Forums https://www.decware.com/cgi-bin/yabb22/YaBB.pl Audio Forums >> Frequently Asked Questions >> Help deciding what amp to purchase https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1578100080 Message started by DVDMike on 01/04/20 at 01:08:00

Title: Help deciding what amp to purchase Post by DVDMike on 01/04/20 at 01:08:00 I have circa 1990 Klipschorns with AK3 crossovers.  I am currently running them off an adcom 555II.  I’ve got more than enough power.  But I’d like to try tubes.  Everyone who has klipschorns says they never sounded better that when they are connected via tube based amp.   What I’d like to do is bi-amp the klipschorns and use the tube amp to power the upper end, mid and high.  I’m really not sure how much power I need from the tube amp.   I was looking at the MODEL SE34I.5  Is this enough power to run both left and right channels to reference levels?  Or would another amp be more appropriate with my speakers? I like that you can add a pass through preamp signal through where I could feed the amp running the bass pins.  If you add this, does it come with a dedicated signal/volume limiter so I can independently control output of the 2 stereo amps?  If it doesn’t, it’s really useless for me to buy the extra output option and I’ll have to split the signal before going to the se341 or whatever tube amp I get. There are some additional up charge options listed.  I’m not really sure I understand all of them to know if I need them or not.  (I understand the cosmetic ones).

Title: Re: Help deciding what amp to purchase Post by busterfree on 01/04/20 at 03:22:41 IMO the SE34I.5 is plenty powerful enough for Klipshorns. What preamp are you using with the Adcom 555II? You may like the SE34I.5 alone or with your preamp. How big is your room? The Adcom 555II has gain of 27 dB, and Input Sensitivity of 1.75V for 200 W into 8 Ω. The SE34I.5 needs 2.5V for full output. I want to try a Decware Ultra for bi-amping, but I don’t have one.   [smiley=embarassed.gif]

Title: Re: Help deciding what amp to purchase Post by busterfree on 01/04/20 at 03:23:57 Welcome to the forum!

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/04/20 at 14:49:31 Buster, thanks for your input.  Can I test the output voltage of my preamp out ports with a voltage meter?

Title: Re: Help deciding what amp to purchase Post by busterfree on 01/04/20 at 14:52:46 Quote: Can I test the output voltage of my preamp out ports with a voltage meter? I don’t know. Hopefully, others will chime in.

Title: Re: Help deciding what amp to purchase Post by Donnie on 01/04/20 at 15:12:28 I'd just look up the specs of the preamp.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/04/20 at 15:12:38 I found think link.   https://audiokarma.org/forums/index.php?threads/simple-way-to-measure-preamp-output-voltage-amp-input-v.799145/

Title: Re: Help deciding what amp to purchase Post by hdrider on 01/04/20 at 16:06:44 Welcome Mike- I would put a call into Steve, it may take while to connect but worth his advice. I played with bi-amp and even tri-amped for years, always sounded good but it wasn't until I pitched it all (except sources) and got our Decware/Omega rig that everything sounded organic and right. If that makes any sense. I would love to hear my Rachel driving some big Klipsch speakers someday. Please keep us posted on your findings and progress. This is a great bunch of Decfans here with a LOT of knowledge and opinions and a fantastic sense of humor. Happy listening, Chris.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/04/20 at 17:30:48 Thanks Chris!

Title: Re: Help deciding what amp to purchase Post by Johnecake on 01/09/20 at 03:15:54 Hey Mike  I have 74 khorns and they were special but hard to tame. Horns do love tubes and the Decware makes them sing. I picked the Rachel 4 years ago because Paul Klipsch once said  What the world needs is a good 5 watt amp. Pick the Rachel or 1 or 2 Zens and you will be set. I have a sub cause I had one but honestly you don’t need it, somehow those little watts drive those woofers just fine and the midrange and top is just plain sweet , the edginess is gone and the liveness pops. Khorns were made for SET amps. I also run a preamp it’s much improved in clarity and balance for me. It’s easily the best sound I ever had in all the gear I vw had thru here.Do it you will love it and the horns will thank you.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/09/20 at 12:39:56 John, thanks for weighing in.  I don’t see the “Rachel” listed on the web site. Does this model go my a different name now?

