nikongod

A thread to post photos of our dogs. Behold! Freddy! He is a Bichion-spaniel mutt we adopted when he was about 1 year old. As far as I can tell Im not allergic to him.

I dont think its necessarily the transformers, but the ways feedback is applied around the output stage and its driver, and the "unconventional" coupling network between the gain and driver stage. There are far worse things out there than transformers. so there are 2 separate circuits on the board where all the parts are doubled up? 2 rectifiers, 2 big power resistors, 2 big electrolytic caps, and 2 small films?

take a DMM, unplug the cable and measure all the connections. Every pin at the top should hook up to something at the bottom. or you could just plug the plugs into the headphone backwards. Thats the plug that says "R" in the earpiece which has the braile letter "L" as well as the letter "L". If the noiseless channel moves taah-daah! my bet is on the cord being defunct.

Have a Happy Birthday!

Happy Birthday! keep the tubes hot

I agree with the recommendations for transformer coupled tube amps and the RS-1 although I dont have much experience with the ones mentioned here. SET means that there is only 1 triode per active stage, and is independent of whether they are directly or indirectly heated. The DNA amp is SET for sure, with only 1 triode per channel.

happy birthday!~

AC heaters. Bias them 75V above ground. Tubes that hum with "biased" AC heaters are not worth using in an amp 1/8 as expensive as this one. People like to blame the amp when tubes hum with AC heaters, and you know MFR's NEVER like to use AC for this reason. The old hum-bottles some dude had that never ran noisy on DC are now noisy on AC heaters (durr) any hum is bad, and these tubes have been in his family for generations: his grandfather built them and smuggled them into the country! How could they be anything but great? The cheap SET amp with no global feedback he just bought hums like whoa with his priceless communist tubes. Its terrible customer service to tell these people that any of their gear is crap, save the phone call and complaint thread on the web, spend $5 on a rectifier and a cap, and use DC heaters. Whether DC heaters are any better with tubes that dont hum is of course a topic of long heated threads all over the place, but you have to be truly special to make DC heaters hum and thats all that matters when your trying to make a buck. The darkvoice threads on head-fi are great examples of this: my amp hums with some tubes but not others. Why does my amp suck? Its your tubes (OK darkvoice grounds their heaters which dosnt help the situation at all), but nobody wants to hear that because they were expensive NOS tubes.... The new design is an ACTIVE regulator with some feedback built in to get low output impedance, where the old one was either a source follower/capacitance multiplier or a shunt based regulator. The schematic KG posted up is 100% tube which I also think was the intent of the original PS, except his schematic is like 10milion times nicer on the patrick82 scale than even my optimistic guesses of whats in there. It means that the adjustments to voltage are no longer done in steps. Rather than what amounts to a "high/medium/low" switch you have a knob that goes from low to OMFGWTFBBQ!!!111 without steps. Unless Im mistaken you can also adjust voltage while the amp is on with this setup (cool as hell!). As far as the dual pot thingy, you have to find a pot like what is sometimes used for EQ controls for separte channels on cheap stereo amps: no biggie. They are abundant in old junk gear. You could also just use 2 totally separate knobs/pots. On that note, Im not sure that separate *adjustable* regulators for Gain and output are a GREAT idea unless care is taken to limit the range (and then why even bother?) for the regulator for the gain tubes. I can see hardcore failures if the plate voltage on the gain tubes comes up higher than B+ on the output tubes, or when the same plate voltage sets the idle current for the output stage unsafely high for 6sn7. Why not use something like this: The PS KG drew up, with the lower limit of voltage at 340V with a simple SS regulator LOCKED IN at 320V (or whatever mikhail used in your amp and 20V more from the tube regulators to the output stage, my numbers as example) fed off of KG's regulator. The whole mess could be built dual-mono and would never have the risks of funky/incompatible voltages outlined above. This adds some silicon to the circuit as a regulator, but its somewhat protected by the tube ( LOL ) AND makes the current draw from both regulators identical. with separate regulators for output & gain you have one regulating 20mA and one regulating 50-80mA. This would light up at 30-60ma per regulator (same current on both regulators, variance is the use of different output tubes ) no mater what.

happy birthday!

happy birthday!

happy birthday

I think from previous descriptions that this PS is more of a simple shunt regulator without any SS followers. Perhaps something was lost in translation, but time will tell as this box gets cracked. something like this: The thing could totally run a WCF depending how the resistor is sized, but I have read that getting a tube-based shunt regulator to "light" can be quite the trick, and I cant imagine it being any easier considering that different combinations of audio tubes will draw different amounts of current in the amp. The first time I read about the photo-flash trick, I thought that someone had wired the electronics from a photo-flash (or something like it) into the PS to bitch-slap the tubes into operation. LOL

The pinouts are different. The ECC-1 adapter is for 12a?7 tubes. 6cg7 had its own adapter.

Im going on previous statements.

The 12ax7 to 6sl7 and 12au7 to 6sn7 adapters are likely the same. Return some if you can. If you have a multimeter, verify that none of the connections have resistors (they probably dont) and then your set. Nope, not an exact swap. 12AT7 may be a close enough approximation to the 6sl7. Bonus round, it uses the same adapter as the others above. OTOH, the ZD uses a bunch of global feedback, the funky capacatances of the adapter may interfere and cause "funk." Its a mater of riding on tolerances. Some combinations are downright weird and stressful with how they run the tubes. Others are simply making use of the same tube in a different bottle, or with different pins. some other options use big ass power tubes loafing along under very low loads. ECC-1 wired straight through. 5687: has some extra resistance on the cathode of 1 section so they dont draw tooooo much current in the output stage. I dont know if there are "speshul" 5687 adapters for the ES-1 with resistors on BOTH cathodes or no resistors. Im also not aware of anyone but mikhail building this adapter. Others: no idea you can tell in about 2 min with a multimeter and pin-out diagrams though.

this SUCKS. I hope you can find someone locally to work on this amp.

happy birthday dave!

i dont go to the slow forum.

Gizmodo - Beautiful Women and Headphones: Oil Paintings by Jonathan Viner (NSFW) - Jonathan viner NOTE! link may be NSFW!

lolerskates and got a link?

Gott ist taub - Nietzsche

I thought it was a bad idea because the rest of the pre has gone to such great lengths to use no SS parts anywhere. Tube rectifier, pentode voltage regulator,, the whole thing is grid biased (even the phono-stage). The only silicon is in the heater & biassing supply. For sure the CCS would improve PSRR/SNR, linearity, and bump the gain, but I think its cool having an amp with no SS parts anywhere. I guess my opinion is more philosophical than scientific.

I have heard an older Gilmore G22/22 next to a FET-A at a mini-meet at davederek's (head-fi handle) house and someone else whose name I forgot. For point of reference, the source for the dynamics was the Musical Fidelity A5 which has never let me down at mini-meets at Dave's house. The overall sound of wire with gain was running full tilt with the Gilmore, dunno what else to say about it that hasn

It also decreases the inductance of the wire. Speaker guys do it because the little bit of "accidental" inductance from the cables screws with their crossovers.

I took a moment to listen to this amp and chat with Donald North at the national meet. The amp was quite nice. I didnt listen nearly as long as I would have liked, but it did quite well for detial and tonal balance with DT-880/250. The IEC output takes the DT-880 to a new level, and makes them a very strong point for price VS performance. Chatting with DN was great, and I listened to a CD that I would not have otherwise thought to get. I didnt press him for the specs of his transformers, but still hold my previously stated guesses. We chatted about amps in general and he certainly knows his stuff!