Ki Choi Posted January 16, 2005 Author Share Posted January 16, 2005 I appreciate the inputs from everyone including options on various amps offered in PMs. Just got rid of a pair of electrostatic speakers and could redirect the fund into my new tube amp education by just buying fully updated amp. OTOH, I enjoy holding soldering iron now and then and making attemps at doing the work myself. I have updated quite a few W5Ms. Let me know if anyone is interested in seeing some photos. It is interesting to read other's experience. I was told that the McIntosh's output transformers used on both SS and tube amps generate their sonic magic. Al's MC-250 must benefit from the use of the output TRs to play similar sound as the 8B even as SS amp. Ultimately, I am looking for sonic imperfection with classic tube sound mentioned above. I have very good 2-D imaging and soundstage from my Khorns and current gear but haven't been able to achieve the deep soundstage with my setups (2002s and '76 Khorns in two different rooms). I am hoping by trying these suggestions, in time I'll get there. Thanks. Ki Quote Link to comment Share on other sites More sharing options...
hoggy Posted January 16, 2005 Share Posted January 16, 2005 Ki Choi, I'm still off work so your welcome to come over any time and check out Al's networks that DeanG upgraded with Auricaps. hoggy Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 16, 2005 Share Posted January 16, 2005 Ki, There's nothing magic about transformers. Good ones simply allow the amp to deliver full power into any load impedance. Poor ones casue ringing and bad frequency response due to leakage inductance. The McIntosh transformers are multifilar wound with extremely tight coupling between windings. Even the Marantz 8b doesn't have as good an output transformer as the Mac. I'm not knocking the Marantz 8b though. It's one of the finest tube amps ever made. I simply believe the Mac amps are slightly better, tube or solid state. I still say that no amp change will be a dramatic as upgrading those Khorns. A machanical device like a speaker is ALWAYS the weakest link in an audio system. Work on THAT! Al K. Quote Link to comment Share on other sites More sharing options...
dlb945 Posted January 17, 2005 Share Posted January 17, 2005 Dynaco Mark IV & Mac 250 thoughts .... The Mark IV design is identical to the ST70 with one key exception; each Mark IV has its own power supply resulting in 100% isolation between a pair. Some say that this gives maximum separation and others claim that the Mark IV power transformer lacks the ability to provide the punch compared to the ST70. One friend in the Atlanta Audio Society uses a pair of ST70 amps, each with driver and output tubes removed from one of the channels with claims of more power punch along with 100% isolation/separation. If the user is fortunate enough to have any Klipsch horn design, none of the above matters because it takes so little power/punch to drive these wooden beauties. Al has an interesting insight regarding big Mac SS amps and it is true that the output transformers used with the best Mac SS units impart a sound similar to a better tube amp. Even Roger-Russell, a retired Mac engineering manager, agrees with Al on the advantage of big Mac SS amps. Roger has a great web site with complete Mac history of all products. Take a spin. My discovery for achieving the floating 3D image we all wish for is two-fold. The discovery relates to both ends of the system, source and speakers. Late one evening after one-too-many Martinis, I got up the nerve to straighten the stylus of a high-end cartridge that came with a used turntable from an eBay auction. A pair of pliers with balsa wood glued to the jaws removed the bend. I went though the alignment procedure, grabbed an old scratched up LP, and let things rip. Pow! I got the first really deep and wide floating image. The location of the instruments was smeared and voices sometimes appeared wide instead of concentrated at a point but I concluded that I was just too cheap to spend money on the right things. Hey I said, I think Ill do the ALK project to see if the image improves. I did so and sure enough, the smears were reduced and voices became more focused. I spent several months installing and comparing tube and SS preamps and amplifiers and eventually concluded that the best combo for my ears was a SS preamp driving a tube amplifier. My personal quest here has seen me update caps/resistors in the SS preamps to improve focus. The tube amps I own include the Conrad Johnson MV75A1, Dynaco ST70 and a pair of Dynaco Mark IIIs. I replaced only the driver caps in the CJ unit but am completely balancing the L/R channels in the ST70. My best SS amp is a Hafler DH500 with extensive mods and it also gives a spectacular 3D image but, I still like the warmth of a good tube amp and I can roll (change) output tubes to change the character of the amp for certain types of music. Im sure the tube sound results from the iron laminations between the output tubes (or transistors) and speakers. More recently, I purchased a used Cambridge D500SE CD Player that is a near high-end unit. It also produces a superior 3D image. Again, my recommendations are, buy and install ALK upgrades and get yourself the best source component you can afford. Then try an amplifier with output transformers. There is nothing like the POW and warmth! >>>From too many words Dan Quote Link to comment Share on other sites More sharing options...
sunnysal Posted January 17, 2005 Share Posted January 17, 2005 one small observation about dan's remarks. the mkIV is superior to the st-70 in the ps section as well since each monoblock has its own ps trannie, the st-70 split the single ps tranny between the two output sections...I think he just mixed up his wording...regards, tony EDIT: I should note that the mkIV and ST-70 used different PS trannies the st-70 used one PA60 and the mkIV two PA135, this could be why some prefer the ST-70 Quote Link to comment Share on other sites More sharing options...