Title: Re: Help deciding what amp to purchase Post by Lon on 01/09/20 at 13:50:47 It's here: the SE34I https://www.decware.com/newsite/SE34I.htm

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/09/20 at 14:28:32 Got it, Rachel is the MODEL SE34I.5 I was thinking.  Thanks.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/09/20 at 15:00:46 I ordered my “Rachel”. One question I have is about startup.  I’ve never owned a tube amp.  With most modern solid state amps, there is a delay circuit that prevents a thump going through your speakers. Is there any noise / distortion that is sent to speakers during the power up time? Also, I’m used to using a “trigger” cable.  I’m pretty sure this amp doesn’t have one of these to power up instead of using the power switch.  But is there any harm in leaving the power switch on and remotely switching the ac power outlet on and off?  Or must you manually use the switch on the unit? Are the tubes use available for purchase outside of decware or are they proprietary?

Title: Re: Help deciding what amp to purchase Post by 4krow on 01/09/20 at 16:49:45 Since I have owned a Rachel for years (but no more), I can answer these questions for you. First off, tube equipment is not instant on after turn on, unless there is a pre warm up circuit . The Rachel does not have this. Point being the tubes must warm up for awhile before any signal can pass, therefore there is no turn on thump to be had. Neither does it have a turn off thump. It does not have a signal turn on, but can safely be turned on remotely by a device used to turn on audio equipment in sections, such as pre amp, amp Cd player etc. Tubes can be bought just about anywhere, with the buyer beware clause intact. There are many different types, substitutes, and even processes in manufacturing. It can go down the rabbit hole, but that is your choice.

Title: Re: Help deciding what amp to purchase Post by 4krow on 01/09/20 at 17:00:08 I want to add that the K horns are over 100db sensitive, point being they will be totally loud enough with 1 watt of input! The Rachel will do quite well by itself, and I see no reason whatsoever to biamp with this sort of speaker sensitivity. For reasons of better quality you might have some sort of argument, but as far as power needs, the point is moot. In high school, I made set of folded horns of the Klipsch design, and never forgot what 1 watt of bass could sound like. No one could understand why I was making a horn with the driver hidden inside the box. A demonstration baffled them further. 'How can that be?' they wondered.

Title: Re: Help deciding what amp to purchase Post by Archie on 01/09/20 at 17:02:34 In general you might get some soft thumping or other odd sounds during the turn on and turn off.  Steve recommends that volume be kept off for both cycles.  I've never had anything "scary" with my various components though.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/09/20 at 18:42:14 Thanks guys for the additional information.  I plan on testing the Rachel (is this a “friends reference?) without biamping first.  If there is no need for biamping, great!   One follow up to the startup suggestion about turning the volume down.  Can you simply turn your volume down for the preamp feeding the Rachel?  Or do you have to use the knobs on her to do this?

Title: Re: Help deciding what amp to purchase Post by Archie on 01/09/20 at 19:03:17 I just turn down my amp and leave the pre alone.  I think the amp is most important since it drives the speakers.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/09/20 at 21:37:44 Yikes!  From what I just saw on the website, there are orders backed up going as far back as early October!  I’m not even on the list but there are over 100 units ahead of me.  I figured I might have to wait for a week or so to get my options.  I missed the part about it taking 3 or more months.  S there only one person there who does all of the assembly?

Title: Re: Help deciding what amp to purchase Post by Geno on 01/09/20 at 22:56:27 There is one for sale here in the classifieds. Grab it and save some money on an already seasoned amp.

Title: Re: Help deciding what amp to purchase Post by Johnecake on 01/10/20 at 03:28:45 Mike congrats on getting into tubes. It’s a whole different restaurant your eating at now. Night and day difference. These amps are hand built to order by artesian craftsman you HAVE to wait for something this nice to be built.I’m waiting on a new preamp myself. Take the time to read all the stuff you can about tube swapping and breakin while u are waiting. Any chance you live in mid NY ur welcome to come see mine.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/10/20 at 04:36:06 I’m in Atlanta but grew up in central NY.  No plans to visit any time soon though.

