[petewebb]

Hi All,

I got my 8900 all assembled and have been burning it in for a few weeks at this point. I absolutely love it. The build itself was pretty smooth. The only issues I had were that crazy “L” shaped joint connecting unit-4 to the speaker terminal board, OMG what a pain to solder until I discovered I could use alligator clips to keep the pins in place while I soldered them. Also unfortunately had a manufacturing issue with the chassis itself, where the front half of the chassis was ben inward toward the middle of the unit and the volume board and front faceplate wouldn't fit properly, but Victor was kind enough to swap it out for me and all fits fine now.

Things I added to the build:

• Replaced 100uF and 47uF electrolytic caps with AudioNote standards, and the 6800uF with Nichicon KA’s
• Used Z-foil naked resistors for most of the cathode, headphones and NFB positions. For the 2x signal amplification resistors and the 2x 15uF positions I used AudioNote Niobium Non-Magnetic resistors. AutoNote standard for the rest of the 220Ks. Thankfully I was able to take advantage of holiday sales.
• Used Ohmite AGs 270uF 5w resistors. Started off with Kiwame’s but switched them out as I’ve heard good things about the Ohmite AG series.
• Started off using the VCap CuTF caps I got from victor but switched them out for Duelund 0.1uF 630Vdc CAST-PIO-Ag's and had to custom rig with heat-resistant zip ties and pads, silver wire and WAGO lever nuts(so I can take the board out if needed).
• Used pure silver wire to connect volume PCB to the mainboard. (thanks for the tip Whitigir)
• I used Mundorf silver/gold solder for all the audio path components, but honestly, that stuff is a huge PITA and I would rather saw my own arm off than use it again. It’s nearly impossible to get a shiny proper joint with that stuff at any heat setting. The WBT silver/lead stuff is so much easier to use.

After I completed the main build, all the LEDs came green on the first try, which was a relief. I’ve been burning in the unit for just over 75hours now with 2A3s and 12AU7s, with some periods of listening with WE300B and 12BH7As with NFB on and off. I think I prefer the non-NFB mode and the 12BH7As, but still haven’t made up my mind between the 2A3s and WB300B (they both sound awesome).

Overall I’m super happy with the TU-8900. It was a pleasure to build and sound is out of this world. Much different than my Mainline for sure. Now I’m just waiting for Jensen JT-11P-1’s to come back in stock, and I’ll try the balanced XLR input mod.

In the meantime, I got ahold of a completely original and in great shape Dynaco ST-70 from the original owner. Starting the super fun research into restoring and upgrading it. This DIY stuff is definitely addictive!

 

[HiGHFLYiN9]

Very cool Pete, congrats on all the fun upgrades. Be careful with the Dynaco, that is a HUGE rabbit hole with more mods than you can count If you need spare parts reach out to Kevin at Dynakit Parts. All of his stuff is immaculately made.

 

[hikaru12]

Poured through this thread - seems like Elekit offers a lot of flexibility especially considering the case size on cap upgrades, etc. Has anyone ever compared it to the ZMF Pendant?

 

[HiGHFLYiN9]

ZMF Pendant uses indirectly heated EL84 tubes so the harmonics are going to be quite different. EL84s amps are generally pretty crisp and detailed sounding. I still have my Budgie SE so I could compare that when the 8900 is done. The ZMF has a rectifier tube and probably other tweaks, but I believe the circuit is similar. On paper DHTs are inferior although most tube enthusiasts like the additional "tubiness" that they bring to the table. They are expensive, microphonic, and usually require further efforts to reduce noise within the circuit, but they are more syrupy and warm sounding. A better indirectly heated tube to compare to the 300B is the EL34 which has a similar midrange "magic" imho. Unfortunately there are few EL34 based headphone amps, however there are many EL84 amps, I'd assume because two EL84s can handle very adequate power for most headphones.