Cal Blacksmith Posted January 17, 2005 Share Posted January 17, 2005 I think you should put a bit of weight n Guys input. He directed me to a MUCH better pre-amp than I would have thought I could afford! Thanks again Guy! Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 17, 2005 Share Posted January 17, 2005 Dan's quote: "I spent several months installing and comparing tube and SS preamps and amplifiers and eventually concluded that the best combo for my ears was a SS preamp driving a tube amplifier. My personal quest here has seen me update caps/resistors in the SS preamps to improve focus. The tube amps I own include the Conrad Johnson MV75A1, Dynaco ST70 and a pair of Dynaco Mark IIIs. I replaced only the driver caps in the CJ unit but am completely balancing the L/R channels in the ST70. My best SS amp is a Hafler DH500 with extensive mods and it also gives a spectacular 3D image but, I still like the warmth of a good tube amp and I can roll (change) output tubes to change the character of the amp for certain types of music. Im sure the tube sound results from the iron laminations between the output tubes (or transistors) and speakers." Interesting thoughts. After trying many (too many!) different combinations of tube and solid state preamps and amps with my RF-7s, I finally settled on the best combination for my ears - and it is also a ss preamp/tube amp combination. My Marantz 7T and Mark IIIs are staying with the RF-7s. After I rolled some KT-90s in the Mark IIIs, the results were astounding. I am still sticking with all tubes running my Belles (a Peach and my Marantz 8B - soon to be rebuilt by Dr. Dave). But, there is something to be said about a good solid state preamp and tube amp combination. Carl. Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 17, 2005 Share Posted January 17, 2005 Double post - again!!! *&^%$@! (A generic utterance designed to comply with the forum's announced policy) Carl. Quote Link to comment Share on other sites More sharing options...
dlb945 Posted January 17, 2005 Share Posted January 17, 2005 Ditto on the KT90's Carl ... I love them with Gin. Genalex KT88 Gold Lions (came with Mark III's) sound better but I keep them boxed to sell for future equipment. They may be worth more than the value of the Mark III's!! >>>Dan Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 17, 2005 Share Posted January 17, 2005 ---------------- On 1/17/2005 6:53:46 PM dlb945 wrote: Ditto on the KT90's Carl ... I love them with Gin. Genalex KT88 Gold Lions (came with Mark III's) sound better but I keep them boxed to sell for future equipment. They may be worth more than the value of the Mark III's!! >>>Dan ---------------- Gulp.....I should say so. Find the right buyer in the future, and you could add on another nice piece of equipment to your rig just on that sale alone!! That's my future quest. After my Marantz 8B is reworked, just hoping (unrealistically) to find a nice quad of KT77 Gold Lions at some estate sale for pennies on the dollar(just like Thebes found his 8B). Well, we can always hope, can't we??? Carl. Quote Link to comment Share on other sites More sharing options...
Ki Choi Posted January 18, 2005 Author Share Posted January 18, 2005 Thanks to one of the fourm members, Tricerstops, I will be able to listen to an 8B with Khorns and form an opinion. I was alerted about a, relatively local, 8B at a dealer in Portland where I had earlier rescued one of the Khorns last year (Triceratops witnessed the setting of the Khorns free at the dealer - as I later found out) via email. I just called and got it. Unfortunately, I am in Asia for the next two weeks and the amp will wait for me when I get home. (Hoggy, thanks for your note and I will definitely drop by your place when I return). So the fun begins all over again... Ki Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 18, 2005 Share Posted January 18, 2005 The 8B will make you a believer. After you get it, you may want to carefully take off the bottom and post pics before firing it up. That way the Marantz faithful (and knowledgeable) such as Guy, SunnySal, Wolfram, and Dr. Dave (Audiokid) can tell you if it is bone-stock or if it has had any upgrades done. When I picked my 8B up last fall, it was basically stock and sounded very good when I fired it up. I probably should have brought it up on a variac but did not know better. With anything mechanical- almost forty years old, if stock, there are parts that need to be replaced and/or upgraded. That's where mine is headed next week. Another 8B convert. Brings a tear to the eye.... Carl. Quote Link to comment Share on other sites More sharing options...
