johnellis

Erik- Like you, I guess I'm in the remaining one per percent who hasn't figured all this stuff out either. I'm definately still learning myself. It's definately fun to share ideas and in the process learn. I'm definately learning alot. That's for sure. Your posts are excellent and you've already helped me out a great deal. And I appreciate it very much!!! Oh, and yes. I knew you were referring to a tranformer-coupled passive. I am very, VERY interested in this. And, once again, I definately want to build one. The question is, which one??? As mentioned, if we all share ideas, maybe we can come up with something that might not be too difficult to build. At least for the first go-around anyway. John

Guy- You are very welcome!! P.S. Regarding the DACT price list. I didn't do the Euro conversion. I apologize for the mistake. John

And here is the current DACT price list (from the Netherlands) as of February, 2004. Of course other components could be substituted. But, once again, this is merely a reference point. John > Dear Mr. Ellis, > > Enclosed you'll find the requested prices, these are in Euro: > > DACT: > CT1-mono 83.91 > CT1-stereo 113.96 > CT1-balanced stereo 207.94 > CT2-mono 55.28 > CT2-stereo 73.47 > CT2-balanced stereo 128.94 > CT2-triple stereo 193.31 > CT2-8 wafers 253.81 > CT3-5-4 46.63 > CT4-balance control 125.37 > CT100 469.02 > CT101 108.07 > CT102 197.71 > > Acc. > CT-knob1 9.30 > CT-knob2 11.70 > CT-knob3 14.70 > CT-knob4 21.60 > CT-ext1/S 8.80 > CT-ext1/L 9.80 > CT1-conn1 9.09 > > Transport, packing, handling & insurance costs (total): > > to EC countries 32.00 > to other European dest. 33.50 > outside Europe 40.00 > > If the total of ordered DACT items (not accessories!) exceeds > 5 pieces (CT100/101/102: 2 pcs), an additional discount of 10% > will be given on the merchandise. > > * Private customers of the EC countries will be additionally > charged for the Dutch VAT of 19% on the overall total. > Private customers from outside the EC won't be charged > by us, but may be charged a local sales tax, depending > on local tax regulations. For companies within the EC VAT > is not charged if a valid VAT number is supplied. > > International delivery is anything up to 10 working days, this > depending on destination. All orders are insured for the full value. > We can send the goods after receipt of your payment, > please choose one of the following ways: > > - payment in advance on our bankaccount, our bankdata > you'll find below, We'll give a discount of 5% on the overall > total if the bankcosts are SHARED (use the IBAN and BIC). > - by means of PayPal, please visit www.PayPal.com and use > info@audiocomponents.nl as benificiary email address > - or by charging your Mastercard/VISA account, > please supply us with your accountnumber, exp.date, > cvc-code (last 3 digits on back of your card), the name > on the card and also the name of the issueing bank. > > Please let me hear what you prefer and if you want to order, > don't forget to send us your full address data for invoicing > and shipping. > > best regards, > Rolph Smulders > > Audio Components BV > Ussenstraat 2a > 5341 PM Oss, the Netherlands > tel +31.412.626610 fax +31.412.633017 > www.audiocomponents.nl > info@audiocomponents.nl > > bank: RABOBANK OSS > Raadhuislaan 26 > 5341 GL Oss, The Netherlands > > International Bank Account Numbers: > IBAN: NL94 RABO 0140 4428 20 > BIC (SWIFT): RABONL2U

