grounding changes can yield crazy instability.

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  • DDF
    replied
    Re: Amplifier Building vs old and used?

    Originally posted by SpeakerScott View Post
    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
    Bryston was awesome, and mailed me all new caps for the 2Bs for free despite the amps being 20+ years old.

    I "pooged" one of the NADs when I bought it early/mid 80s and used good (for the time) panasonic electrolytics; its caps have been rock solid and outlasted the other amps. It might be because it was in near constant use though.

    At one of the local audio DIY get togethers we hear everything from brute force 70's sand amps to big tubes, Class D, Nelson pass first watt jobs, and novel DIY designs. They all sound pretty good to me except the big old 70s transistor amps which clearly sound very bad and very different from everything else.

    Leave a comment:


  • DDF
    replied
    Re: Amplifier Building vs old and used?

    Originally posted by jason171717 View Post
    Do you agree with he train of though that two smaller toroidal transformers are better than one larger one?
    Assuming the single tranny is properly rated for the load impedances presented by the speakers, don't agree. If the idea is to get better separation and headroom between channels, and assuming teh single xformer is properly rated, just use sufficient capacitance on the power rails. Way cheaper and more effective than 2 xformers. Multi xformers only make sense if you have them and don't want to buy a higher rated single. One of the 2Bs had been modded with 2 tranny's, I pulled one out and went back to single.

    Originally posted by jason171717 View Post
    "and no one was too thrilled with i" could that be because of the lack of headroom?
    Maybe that's some of it, but mine was failry powerful and well heat sinked. I listened with it for weeks and it just sounds like an old cheap amp to me. It's hard to describe, but its "grey", not clear sounding. The chip-amp guys swear you need boutique parts to make them sound good, but this had standard r's and c's (name brand, but not fancy). The other thing I really don't like about some of the chip amps is the overload protection circuit (National called it "Spike") which starts to cut maximum output voltage with operation below 4 ohms. I made sure to only use it into speakers that didn't trigger Spike protection

    Originally posted by jason171717 View Post
    "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?
    I was only comparing amps that I mentioned directly in my post. I've listened to all those amps in my post for many months or many years (1 NAD and 1 Bryston for 3 decades) except the LJM amp which I only heard for a couple hours. The ClassDAudio I haven't heard yet but trust positive opinions I hear of it, and given its similar to the LJM, trust that feedback. I almost bought one but bought ncores instead. I offered no opinions on amps mentioned by the other posters, so can't really help you with those

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  • SpeakerScott
    replied
    Re: Amplifier Building vs old and used?

    I should also point out that a lot of vintage gear collectors point to the use of those modules as the start of the "BPC" or Black Plastic ...ahem....Carp period of audio equipment.

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  • SpeakerScott
    replied
    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.

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  • jason171717
    replied
    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

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  • jason171717
    replied
    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?

    Leave a comment:


  • mikejennens
    replied
    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.

    Leave a comment:


  • jason171717
    replied
    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.

    Leave a comment:


  • jason171717
    replied
    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?

    Leave a comment:


  • jason171717
    replied
    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

    Leave a comment:


  • jason171717
    replied
    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?

    Leave a comment:


  • SpeakerScott
    replied
    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.

    Leave a comment:


  • SpeakerScott
    replied
    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

    Leave a comment:

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