Salas fixed the gain problem, was the 15K-300R OPT at the 26 preamp output. BTW I upgraded the Itch sound.
Hello Salas . Have finished the phono amp and I would like to thank you for the design . It is so quite compared to my other tube phono , i will be burning in for a while but I am already very happy with the sound . i ended up using what i had as far as power supply build ,which is full tube regulated . I have a few tables and am going to try a few differnt cartridges i have . Will post some pictures soon .
Congratulations. We will be seeing the photos. And some info on what table and cart combined best.
Congrats, when you can post pics, I'm interested also in the schematic of your full regulated PSU.
Sorry for delay in Photo . Have been enjoying the itch ,Have put 9hrs on the units and will be checking voltages and changing the toroid transformer for the heaters , I am running it pretty hard and it warms up further than i like 45-50 deg at a guess . tables are luxman pd 310 with technics epa100 and lyra delos .
pioneer pl 7l with audio technica at33ptg . last is all British Michell Gyro with fully rebuilt sme 3009 and Deca Super Gold . All play very well with the itch with the Deca using the mm input .
pioneer pl 7l with audio technica at33ptg . last is all British Michell Gyro with fully rebuilt sme 3009 and Deca Super Gold . All play very well with the itch with the Deca using the mm input .
Very nice. Congratulations. Can you comment about each picture? What is included in the unit with the many knobs for instance.
Are you using the Silk Audio MC step up transformers in a compartment for routing the different turntables with a switch?
See for DC offset on the direct MM Itch input. Grid current can create on the 47K load resistor. Input tubes selected samples help.
Cool vintage tables and arms there. They look in very good condition too. Do you operate the vacuum pump unit with the Lux TT?
Do you also copy vinyl the analog way? A Luxman cassette deck like this one I had around would be good company to your PD-310.
Are you using the Silk Audio MC step up transformers in a compartment for routing the different turntables with a switch?
See for DC offset on the direct MM Itch input. Grid current can create on the 47K load resistor. Input tubes selected samples help.
Cool vintage tables and arms there. They look in very good condition too. Do you operate the vacuum pump unit with the Lux TT?
Do you also copy vinyl the analog way? A Luxman cassette deck like this one I had around would be good company to your PD-310.
The way i have set it up is 5 inputs at rear , 1 set for sowter transformer used for denon MC , 3 sets for silk transformer , and 1 set MM . the external switch's are right to left , denon input resister mod , switch for 3 inputs to silk trans , switch for silk 10:1 or 20:1 , switch for mm, mc or denon , switch for input resistor 22k thru to 100k , switch for capacitance 0 thru to 390 pf . I had these adjustments in my previous phono unit , It makes changing cartridges easy , The deca likes to run on 220Pf .
I have the pump but is to noisy and the seals have to be perfect to stop it cycling to much ,
I like vintage equipment enjoy bring them back to original . The tape deck is amazing , I also have a Onkyo p308 put away .
My input tubes are 6av6 I have a collection of various makers and being a single triode 1 require 2 for each input , they are matched but mixing the brands changes the tone of the phono I am currently using GE and Telefunkun . sylvania tubes for 6sn7 s
The power supply diagram is mostly right checked and changed some minor items , the tubes are what i had the 6n2p ,6n13c and 6c5s . DC heaters made 2 they are good for 3 amps the other i had from previous project .
I have the pump but is to noisy and the seals have to be perfect to stop it cycling to much ,
I like vintage equipment enjoy bring them back to original . The tape deck is amazing , I also have a Onkyo p308 put away .
My input tubes are 6av6 I have a collection of various makers and being a single triode 1 require 2 for each input , they are matched but mixing the brands changes the tone of the phono I am currently using GE and Telefunkun . sylvania tubes for 6sn7 s
The power supply diagram is mostly right checked and changed some minor items , the tubes are what i had the 6n2p ,6n13c and 6c5s . DC heaters made 2 they are good for 3 amps the other i had from previous project .
Thanks for the info. Makes clear how you implemented your own Valve Itch. I can also see guitar amp chokes in the PSU I think.
I am happy that you like it. Have many good listening hours with it and the awesome vintage TTs, the interesting cartridges, and the various NOS valves to swap.
But watch for the gain to remain agreeable between channels when you change valve units. There's no loop feedback to fix the gain in this circuit.
It's all about the μ amplification factor achieved in the triodes. Both input and output ones. Thus their sample to sample μ spec tolerances matter.
I am happy that you like it. Have many good listening hours with it and the awesome vintage TTs, the interesting cartridges, and the various NOS valves to swap.
But watch for the gain to remain agreeable between channels when you change valve units. There's no loop feedback to fix the gain in this circuit.
It's all about the μ amplification factor achieved in the triodes. Both input and output ones. Thus their sample to sample μ spec tolerances matter.
Thanks . I am about to check all the voltages again in the Itch to make sure all is stable after 10 hrs of use . i will make sure to check the gain on both channels . I made the board that mounts the 6AV6 all plug in , I have the 6n2p eb so am going to make the original set up for the amp as a comparison , then plug it in to compare the sound . thanks again for the design and sorting work .
6N2P-ER is the best in its family. In general the Itch is versatile, all 12AX7 alike types will basically work in the input stage, the difference is in low grid current spec and good microphonic performance. By the way, what are you using for line level, power, and loudspeakers?
Have a few English 6AV6 which are very sensitive to microphonics . Rest of system is Pre amp Ming Da MC 2A3 with some minor cap changes and tube rolling , power amps are Transcendent OTL for mid and high and local made CYMER kt88 push pull mono blocks for the base . The speakers I have are rebuilt Yamaha NS1200 , base cones from NS1000 x which are carbon , original dome mid and a large Fountec ribbon for the tweeter . crossovers were rebuilt with large solen air core and caps . 2 dacs that are tube output and custom DIY built .
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