Transformer-Coupled..... Transformer-Coupled, CT2-10K-2 and one CT101: Transformers convert from balanced to single-ended operation, as well as rejecting environmental noise. The input transformer primary is connected to pins 2 and 3 of the XLR connector, but the shield is not connected to the preamp chassis, electrically isolating the preamp chassis from the console. The output (line-driver) transformer converts back to balanced signals, and the cable shield can be isolated or connected to the preamp chassis, depending on the ground-switch position. Transformer operation breaks the ground connection between distant electronic components, preventing ground loops. Frequencies above 100kHz are steeply attenuated, preventing AES/EBU digital noise, NTSC/PAL television interference, and computer-generated EMI from entering the electronics of the console, the linestage, or the powered monitor. The filtering and ground isolation prevents the high slewing speed of the CT101 opamps from being "used up" by non-audio RF interference. Studio-quality transformers are available from Jensen (USA), Lundahl (Sweden), Sowter (UK), Stevens & Billington (UK), and many others. Input and output (line-driver) transformers have different characteristics, so select the appropriate part for each application. Transformers do have limitations: they don't accept DC offsets, distortion below 5 Hz is high, and the transformer must be driven from a fairly low impedance (less than 600 ohms) for full frequency response.

Erik- Excellent post!!!! Now you have me thinking of building another passive!! Anyway, I've been doing some research regarding active linestage and transformer-coupled and there's definately alot of information out there. On the web that is. The first place I hit was the DACT site. And yes, there are many others as well. But, this does give one some good ideas and its a good starting point as well. Would anyone be interested in building one? If so, maybe we could put our heads together and do it. Once we have finished a pair of working prototypes, we could then post our results here. Anyway, just a thought. Okay, some of the information I have found so far.....Active linestage. CT101 Active Linestage: If you want to drive more than 1 meter of cable, consider the CT101 linestage and one or two CT102 power supplies. The ultrafast opamps in the CT101 are the most transparent available, provide a selectable gain of 0, 6, or 12dB, and have enough current delivery to drive long cables with no trouble (5 meters or more). The CT101 has two independent channels - even the power supply and grounds are isolated, allowing separate power supplies if desired. The CT2 stereo control plugs directly into the CT101 circuit board, removing the necessity for hookup wires, and keeping the signal path as short as possible. If you want 6 channels, a single CT2-10K-6 volume control plugs directly into three CT101 linestages, as shown at the top of the page. A high-quality active linestage can be just as transparent as a passive preamp, with noticeably better dynamics and bass control. The testimonials of DACT customers give a sample of what you can expect from an active preamplifier based on the CT2-10K-2 control, CT101 stereo linestage, and one or two CT102 power supplies.

Kelly- You are absolutely correct regarding the transformer coupled units. But, that's an entirely different beast. Well, for the most part. Many people swear by them though. I will most definately try this as a future project. I have yet to hear one. Anyway, I just thought I would post this mess just to give people an inexpensive way to experiment. For me, not only is it alot of fun but it is also a big bang for the buck as well. It pis*ses me off when I think of the thousands of dollars I have spent over the years in search of active preamp audio bliss only to find out that a $20.00 to $200.00 DIY passive can sound every bit as good (if not better) than a 2, 3 or even $4000 active tube or SS. Boy, was I ever a sucker!!

mdeneen- You're right, the term "passive preamp" is more or less an oxymoron. It is "pre-amp", meaning it comes before the amplifier therefore I guess that's why some people, including myself, call it a preamp espite the fact that it is passive. In a similar fashion, post amp would be an LPAD (Nasty word!!! ) If the attenuator was installed in a CD or the amp itself, then I would normally refer to it, as would most people, as merely a volume control. However, the amp does see this, meaning the passive preamp or attenuator, as a source. But, who knows. And who cares!!! Not worth quibbling over. Oh, and yes, you're right again. Many CD players do in fact had a level control and 2V out capability. BUT, this was a $500.00 option for my Cary. The volume control that is. For that matter, I could build something of very high quality for half that. Also, I'm running a tri-amped system. My CJ 52's do not have volume controls nor do my Moondogs. In short, I really do not want to modify them. Hence my reason for searching out an alternative. After A/B'ing high end active tube and SS preamps with high end passives there is no doubt that the latter is superior. For me, I will never go back to an active. Be it tube or SS. Too much of a "veil" over the music". LESS IS BETTER. At least in my mind. And Ears!!

