Deang Posted August 15, 2003 Share Posted August 15, 2003 Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted August 15, 2003 Share Posted August 15, 2003 The 5687 is a great little tube of very uniform performance across brands. I love the sound of the tube in the Horus. The Pantheon employs, of course, the 6SN7, and with the right selection of NOS tubes, works wonderfully. The 6SN7 can be a very musical tube. I would be very interested to hear Jeff's thought on using the 5687 in a pre-amp configuration. Sounds like a fine idea. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted August 15, 2003 Share Posted August 15, 2003 ---------------- On 8/15/2003 11:02:13 AM Chris Robinson wrote: The 5687 is a great little tube of very uniform performance across brands. I love the sound of the tube in the Horus. The Pantheon employs, of course, the 6SN7, and with the right selection of NOS tubes, works wonderfully. The 6SN7 can be a very musical tube. I would be very interested to hear Jeff's thought on using the 5687 in a pre-amp configuration. Sounds like a fine idea. ---------------- It should be really nice. Actually there are some preamp out there using the 5687, Audio Note preamps and the Arthur Loesch preamp come in mind. Pat's Ultimate preamp has been done quite often by DIYers and a Google search should reveal "success stories" for the most part. In this particular preamp, the volume is located after the the 5687 instead of before like on the Pantheon preamp. I really like the 5687 (low cost and no big sonic differences between brands). Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted August 15, 2003 Share Posted August 15, 2003 Jeff, our mutual friend Erik will most likely build his own pre-amp this fall as well. What would you recommend ... a Pantheon-type design or something like the above? Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted August 15, 2003 Share Posted August 15, 2003 ---------------- On 8/15/2003 1:44:51 PM Chris Robinson wrote: Jeff, our mutual friend Erik will most likely build his own pre-amp this fall as well. What would you recommend ... a Pantheon-type design or something like the above? ---------------- Hard to say what I'd recommend as there is a lot to consider. For sure the 6SN7 is a classic preamp tube and have a lot of die hard devotee. ***Warning*** (semi-boring technical stuff ahead) The SRPP is a bit demanding for the tubes if you use one tube for each channel. The top triode unit will see a much higher heater to cathode voltage that the bottom triode unit. I would trust a bit better the 6SN7 to be able to withstand this difference in the heater-to-cathode voltage between the two triode units. The 5687 may have problems with this while the 6SN7 won't really bother. So assuming the preamp will use only two tubes I'd go for a 6SN7 (beside, with the price the better 6SN7 are going for, you don't want to use 4 when you can you two). If I built it for me, I'd use four tubes and would be using the 5687 as I have a soft spot for this tube. This way I would be using only one triode unit per tube hence not having the different heater to cathode voltage difference between the units. This is something I'll eventualy end up to do in my preamp when I'll feel willing enough. Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted August 15, 2003 Share Posted August 15, 2003 ---------------- If I built it for me, I'd use four tubes and would be using the 5687 as I have a soft spot for this tube. This way I would be using only one triode unit per tube hence not having the different heater to cathode voltage difference between the units. This is something I'll eventualy end up to do in my preamp when I'll feel willing enough. ---------------- Thanks Jeff, I'll pass this on to Eric (misspelled Eric in the first iteration, not to be confused with Erik M) ... Four tubes might be interesting. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted August 15, 2003 Share Posted August 15, 2003 What I don't understand is the 5uF 5uF 20uF 20uF all ran in paralell with each other ? Also isn't that right in the signal path ? Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted August 15, 2003 Share Posted August 15, 2003 ---------------- On 8/15/2003 3:16:57 PM NOSValves wrote: What I don't understand is the 5uF 5uF 20uF 20uF all ran in paralell with each other ? Also isn't that right in the signal path ? ---------------- Running caps in // will allow you to use exotic stuff like teflon in the small values in reducing the caps resultant ESR. The french school of DIYers is pretty hot on that. I personally don't like huge // cap bank jobies so I'd use a 47 UF cap bypassed (or not) by something like a tin in foil cap. Yes it's in the signal path as it is the coupling cap. Might use IT coupling too but it's more expensive. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted August 15, 2003 Share Posted August 15, 2003 ---------------- It is kind of stupid, isn't it? He may have figured that parallel capacitors would result in a lower ESR value than using a single 50 uF capacitor. Yes, the capacitor is in the signal path. Look where the output is taken from (cathode). Before you can use the output signal, the DC component must be removed, this is the purpose of the parallel electrolytic capacitors. Then all you have is the amplified AC audio signal. I personally would have used a 100 uF capacitor bypassed with an 0.1 uF Mylar (to form a composite capacitor). By bypassing the electrolytic with a small value non-polarized capacitor, high frequency response will be improved (15KC and up). -Ryan ---------------- I'd stay quite clear of an electrolytic as coupling cap (even bypassed). I don't have much "dogmas" but this is definitively one. Quote Link to comment Share on other sites More sharing options...
Deang Posted August 15, 2003 Author Share Posted August 15, 2003 OTOH, some of the Blackgates have ESR and dissipation factors as low as some film and foils, and lower than some metallized polypropylenes. In speaker crossovers, the Blackgate AC caps are reportedly offering a smoother sound than the Hovlands. Quote Link to comment Share on other sites More sharing options...
AnalOg Posted August 15, 2003 Share Posted August 15, 2003 Excuse my ignorance, I'm still trying to grasp the read, "Reading Schematics for Dummies", but is that just one tube for the whole signal path, if so then I'm to assume its the simplicity of this design that makes it so unique. Please correct me if I'm wrong, and help me to understand this schematic. Thankx Guys, Tom Quote Link to comment Share on other sites More sharing options...
AnalOg Posted August 15, 2003 Share Posted August 15, 2003 Hey, and I just realised, no volume control & on off function, wheres the AC coming in, transformer specs? I better quit while I'm ahead. Tom Quote Link to comment Share on other sites More sharing options...
AnalOg Posted August 15, 2003 Share Posted August 15, 2003 Boy now I really look stupid, no POWER SUPPLY, thankx Ryan. Tom Quote Link to comment Share on other sites More sharing options...
mike stehr Posted August 15, 2003 Share Posted August 15, 2003 ---------------- On 8/15/2003 4:55:47 PM Inman Amplification wrote: Nothing else sounds like good old oil capacitors. -Ryan ---------------- Yep. And they can be had for fairly cheap. They are not sonically on par with Black Gate or a Elna Cerafine PS caps, but are good enough for poor mortal bastards. What's wrong with a good old school 6J5? It's a single triode octal. Quote Link to comment Share on other sites More sharing options...
AnalOg Posted August 15, 2003 Share Posted August 15, 2003 Ryan, As you can see from my sig. I built the Foreplay with all the mods & put in Hovland coupling caps, its a very sweet little line stage for the price. It is doing full duty at this point do to a problem with the Rogue. Lets just say I ain't missin the Rogue. Thankx for the offer, but my next DIY project will be a custom set of mono blocks based on the Dynaco Mark III circuitry with a cost no object parts compliment. I love the sound of the KT88, I wanna turn it up a couple of notches. Tom Quote Link to comment Share on other sites More sharing options...
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