If you like the DIY route, Audio Note Kits has an EL84 based headphone amplifier and you get really good parts for your money: https://ankaudiokits.com/product/headphone-virtuoso-el84/ ...Brian is friendly and very responsive although it can sometimes take him a bit to get you all the parts for the build. Many of the premium parts people are upgrading here come standard with the Virtuoso. I'd personally buy one but I need another amp like I need a hole in the head

For whatever it's worth, and to be taken with much salt as everyone has different preferences, but the best system I ever heard was powered by 300Bs.

 

[Maven86]

Hi All,

I got my 8900 all assembled and have been burning it in for a few weeks at this point. I absolutely love it. The build itself was pretty smooth. The only issues I had were that crazy “L” shaped joint connecting unit-4 to the speaker terminal board, OMG what a pain to solder until I discovered I could use alligator clips to keep the pins in place while I soldered them. Also unfortunately had a manufacturing issue with the chassis itself, where the front half of the chassis was ben inward toward the middle of the unit and the volume board and front faceplate wouldn't fit properly, but Victor was kind enough to swap it out for me and all fits fine now.

Things I added to the build:

• Replaced 100uF and 47uF electrolytic caps with AudioNote standards, and the 6800uF with Nichicon KA’s
• Used Z-foil naked resistors for most of the cathode, headphones and NFB positions. For the 2x signal amplification resistors and the 2x 15uF positions I used AudioNote Niobium Non-Magnetic resistors. AutoNote standard for the rest of the 220Ks. Thankfully I was able to take advantage of holiday sales.
• Used Ohmite AGs 270uF 5w resistors. Started off with Kiwame’s but switched them out as I’ve heard good things about the Ohmite AG series.
• Started off using the VCap CuTF caps I got from victor but switched them out for Duelund 0.1uF 630Vdc CAST-PIO-Ag's and had to custom rig with heat-resistant zip ties and pads, silver wire and WAGO lever nuts(so I can take the board out if needed).
• Used pure silver wire to connect volume PCB to the mainboard. (thanks for the tip Whitigir)
• I used Mundorf silver/gold solder for all the audio path components, but honestly, that stuff is a huge PITA and I would rather saw my own arm off than use it again. It’s nearly impossible to get a shiny proper joint with that stuff at any heat setting. The WBT silver/lead stuff is so much easier to use.

After I completed the main build, all the LEDs came green on the first try, which was a relief. I’ve been burning in the unit for just over 75hours now with 2A3s and 12AU7s, with some periods of listening with WE300B and 12BH7As with NFB on and off. I think I prefer the non-NFB mode and the 12BH7As, but still haven’t made up my mind between the 2A3s and WB300B (they both sound awesome).

Overall I’m super happy with the TU-8900. It was a pleasure to build and sound is out of this world. Much different than my Mainline for sure. Now I’m just waiting for Jensen JT-11P-1’s to come back in stock, and I’ll try the balanced XLR input mod.

In the meantime, I got ahold of a completely original and in great shape Dynaco ST-70 from the original owner. Starting the super fun research into restoring and upgrading it. This DIY stuff is definitely addictive!

Wow... That's probably the most tricked out Elekit I've seen so far. How was the switch from the V-Caps to the Duelund? Was always curious to compare the two but didn't want to deal with the hassle of another week long burn in.

 

[JamieMcC]

Where are you guys sourcing your 0.1uf AG Duelunds?

 

[petewebb]

Wow... That's probably the most tricked out Elekit I've seen so far. How was the switch from the V-Caps to the Duelund? Was always curious to compare the two but didn't want to deal with the hassle of another week long burn in.

So far I only have about 25hrs on the Duelunds, and they sound a bit more neutral than the V-Caps. My setup is already pretty neutral sounding due to the Z-Foil resistors I used. I'm going to switch the caps around again this weekend, so I'll let you know.

 

[petewebb]

Where are you guys sourcing your 0.1uf AG Duelunds?

Got mine at Partsconnexion: https://www.partsconnexion.com/duel-cast-au630v.html

 

[Maven86]

Where are you guys sourcing your 0.1uf AG Duelunds?