Prototype parts list...... (1) Radio Shack aluminum project box 27-238 (I think*) $2.99 ea (2) Radio Shack 50k linear pots 27-1716 $2.49 ea (1) RS pack of 5-10k 5% carbon film resistors 27-1126 $.99 ea (1) RS pack of 4-RCA audio jacks 274-346 $2.99 ea (1) 60' roll 18 gauge solid core wire 278-1217 $3.99 ea (only need about two feet!) (2) Knobs (Any will do) Total cost = Under $20.00 Final parts list (only a suggestion) Use a quality enclosure. Maybe somthing from here..... http://www.par-metal.com/ Use a DACT attenuator or TDK pot (latter recommended by kelly) Vishay or Caddock resistors Cardas RCA audio jacks 20 gauge 99.9999% silver wiring Teflon tubing (for the silver wire) DACT knobs (or maybe purchase some from Audio Research. Or anyone for that matter) Total Cost = $150.00 (give or take) Assembly instructions..... 1. Mark openings for gain pots 1-1/2" from each side and 1/2" from top on front of project box chassis. Drill pilot holes using 1/8" bit. Follow with 17/64" bit for full size opening. 2. On back side of project box, mark openings for input and output jacks 1-1/2" from each side and 5/8" from top and bottom, respectively. Drill holes using same size bit sizes as before. 3. Using Dremel tool or hacksaw, trim length of gain pot "axles" to desired length based upon choice of knobs. 4. Install gain pots to project box. For each pot, insert from back side into opening on front panel, place washer and affix with lock nut. Orient connectors in mirror imaged pattern to provide clearance for wiring. Bend connection tabs forward. See photo. 5. Install audio jacks to back panel of project box. For each, insert jack, place lock washer, and affix with lock nut Orient connectors with ground tab in mirror imaged pattern to provide clearance for wiring. See photo. 6. Cut (2) lengths of solid core wire to 1-1/2". 7. Cut (2) lengths of solid core wire to 3". 8. Cut (4) lengths of solid core wire to 2-3/4". 9. Strip 3/8" of each end of wire sections. 10. For each channel, attach 1-1/2" length of wire from ground tab of lower input terminal tab (input) to ground tab of upper input terminal tab (output). Fold exposed end of each wire in half and crimp lightly using needle-nosed pliers. 11. Complete left channel wiring. Attach 3" wire section to pin 3 of pot to ground of input jack (lower). Attach first 2-3/4" wire section to pin 2 of pot to center pin of output jack (upper). Attach other 2-3/4" wire section to pin 1 of pot to center pin of input jack. Trim leads on resistor by 1/2" on each side. Attach one end of resistor to center pin of output jack (upper) and other end to ground tab of output jack. 12. Complete right channel wiring. Attach first 2-3/4" wire section to pin 1 of pot to center pin of input jack (lower). Attach other 2-3/4" wire section to pin 2 of pot to center pin of output jack. Attach 3" wire section to pin 3 of pot to ground of output jack (upper). Trim leads on resistors by 1/2" on each side. Attach one end of other resistor to center pin of output jack (upper) to ground tab of output jack. 13. Gently crimp ends on all wiring connections together. Before soldering connections, test out unit. 14. Following successful circuit test, solder all connections. Apply heat to wiring, wait, and apply solder to connections. Allow solder to flow and create bead for each connection. 15. Affix cover with 4-sheet metal screws. 16. Attach knobs to gain pots. That's it!!!!! Now you're ready for testing. Testing (Important).... Test it very carefully, preferrably into another working preamp or volume control, to make sure you wired it right. If something is reversed you could end up blasting a full-scale signal into your amp, or get a very loud hum. Set it fully counterclockwise, then slowly turn up your other safety volume control to be sure the signal is properly attenuated. Once you are sure there is no signal or noise, slowly operate your new passive preamp with the other preamp at low volume to be sure everything is ok. NOTE: Please read the issues regarding length of interconnects (passive to amp). They should be as short as possible. If you have read the above links you will already be familiar with this as well as the issue of the 2v source output. Not a big deal. Most sources provide this.

