artto Posted January 27, 2005 Share Posted January 27, 2005 Grommes http://www.grommeshifi.com/products/260a/260a.htm Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 27, 2005 Share Posted January 27, 2005 nope Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted January 27, 2005 Share Posted January 27, 2005 Haven't heard of them before, but their design and marketing is really cool. Retro 50's. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted January 27, 2005 Share Posted January 27, 2005 it´s an alan kimmel re-work of the orignal. I have not encountered anyone who has heard it, it was mentioned (and pictured) in a recent stereophile, AFAIK it has not been reviewed as of yet. regards, tony Quote Link to comment Share on other sites More sharing options...
artto Posted January 27, 2005 Author Share Posted January 27, 2005 ---------------- On 1/27/2005 5:15:26 PM sunnysal wrote: it´s an alan kimmel re-work of the orignal. I have not encountered anyone who has heard it, it was mentioned (and pictured) in a recent stereophile, AFAIK it has not been reviewed as of yet. regards, tony ---------------- I don't know who Alan Kimmel is (lol). Is he someone I should be aware of? I heard these last summer when I was shopping around for a new SACD player at Holms Audio in Woodridge, IL Quote Link to comment Share on other sites More sharing options...
sunnysal Posted January 27, 2005 Share Posted January 27, 2005 Artto, He a pretty well known amplifier designer. Welborne Labs sells his Dynaco upgrade boards and I seem to remember a 845-based design of his is VERY popular, he also works closely with Lundahl transformers if I remember correctly. Tony Quote Link to comment Share on other sites More sharing options...
blindman Posted January 27, 2005 Share Posted January 27, 2005 I have a copy of an excellent reference book by Bruce Rozenbilt, "Beginner's Guide to Tube Audio Design" (ISBN # 1-882580-13-3, First Edition 1997, Audio Amateur Press, 104 pages, $24.95) The dedication page states: "This book is dedicated to all of the vacuum tube designers of the 20th century whose work gave us this wonderful technology of music reproduction, and to the designers of the 21st century who will carry their legacy even further". Chapter 11 contains info pertaining to the "CLASSIC DESIGNS". Among those discussed are: Jefferson 2A3, Williamson Amplifier, Leak RC/PA/U, Fisher 50-AZ, Grommes 260A, Dynaco Mark III, Heathkit W-6M, Mcintosh MC-60, Marantz Model 5, Grommes Model 212, and Dynaco PAS-2. This book includes schematics and describes how the circuits, and various types of tubes, work! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 27, 2005 Share Posted January 27, 2005 Your right that is a great book ! It's so great a few years back I bought 2 by mistake LOL !! Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted January 27, 2005 Share Posted January 27, 2005 I've heard their 360 monoblocks at CES this year. It was nothing special. Quote Link to comment Share on other sites More sharing options...
tillmbil Posted January 27, 2005 Share Posted January 27, 2005 Oh I will just go right out and buy that book Craig. Sounds like great reading. right Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 27, 2005 Share Posted January 27, 2005 I heard these last summer when I was shopping around for a new SACD player at Holms Audio in Woodridge, IL ---------------- holm audio is great i live about 15 min from there!!! Quote Link to comment Share on other sites More sharing options...
sunnysal Posted January 28, 2005 Share Posted January 28, 2005 gramas....you forgot to mention how they sounded...LOL! tony Quote Link to comment Share on other sites More sharing options...
artto Posted January 28, 2005 Author Share Posted January 28, 2005 I was hoping more folks had heard these before I jumped in with my 2 cents. First let me say that I dont particularly like Holms Audio. Some of the stuff in there is such, well $$$$peaker cables you could anchor a ship with connected to $15k large bookshelf speakers (LMFAO). Most of the rooms are very small. The acoustic treatment products they sell are for the most part, laughable, etc., etc. However, they are very nice people. As for the Grommes amps, I was sitting around waiting so I listened to one of their systems (second from the top, I think). The music playing is what kind of caught my attention. I believe the speakers were Joseph Audio RM30si (MSRP $4300) or the RM50si ($6000). The CD playing turned out to be the music soundtrack from Patriot Games. I didnt have the recording & its out of print so I got one off of Ebay. The sound there was (I thought, at the moment) quite good, very open & spacious, the low-end was full with good weight, everything was well detailed.so I thought. When my copy of Patriot Games arrived I put it on and HOLY ****!!!! It was immediately apparent how much that $15K+ system at Holms Audio WAS NOT REPRODUCING! But the memory of that system remained intact, and I suspect its due to the Grommes amps. They had that old classic tube sound, which IMHO, is a very colored sound, a better than live kind of sound, very pleasant to listen to, but certainly not accurate (IMO). And then I recently found out the company has been around since 1946, and theyre headquartered in my backyard! I thought it kind of strange I never heard of them. So I just thought Id ask. Thanks! Quote Link to comment Share on other sites More sharing options...