Ki Choi Posted January 18, 2005 Author Share Posted January 18, 2005 Al: The dealer who had 8B also had 10B tuner (got committed before I could get to it) but had 7T SS preamp and a mint MC2105. Not knowing too much about the Mc gear, I wonder if MC2105 would be equal to your MC250. I plan to obtain the Mc250 as well to compare. How about the 7T SS preamp? Any thoughts on it compared to the 7 Tubed one? Ki Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 18, 2005 Share Posted January 18, 2005 Ki: Some have said that the Marantz 7T is a tad bit brighter that the tubed pre it replaced. That being said, it has a great reputation for being a detailed, warm-sounding SS pre. I own a 7T, and pair it with my Mark IIIs - it is a glorious combination with my RF-7s. I have also run the 7T with my 8B, and that is also a great combination. The only reason that my 7T is not paired up with my 8B is because the 8B gets my Peach tubed pre/pro, which is an incredible pre with a HT bypass (which the 7T does not have - hey - my system's complicated). But, the 7T is no slouch, and I could have also been happy running the 7T and the 8B with my Belles. In my opinion, for what they have been going for on the open market, the 7T is a steal as a preamp. Sunnysal also runs a 7T with a tube amp - and loves the combination. Carl. Quote Link to comment Share on other sites More sharing options...
Ki Choi Posted January 31, 2005 Author Share Posted January 31, 2005 Here it is. It was waiting for me when I got home. I will post the photos of its inners in next two posts. Ki Quote Link to comment Share on other sites More sharing options...
Ki Choi Posted January 31, 2005 Author Share Posted January 31, 2005 It seems the 8B had been serviced before. Here's what I can tell from a quick overview: 1) All the irons look to be original 2) Tubes are mixed bag of brands. The previous owner must not have been a critical listener. One of the driver tubes is an odd number and B side of output tubes are Russian made. 3) Some of the resistors were replaced. The new resistors seem to be just common carbon type from 10 years ago. The soldering work looks excellent and no faults. The work must have been done long time ago since its finish had changed color as almost the same as the original ones. Quote Link to comment Share on other sites More sharing options...
Ki Choi Posted January 31, 2005 Author Share Posted January 31, 2005 I will use a variac to power it up. Any advice and comments would be much appreciated. Ki Quote Link to comment Share on other sites More sharing options...
triceratops Posted January 31, 2005 Share Posted January 31, 2005 Ki, Your 8B looks beautiful--I didn't get a chance to see it before it was shipped by the store and it appears to be a prime example. If it sounds as good as it looks, you should be in for a treat--I'm looking forward to your review! Best in horns, triceratops Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 31, 2005 Share Posted January 31, 2005 Congrats, Ki - it does look beautiful. As you probably already know, the right NOS tubes can make this baby sound even better. On Friday, I received some NOS RCAs (RCA 6CG7 Clear Top 1960s; RCA 6BH6 Black Plate 1950s). Wow, what a difference. Talk about a smoother, dynamic and more detailed midrange (if that was possible). Let us know your impressions after you bring her up. Carl. Quote Link to comment Share on other sites More sharing options...
hurdy_gurdyman Posted January 31, 2005 Share Posted January 31, 2005 ---------------- On 1/14/2005 9:55:27 PM Ki Choi wrote: Well, I got the itch for the most warm and airy sounding tube amps for my Khorns. I am getting satisfyingly accurate sound from HK Citation IIs, HeathKit W5Ms, and Bel Canto SET40 in my set up. Now, I'd like to experiment for different sound from a tube amp doesn't have to be so accurate but produces classic warm and airy tube sound. I have had a modern EL34 tube amp for a pair of B&Ws once before that was pretty close. I am considering about Marantz 8B. Let me hear from Khorn/8B owners. Any other suggestions? Thanks, Ki ---------------- Here's a thought for an inexpensive amp that has a clean, classic sound that's both airy and warm. An old Bell 2024 (or is it 2420?). These are a 6V6 based integrated with 12AX7 drivers and preamp tubes. Smallish output transformers and a simple circuit. Very clean and airy mids and highs with a good touch of "classic tube warmth". Drawbacks are a phono stage that doesn't have enough gain for most cartridges (hums) and the bass is underdamped (mushy). This may not be a problem with well damped horn bass, but was an irritant with regular box speakers. When a sub was used the amp sounded fine on box speakers crossed at 80Hz. This amp is very relaxing and throws a good soundstage. Someday I'm going to rebuild my power supply and use it again. http://pg.photos.yahoo.com/ph/the_hurdy_gurdyman/detail?.dir=6d5d&.dnm=b4e4.jpg&.src=ph They can be found for under $200 and are simple to work on if repairs are needed. Dave Quote Link to comment Share on other sites More sharing options...
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