Kudret (and others)- Here is the information that you guys have requested. In short, start out building a working prototype using cheap components. Once you have it where you think you want it, then of course upgrade using higher end attenuators or pots, RCA connectors, etc. Everyone's "ears" and "systems" and or "applications" are different. Hence it's very important to experiment with different resistors and volume controls in order to find the right match for your system. I will say this though, my $20.00 (yes, $20.00!!!) el cheapo rat shack crapo passive preamp kicked the sh*t out of my Audio Research SP8 and Conrad Johnson PV5. In terms of "clarity" and the "unveiling" of the music that is. It has also been A/B'd against other high end active preamps such as Cary and McIntosh and in each case it has held its own. If not surpassing them. Anyway, please do not take my word for it. Spend the $20.00 @ rat shack and take 2 hours out of your day and find out for yourself!!! One note, this isn't my idea but rather the idea of many. I've also attached a photograph of a similar working prototype. Informational resources (read before building...take in all the information you can.) http://www.diyaudio.com/forums/showthread.php?threadid=2608&perpage=15&highlight=&pagenumber=1 http://www3.sympatico.ca/r.godmaire/Passive_Preamplifier.htm http://sound.westhost.com/project01.htm http://www.enjoythemusic.com/magazine/equipment/899/dactct1.htm http://www.nutshellhifi.com/ Okay....I'm off to take the pooch to the park. I will post the parts list and wiring instructions upon my return. John

Kudret- I will be more than happy to provide the information you requested. I'm currently at work therefore I will send it out tonight. In fact, I will just start another thread. I've had other forum members asking me similar questions therefore this might be the easiest. Anyway, once again, I will post it tonight!! John

Don- I haven't heard a TDK potentiometer in and of itself, such as in a passive preamp, although I do believe my ARC SP8 uses one. For the past six months I have been using a DACT CT2 and I love it. diycable.com sells them although they are quite expensive. $182.00. BUT, I know a place in the netherlands (Audio Components BV) where you can buy them for $73.47. At the moment I cannot remember the URL but if you're interested shoot me an email and I'll find it for you. Also, if you're interested in building a passive preamp I have a wonderful yet very simple design I found out on the internet. Let me know on this one as well. I'd be happy to send the info or post it here. Anyway, the passive sounds absolutely wonderful and it's VERY inexpensive and simple to build. In short, it will rival active preamps in the $4000 price range. The sound is extremely clean and clear. I think Artto said it best in another post. It's as if a veil has been lifted. Needless to say my CJ PV5 and ARC SP8 are now for sale!!

Oh My !!!!! A Rare Apperance from Master Ellis!!!!! Vacation went well. Will call you soon. Regards to "15 second AK47 Olga." tc ---------------- Hi Terry!! Hey, I called you the other nite. Unfortunately you were still at work. I'm glad your vacation went well. Although I'm sure it was much to short. I'll give you a call sometime this week or weekend as well. With any luck we'll link up. Oh, and yes, I passed your regards on to the "Kalashnikov Kid" as well!! By the way, have I mentioned she's highly trained in chemical and biological warefare as well??? Believe me, when I'm told to do the dishes I JUMP!!! Will call you soon as well. John

If the A7 cabinets are not local, have you considered using JBL 4560's? They are somewhat smaller (more like an Altec 816)and they work really, really well with Altec 515's or 416. In fact, I actually prefer the 4560's over the A7's (I have both) because of thier size. They take up less space in the living room. If you are in a fairly large city, check with the used pro gear shops. They, meaning the 4560's, are pretty easy to find.