blindman Posted January 28, 2005 Share Posted January 28, 2005 Credit to http://www.triodeel.com/eeghkh.htm Grommes 215-BA This is neat adaptation of the standard Williamson circuit with a push-pull feedback loop and a cathode follower driver circuit with a very low output impedance. The driver circuit has enough "punch" to drive tubes that need a wide voltage swing (i.e. 2A3, 300B, or 211A), and low enough output impedance to drive multiple pairs of beam tetrodes (such as 6L6 or 6550). By increasing the supply voltage for the second 6SN7 (one idea would be to use a choke in place of the 10K dropping resistor shown) and/or using multiple 6SN7's in parallel in place of the single 6SN7 cathode follower shown, even greater voltage swing and/or lower output impdence could be achieved. Different bias voltages can be had by changing the values of the 10K and 20K resistors connected between the anodes of the 6X5GT and ground. Variable bias can be had by installing a control (10K or 22K would work) between these two resistors. More negative bias can be generated by reducing the value of the 68K resistor hooked to the 6X5GT cathode. Several other types of rectifier tube (6CA4, 6X4, 6V4) or a silicon diode could be used in place of the 6X5GT. The values of the 10 uF and 20 uF filter capacitors could be increased considerably. The .1 uF capacitors between the third 6SN7 and the 807's could be increased to .22 or .47 uF. Note that the grounded tap of the output transformer secondary is the 8 ohm tap. This amplifier uses a certian amount of positive as well as negative feedback in order to increase damping factor. A standard feedback arrangement can be had by connecting the zero (common) lead to ground instead of the 8 ohm tap, then omitting the 3.3K resistor between the common and the first 6SN7, and omitting or jumpering out one of the 1K resistors between the cathode and ground of the first section of the first 6SN7. Grommes 260-A Transformers Required: Power, 274-BX. Output, 1650K (screen taps not used). Choke, 157R. This is another variation on the Mullard long-tail pair theme, this one with a cascoded triode front end in lieu of the usual EF86. A single 5AR4 tube should be used instead of the dual 5U4-GB tubes shown (unless you have a power transformer with a 5 volt, 6 amp secondary!) The 274-BX transformer specified does not have a bias tap. Any small transformer supplying between 105 to 125 volts AC may be used in place of the tap. The bias-regulator circuit is very simple and effective and may be adapted to other amplifiers. It is possible to substitute a 0C3 gas VR tube bypassed by a 47K 1 watt resistor in place of the 6L6-GB tube shown, you may want to try it both ways. The damping factor control ( a dual 1 ohm 5 watt part which is hard to find) and the adjacent .5 ohm and 2200 ohm resistors may be omitted, in fact later models did omit these parts. The output stage may be wired as triode or ultralinear (screen-tap) connection, while the 1650K transformer will work we suggest using at 1650N instead. More bias voltage (45-55 V) will be required in those cases, in a few cases you may have to reduce the value of the 22K resistor attached to the 0B2 tube to get enough negative voltage to keep the output tube current within spec (70 ma per tube for 6550, 50 ma per tube for 6CA7/EL34). Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 29, 2005 Share Posted January 29, 2005 ---------------- On 1/28/2005 11:41:30 AM sunnysal wrote: gramas....you forgot to mention how they sounded...LOL! tony ---------------- I have only heard a handful of their stuff so my thoughts are pretty worthless when it come to gromes, but i would fully back holm audio 100%, they are all great guys sell good products and they let you demo stuf with out paying for it Quote Link to comment Share on other sites More sharing options...
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