Title: Re: Help deciding what amp to purchase Post by hdrider on 01/11/20 at 15:36:25 Mike - If you can find a used Rachel with the options you want, think about buying it (don't take too long though) and you can send it to Steve and have it checked out giving you the life time warranty. I did that on my CSP-3. You can have him do some upgrades also, depending on what you buy. Yes, a long wait for new gear but always worth it. Buy the time you forgot that you have gear being made, you start getting notices about what stage it's in. Then it's in your listening room. I bet you will pass on the whole bi-amp idea keeping things as pure as possible. Happy listening, Chris.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 01/13/20 at 22:19:24 Well, I’m finally on the scoreboard. And my card was charged 10% of the total cost. So perhaps my delivery would be from mid March to Mid April I guess.

Title: Re: Help deciding what amp to purchase Post by mperdue63 on 01/13/20 at 23:30:26 It will be worth the wait! Congrats

Title: Re: Help deciding what amp to purchase Post by DVDMike on 04/07/20 at 21:22:51 I’m now in the “quality control” stage.  What is done in QC that isn’t done in “testing”?  Seems like QC can take some time based on what I’ve been seeing with other people’s units. And once it gets to “packed” status it can be a few days even to get shipped out. I’m still looking forward to receiving my unit.  I’m just getting antsy, especially after being locked down at home. I hope everyone is safe!

Title: Re: Help deciding what amp to purchase Post by HockessinKid on 04/07/20 at 21:48:47 You can always call Sarah for an estimate on shipping date. HK

Title: Re: Help deciding what amp to purchase Post by DVDMike on 04/07/20 at 22:02:42 Oh, okay thanks.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 04/15/20 at 20:44:35 My amp is finally shipping out today UPS ground.  So probably won’t be in my hands until sometime next week. Meanwhile, I’m in the process of resurfacing a pair of speakers (not the ones I’ll be using with this amp). Can’t wait for my new amp!

Title: Re: Help deciding what amp to purchase Post by Lon on 04/15/20 at 21:58:23 Congrats! The long wait is almost over!

Title: Re: Help deciding what amp to purchase Post by Steve Deckert on 04/16/20 at 05:40:09 I suspect a lot of people wonder wonder what the difference is between QC and testing... Testing is basically just seeing if it works after assembly. Voltages are tested and the unit is hooked up and listened to throughout the day while other stuff is being built. You can see a video of this being done here: https://fast.wistia.net/embed/playlists/eogduvonh0?media_0_0%5BautoPlay%5D=true&media_0_0%5BcontrolsVisibleOnLoad%5D=true&popover=true&version=v1&videoOptions%5BautoPlay%5D=true&videoOptions%5BplayButton%5D=false&videoOptions%5BplayerColor%5D=8d6f5b&videoOptions%5BvideoHeight%5D=405&videoOptions%5BvideoWidth%5D=720&videoOptions%5BvolumeControl%5D=true QC consists of a lot of things. First it is visually inspected for scratches, crooked components, loose parts, the right parts, the right configuration, and then if it passes that it is checked to see if it specs out. This pretty much ensures that it is wired correctly. During this process tubes are selected for the amp and tested in the amp, until identical matched sets are achieved in both output but also in distortion signatures. The amplifier often spends several hours being cycled on and off during this process and if nothing needs to be changed a final inspection of the solder joints is done by probing each joint while it is one and watching the scope for any fluctuations. At the same time each joint is visually inspected to be sure it is a wet solder joint with a good shine on it that has penetrated the metal. Some are of course hard to see, so an endoscope is used that can reveal cracks or similar issues you can't see with the naked eye. You can see a small part of this process, checking distortion and channel balance in the video here: https://fast.wistia.net/embed/playlists/1rcffizxtc?media_0_0%5BautoPlay%5D=true&media_0_0%5BcontrolsVisibleOnLoad%5D=true&popover=true&version=v1&videoOptions%5BautoPlay%5D=true&videoOptions%5BplayButton%5D=false&videoOptions%5BplayerColor%5D=8d6f5b&videoOptions%5BvideoHeight%5D=405&videoOptions%5BvideoWidth%5D=720&videoOptions%5BvolumeControl%5D=true If the unit gives a solid performance at the QC bench it is then listened to on a planar stereo test rig because as good as my QC equipment is, after 20 years I have learned that just because something tests perfect doesn't mean it is. The source is a battery operated iPod with 12 tracks on it that I've listened to on every component we make so it has become a great reference due to it's consistency. This set up duplicates the soundstage I would get in the listening room but in miniature right at the bench so I can immediately hear if it doesn't image right or have adequate soundstage depth. On Anniversary gear and or mods, I usually will put it in the listening room and actually use it for a day or an evening or two just to log more hours on those tubes to catch any last minute misbehavers.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 04/17/20 at 20:42:06 My amp arrived today.  Pretty good for ups ground!  Very well packed. I need to go back and find / review the manual to make sure I know what’s what.