Private sales and partsconnexion when on sale. If you're in the UK I think Hificollective might be better:

https://www.hificollective.co.uk/catalog/castdcag010-01uf-630v-duelund-cast-silver-stock-p-9417.html

 

[hikaru12]

So can any of you guys build me a kit? There’s a guy on Etsy who will do it for $500 but don’t know if that’s a fair price given the relative simplicity in putting this together. I just suck at soldering lol

 

[jamato8]

So can any of you guys build me a kit? There’s a guy on Etsy who will do it for $500 but don’t know if that’s a fair price given the relative simplicity in putting this together. I just suck at soldering lol

Seems high to me. I don't remember the house to build but say 8 hours, and I think it is less, at 50 dollars an hour that would be 400. Seems it could be less. Maybe the company that sells the kit also will do a build. I think I read they do and then everything would be tested for you as well.

 

[Maven86]

So can any of you guys build me a kit? There’s a guy on Etsy who will do it for $500 but don’t know if that’s a fair price given the relative simplicity in putting this together. I just suck at soldering lol

Try contacting Victor, I believe he’s building kits for a few people now.

 

[HiGHFLYiN9]

So can any of you guys build me a kit? There’s a guy on Etsy who will do it for $500 but don’t know if that’s a fair price given the relative simplicity in putting this together. I just suck at soldering lol

Is that the guy that builds Bottlehead kits?

It's going to be somewhat dependent on where you live and the cost of living. An experienced professional costs about as much as a mechanic. Here in the DMV area the cost for a solder slinger/amp repair is about $45-90 an hour depending on experience and may have a minimum "bench" fee. You may be able to find someone that can do it for less in their basement, but make sure they have some feedback!

Also, does anyone have a digital copy of the BoM? I wanted to look it over. Viktor is waiting on some VCaps before my order can ship.

So far I only have about 25hrs on the Duelunds, and they sound a bit more neutral than the V-Caps. My setup is already pretty neutral sounding due to the Z-Foil resistors I used. I'm going to switch the caps around again this weekend, so I'll let you know.

Pete those V-Caps can take 500 hours to settle in, so make sure to give them a fair shake before settling with the Duelund. Both are obviously very good caps though.

 

[petewebb]

Is that the guy that builds Bottlehead kits?

It's going to be somewhat dependent on where you live and the cost of living. An experienced professional costs about as much as a mechanic. Here in the DMV area the cost for a solder slinger/amp repair is about $45-90 an hour depending on experience and may have a minimum "bench" fee. You may be able to find someone that can do it for less in their basement, but make sure they have some feedback!

Also, does anyone have a digital copy of the BoM? I wanted to look it over. Viktor is waiting on some VCaps before my order can ship.


Pete those V-Caps can take 500 hours to settle in, so make sure to give them a fair shake before settling with the Duelund. Both are obviously very good caps though.

I'll DM you the BoM.

I'll definitely give the V-Caps more time. I accidentally bought 2 sets of them (one from victor and one directly). I was thinking of putting the spare set in the Mainline in place of the .1uFs there but I don't think it would do anything but make the underside of the chassis more pretty.

 

[JamieMcC]

I'll DM you the BoM.

I'll definitely give the V-Caps more time. I accidentally bought 2 sets of them (one from victor and one directly). I was thinking of putting the spare set in the Mainline in place of the .1uFs there but I don't think it would do anything but make the underside of the chassis more pretty.

Fwiw on my own Mainline which I built in 2015 I had installed RTI 10uf tin foil teflons for the output capacitors. In 2020 I thought I would give the 0.01 Duelund silver foil bypass caps a go. I was expecting some small improvement but in all honesty the silver foil Duelund bypass caps made the largest step change in sonics I've ever experienced in installing a capacitor.

I have since transplanted them onto the Vcap cutf in my TU-8900

I would echo the requirement for 400-500 hrs of burn in with the Vcaps and the AM transformers.

Both the Cossor WE2A3 & WE300B tubes purchased new from Victor with the amp took about 100hrs before settling down and coming on song.