On 2/16/2004 5:30:42 PM BigBusa wrote: "Can you tell I HATE ALTECS? The hype festooned on these speakers is incredible. There's no way they can live up to it." In the hands of an idiot, you are absolutely correct.

---------------- On 2/14/2004 1:23:04 AM BackBurner wrote: There nothing to write home about , i've heard them . ---------------- The ones I heard were being driven by a huge ARC D79 on the low end and a pair of MC30's on the high end. They sounded great. And yes, they were in fact something to write home about!! At least the ones I heard anyway.

These are wonderful LF cabinets. Someone on the board should bid on them. If wasn't already over stocked with gear I would definately bid on them myself. Anyway, just thought I would pass it along. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3076871571&category=3284

Hi Piranha- If you go to audio asylum.... http://www.audioasylum.com/audio/index.html will will find alot of information about the 1570. Also, go to... http://www.high-endaudio.com/RC-Amplifiers.html This is another good site. Here is the information from high-endaudio. From what I understand, a stock 1570 sounds terrible. But, once they are modified, they are world class. Anyway, here is some information that might help. John ALTEC 1570/TUTAY MODIFICATION This "vintage" Altec is a fantastic amplifier. It could be the "dream" amplifier for many audiophiles. I didn't list it initially because of the many hurdles to get an optimized working pair, and the potential danger in using them. Let's discuss the sonics first, and then tackle the rest. This amplifier, after it is fully modified, can compete with virtually any push-pull amplifier in the world. It uses only two 811A direct heated triode output tubes, but it can still generate over 150 watts per channel. It has a very high quality power supply with chokes, tube rectification, separate input and output supplies etc. The end result is a combination of tremendous power along with a lot, but not all, of the purity and transparency of the single-ended designs. Other "high-power" tube amplifiers, that use multiple output tubes (8, 12, 16, or 20 per channel-especially pentodes) to create their power, can not compete with this simpler (and much less expensive) design. As usual, it is at its best with high-impedance loads, but it can still sound excellent in normal impedance loads as well, though it is not recommended with very low impedances. Now for the inevitable "hurdles": 1. The original Altec 1570 series of amplifiers were designed and built for "commercial" and "industrial" applications; The military, sports stadiums, factories, auditoriums etc. They are very reliable of course, and are also downright ugly in appearance. There may have been many made 40 years ago, but now they are difficult to find. Their sonics, stock, are horrible. They sound "dirty" and have no bass. So they must also be modified. 2. There are very few people who can modify these amplifiers. The person who has the most experience, and has achieved the finest results we've heard, is Tom Tutay, a talented engineer who lives and works in Florida (Go to "Links" section to contact him). So after a pair of these are found in good condition, they must be sent to Tutay for his (very extensive) update. I don't know the most recent cost, and there are some options, but it will cost at least $ 3,000, or more. Considering the enormous amount of work involved, this is a very fair price. The total cost, including the amplifiers themselves and all the shipping, will be in the $ 5,000 range, unless you can "score" on the Altecs. To put things in perspective, if such an amplifier were built in North America and marketed new in today's market, it would sell for a minimum of $ 10,000 and probably around $ 15,000 or more. 3. After all the above has been done, there is another important issue to ponder. The reason why these amplifiers can generate so much power with only two output tubes is simple; there is more than 900 volts DC on the plates. This voltage itself comes from the rare, high voltage power transformer, which has somewhat louder than average "mechanical noise". (The extra expense and difficulty in finding and utilizing very high voltage components is the primary reason why contemporary amplifier manufacturers haven't just copied this design.) Unfortunately, there is a potential danger to this design. The 811A output tube receives this high voltage from an (easily accessible) cap on the top of the tube, and not from the usual, inaccessible tube pins within the chassis. This means that anyone (or anything) who removes this cap while the amplifier is "on", or even "off" for a short period of time, and touches the internal metal part, can be electrocuted. I realize only a reckless fool or someone incredibly ignorant would do this, but I felt it should still be mentioned. The Altec came with a perforated, protective cover which made it impossible to reach the cap, but it may be missing, and some people may prefer not to use it because the 811A output tubes look "cool" when they are "on" and all "lit up". This is highly unadvisable. My advice is to do whatever it takes to make these plate caps inaccessible to others; a replacement cover, screen etc. Don't worry about "ruining" the appearance of this amplifier, it can't be made any worse than it already is. Once that is done, this amplifier is as safe as any other tube amplifier, and very reliable. One final concern also deals with the Altec's very high voltage. A reader has informed me that an electronics designer warned him that the amplifier can "emit high radiation levels". The designer's advice to an Altec owner is simple: "He will want to distance himself as much as possible from those amps..." This advice is also applicable with any other electronic device using high voltages; such as televisions, some older computer monitors and even "typical" tube amplifiers etc., so this information doesn't compromise the Altec 1570's recommendation except in very highly unusual circumstances. Tom Tutay, the modification expert and engineer, also feels the amplifier is "very safe". (20 or more of these Altec amplifiers were used in the Astrodome and they were on 24 hours a day. The engineers who worked in near proximity never had any problems with them.)

