mwl168

Cold and snowy day in Minnesota. A good day to stay home and enjoy some music. The Blue Hawaii with Brimar-branded Mullard XF2 EL34 is sounding mighty good!

I have a bunch of the obsolete 2SC1815 on hand. I can send some to you if you decide to build it ?

I am relieved?

For a long time back in the 70's and 80's, KEF was also the major driver supplier for many of the highly regarded speaker manufacturers. I still remember the first time I heard the KEF 104ab in the store playing some violin recording, possibly driven by Audio Research amps. That moment for me in HiFi was akin to the first time I sit in an Alfa Romeo Giulietta in a show room. It changed me!

Resurrecting this 10 years old thread looking for recommendation for a BD\DVD player that's worthy of an OLED TV without breaking the bank. Really hope to stay below $500 US since it's not likely to get enough use to justify spending more. I only care about the video quality. Took a quick look around the web and there are plenty of players under $250 that support 4K, UHD and HDR. Wonder how much difference one can expect in terms of the video quality compare to those players costing over $1K.

My eyes are fine for things that are more than 8 feet or so away (knock on woods). Not what they used to be but when I watch those OLED TVs in the store I can still appreciate what sets them apart from the other TVs. I have been keeping an eye on this thread and seems like a few fellow casers have bought OLED TV back in 2017 and at least a couple had already reported issues. Hence my inquiry for owners experience, etc.. I own and like LG products but was always a Sony loyal back in the CRT TV days. This adds to my dilemma as the Sony OLED seems to be a fair bit more expensive than the comparable LG models.

My 65" Sharp Aquos looks to be on its last leg. It was one of the first LED-backlit models that came out. I got more than 8 years out of it which is better than what I got from my previous Mitsubishi and Pioneer combined so I am not too disappointed. Now the question is if to spend the big bucks on an OLED TV? My rule of thumb for TV goes along with the Wall Street philosophy - the next one needs to be bigger than the current one (well, at least no smaller) ? A 65" OLED costs more than twice that of an equivalent LED-backlit from the same manufacturer. I love the beautiful picture of an OLED TV but do worry about the burn-in and longevity issues. I love to hear your thoughts/experience especially from those who own or have owned OLED TVs. Thanks!

The regulated output voltage is: for V+: ((R8 + R7) / R7) x 10 (reference voltage of D5 - LT1021-10) for V-: ((R9 + R10) / R10) x 10 (reference voltage of D7 - LT1021-10) On the goldenreference4 board silkscreen, R7, R8, R9 R10 are all 1.5K. R7 and R8 are connected and R9 and R10 are connected. R8 and R9 are the 1.5K resistors closer to the DN2540 on each side of the board. The 10R is for ground connection ( from iec input ground to power suppy ground) and is optional. I personally never populated it on all the GRLV I've built.

JoaMat: I want to be clear. In my case, a calculated rectified pre-reg voltage of 460VDC was not able to sustain the desired 425VDC regulated output with my GRHV when the load is more than 100mA per rail. For my Megatron build, I used a trafo with 350v secondaries to get regulated 425VDC rails from the GRHV under load. So, depending on the load, a calculated 30 - 40 VDC drop out voltage may or may not be enough with the GRHV.

This reminded me of an exercise/experiment I went through with mypasswordis (we also consulted with Kerry) two years ago. I was hoping to figure out what's the highest, stable regulated voltage I can get from the GRHV with the Antek transformer I was using (300VA/325v rated). The short answer is that it's very load-dependent. See the measured data I copied from my PMs with mypasswordis. The GRHV was setup to deliver 426VDC rails when these measurements were taken. We never got to the bottom of this whole thing but I ultimately return my GRHV to regulate to 400VDC rails. Notice the pre-reg voltage is quite low when the power supply is loaded. This is the part that still confuses me. Maybe mypasswordis, Kerry and others will chime in. secondary ac (Antek 300VA/325v) pre-reg V at bleeder resistor regulated output current draw No load 332v/332v +461V/-461V +426V/-426V HV Carbon 326v/326v +431V/-430V +426V/-425V 97mA/101mA Blue Hawaii 318v/316v +422V/-414V +416V/-408V 81mA/147mA

Added!

No worries. This GB has dragged on for far too long. We should be back on track soon!

You can use the multimeter to identify the pinout of your amp first and go on the net and either try finding the information of the base station or ask for help from existing owners of the device. l have no knowledge of the Headroom product but if the DPS and the Base Station are different models that serve the same basic functions, it seems logical the pinout should be consistent between the two. Just a guess!

Added.

May also want to check the current rating of the PSU to make sure it can support the current draw of the GL2 amp.

To clarify, you are listed for 6 GRHV79xxx now. Do you like to add 4 more or change from 6x to 4x?

Agreed! Heard the MBL's more than 10 years ago in a store in Wisconsin Rapids following auditioning of a pair of top-end Audio Physics speakers (don't remember if it was the Medea or the Caldera now). When the MBL started playing, I did not want to think HiFi and all the stuff, I just wanted to lay back in the chair and enjoy the music!

I am also back using E180CC (Philips SQ) now for the gain tubes. Tried a pair of 6414 tubes following the Genalex 12AT7 (labelled A2900). I have yet to try the Telefunken ECC801S, Mullard CV4024 and 7316. So far I liked the Genalex A2900 and Siemens ECC801S best overall for the gain tubes. I also heard an improvement when I replaced the Tele 12AX7 with Brimar CV4004 for the driver tubes but the difference is not nearly as significant as changing the gain tubes. It may also be due to the fact that the Tele 12AX7 I was using are used tubes with unknown mileage. Just my 2 cents worth and should be taken with a large grain of salt - I was merely experimenting and most of the tubes used were NOS with only a few hours running.

The JJ KT77 datasheet states the tube as an "A. F. beam pentode" and shows a drawing of internal construction that looks like a pentode with the third grid internally connected to the cathode. But the base connection diagram shows pin 1 and 6 as not connected. Both the current and old production Genalex KT77 datasheets state the tube as a "beam tetrode" and the base connection diagram shows pin 1 and 6 as not connected just like the JJ KT77. There is no drawing of internal structure on either datasheet. Every thing I have read so far on the web refer to KT77 as a tetrode constructed similar to a 6L6. The JJ 6CA7 datasheet on the other hand has internal structure drawing of a pentode with the third grid connected to pin 1 and states the tube as an "A. F. output pentode". Yet the photo of the actual tube is a "fat boy" type big bottle similar to the Sylvania, GE and EH 6CA7 which are all true tetrode. You got to love this tube business...

Very glad to know you are doing fine now. You got the drug and rock'n roll, only one thing missing ...

There are some friends that are more helpful than others...

^ that. I think I may have a spare board laying around somewhere...?

It's winter time again - the prime time to bring out this space heater. I have forgotten how glorious this amp sounds and am reminded again how much tube choices affect the sound of this all-tube circuit - especially the front end tubes.

Thanks 老外！I’ve read your posts on this subject and was hoping you would chime in when I started this thread. Care to fathom a guess/theory why Justin advised against using KT77 on his BH amps? I recalled Kevin tried KT77 in his BH way back in 2007 but later in a PM said that KT77 is unstable at 800V +. 新年快樂！

Nice green LED power indicators - must mean both channels are on!