Title: Re: Help deciding what amp to purchase Post by GroovySauce on 04/17/20 at 21:45:34 Congrats that’s exciting! Report back and let us know your experience.

Title: Re: Help deciding what amp to purchase Post by DVDMike on 04/18/20 at 00:30:49 Hooked it up to khorns.  Turned off sub and used a 24/96 stereo disk for testing. I noticed a lack of bass.  In changing the the balance I figured out the problem was in left channel.  Had to physically move the left KH to get behind it.  Took out the bass fuse, it was blown!.  I can’t say for certain it wasn’t blown before I started the testing, especially since the big sub is over there. Anyway, it went back to sounding better after replacing the klipschhorn bass fuse. Here’s my initial observation. 6WPS really is pretty darn loud with a tube amp & a klipschhorn.  A was quite skeptical about 6wpc.  But I’ve never owned tube anything before.  But as loud as it gets,  it’s just not quite loud enough for me.  I’m getting into some mild clipping when I turn it up to my maximum listening volume. My plan was, and still is now, is to by-amp the KHorns.  My old amp, adcom 555II (250wpc) was was loud enough before clipping. ( In fact, I’d never heard it clip.) So my plan is to run the bass of the khorns off of the adcom and the mid/highs off the tube amp. But with the adcom the KH’s sounded a bit harsh, especially at higher volumes. I never thought it sounded harsh when I was using for my 76 Cornwalls though. The decware (Rachel) has a variable? pre out to feed the adcom.  And of course the khorns have two speaker level inputs, bass and upper.  (Well, not exactly “inputs”.) The only thing I need to add is some sort of inline fuse to the upper frequency feed to its crossover to replicate the functionality of the speaker. I will say that when played loud, the decware isn’t as harsh on the upper end as the adcom.  So this is encouraging post bi-amp. I’m not sure if I didn’t understand something when I ordered Rachel, but I don’t see where i can adjust the volume of the pass through that I planned to send to the adcom to power the bass.  It it an option?  If so, I must have got it wrong and thought the 2 volume controls I selected were for the pass through not the bass.  So this might present a problem for me because without another piece of equipment I won’t have a way to balance my bass and high frequencies.

Title: Re: Help deciding what amp to purchase Post by GroovySauce on 04/21/20 at 12:38:14 Do you have a SPL meter to check the levels? I'm not familiar with the amp so I don't know about the pass through and if it has a variable output. Sounds like you will need to get some sort of attenuator / passive preamp so you can adjust the levels of the Adcom amp. What are you using as a preamp?

Title: Re: Help deciding what amp to purchase Post by bloodlemons on 04/27/20 at 02:33:59 I believe the two volume controls are for Right and Left channels.

Title: Re: Help deciding what amp to purchase Post by s3steve on 05/25/20 at 18:51:48 There is an option for Variable RCA Outputs. I think you needed to check that box. I'm running Altec 605B's and felt they weren't as loud as I had hoped. Coming from Klipsch Chours I and modified Dynaco MkIII putting out 60 wpc. I ended up buying a CSP3 preamp. That helped but I still feel it may not be enough. I was thinking of Biamping but I have a Markwarts crossover that I'll be hooking up this week and I'll see how that changes things.

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