The B3 is from an early 80's Cornwall. John

Fini, Chris, Randy....I couldn't have said it better myself. He will be greatly missed. I too haven't thought about him in years. But now I do. I still chuckle at the thought of all those ping pong balls falling from the ceiling. Those were wonderful times.

motobret- If you're interested, I have an extra pair of Chorus crossovers. They are from a late model Chorus I and I am quite sure they would work just fine in the Chorus II. Anyway, if you're interested let me know. John

"The VOTTs are public address speakers. All mid and not much more." It is better to keep one's mouth shut and be thought a fool than to open it and resolve all doubt. ~Abraham Lincoln.

Q-man I apologize for not fully explaining in my post. But yes, I totally agree with you as far as a marriage between the different manufacturers is concerned. An Altec/JBL top end along with the Khorn bassbin would in fact be the ultimate!!! I was thinking more in terms of the upper mids of the 515B in a reflex/horn loaded enclosure such as the 816, 828 or JBL 4560 verses the upper mids of the K33 in a Cornwall/ported cabinet. The low end is where the Khorn really sings, IMHO. Personally, once again, just my opinion, a fully tweaked VOTT, along with a quality crossover (important key) and good upstream tube gear (another important key) will run circles around a "stock" (another key word) Khorn. With of course the exception of the low end. Which is something I failed to mention before. Once again, I apologize for this.

I'm in the VOTT camp as well. IMHO, a properly setup Heritage, when compared to a properly setup VOTT, will be out classed everytime. The VOTT is far superior. At least as far as my ears are concerned. A K33 is not even in the same league as a 515B. This is without a doubt one of the best woofers ever made. Nor can a K55 and K400 compete when compared to a 290, 288, 802, 806 or 902 attached to a 311, 805 or 511. The midrange, once again, is FAR superior. Furthermore, if a tweeter is required, a JBL 2404 is much better than a K77 as well. When using these components in a ATLEC A7 or JBL 4560, properly damped and braced along with a high quality passive or active crossover and quality tube gear upstream, they are absolutely AMAZING!!!! By far one of the best speakers I have ever heard. No matter what the cost. As a result, I can never go back to Klipsch. Even though I still love my Heritage!! Anyone who would say otherwise just hasn't heard a VOTT that has been tweaked to the enviornment in which it resides.

For me it's.....buy American, marry foriegn.

What? The A7's suck????? Man, I find this extremely hard to believe. The A7's that I have heard in the past, and, the ones that I currently own, will simply blow away any of my Heritage. A7's that are properly setup that is. The 515 upper bass and the 288/805 midrange actively crossed is BY FAR one of the best I have ever heard. At ANY price!! Either A, something was wrong with your A7's. B, your amplification and or other upstream components were ****. Or C, you're completely deaf.