[leftside]

I shouldn't have hesitated, someone beat me to this nice pair of Tele's. The seller is a Head-Fier, I PM'd him to see if I could save him eBay fees, too slow

https://www.ebay.com/itm/114270259204

I am bidding on these Valvos, you've been warned!

https://www.ebay.com/itm/313129349252

Sorry that was me! Someone sent me the link and asked if I had those boxes. But, what grabbed my attention was the included adapters - as I'm going to need those - and that made the complete package a good deal. I'm not bidding on the Valvo's!

 

[leftside]

The EL11 at least are equivalent to the EL3, with the proper adapter they should be able to be run optimally in Glenn's EL3N amp.

That was why I asked earlier. I think the main reason would be able to use the Telefunken, as I've seen plenty of Telefunken EL11, but very few Telefunken EL3N (maybe none?).

 

[L0rdGwyn]

Sorry that was me! Someone sent me the link and asked if I had those boxes. But, what grabbed my attention was the included adapters - as I'm going to need those - and that made the complete package a good deal. I'm not bidding on the Valvo's!

No worries! I'm sure another pair will show up, I'm gonna try for the Valvos.

That was why I asked earlier. I think the main reason would be able to use the Telefunken, as I've seen plenty of Telefunken EL11, but very few Telefunken EL3N (maybe none?).

Yeah they are the same tube, just different bases. All of the German-made I have seen are EL11 (Telefunken, Siemens, RFT, Valvo) and have the 8-pin Y8A base. The EL3N obviously have the side contact P8A base, then there is the EL33 which has a standard octal base. All the same tube, just different manufacturers and bases, with adapters, any of them can be subbed. I'm surprised the EL33 haven't gotten more discussion around the tube threads since they are an octal equivalent. Billington at one point had a pretty large stock of them for good prices. All of the EL33 I have seen have been Mullard / Phillips.

 

[chrisdrop]

No worries! I'm sure another pair will show up, I'm gonna try for the Valvos.

Yeah they are the same tube, just different bases. All of the German-made I have seen are EL11 (Telefunken, Siemens, RFT, Valvo) and have the 8-pin Y8A base. The EL3N obviously have the side contact P8A base, then there is the EL33 which has a standard octal base. All the same tube, just different manufacturers and bases, with adapters, any of them can be subbed. I'm surprised the EL33 haven't gotten more discussion around the tube threads since they are an octal equivalent. Billington at one point had a pretty large stock of them for good prices. All of the EL33 I have seen have been Mullard / Phillips.

This thread sent me listening to EL3Ns and EL11s yesterday (both of mine are Phillips). One of my EL3Ns is a bit noisy. Sadly so is 1 of my EL11s. Both sets are usable but it is not silent. I did go looking yesterday for EL11s too and I am glad I didn't add to the head-fi bid-off. IMO both of these are warmer, but quite spacious and a good compliment for crisper outputs.

 

[UntilThen]

Compared my different ECC32 tubes tonight. Foil, pan and D getter. The good news is if you're looking for one of these to purely listen to, and not necessarily collect, they all sound the same - well at least in my amp. The latter D getters tend to be a little cheaper than the earlier foil or pan getters. These are absolutely some of the best drivers out there. I can't think of anything I don't like about them - and the bass with this amp is superb. Spun up tonight with 4 Tungsol 5998 and a pair of Bendix 6080.

Having listened further to the various power tubes, I do think I am hearing a slight difference with the TS 5998 over the 6AS7 and 6080 family of tubes. These are my preference right now - even more than the GEC 6AS7G - in this amp. It might be because there is extra gain with the 5998. Further listening is required.... which is fine by me

Mischa, the power section runs cooler when running the 5998's and the 5998 switch engaged. I like this, but I would have expected the amp to have run warmer with this setting/tubes. Shows what I know...

That's a staggering number of good tubes together ! I can see there are 4 x Tung Sol 5998, 2 x Mullard EL38, 2 x Bendix 6080wb, 2 x Mullard EL8 and a Mullard ECC32. What are the 3 most prominent sound characteristics you can think of to describe this combination.

This is certainly one amp to beat them all in terms of flexibility of tube combinations.

 

[whirlwind]

No worries! I'm sure another pair will show up, I'm gonna try for the Valvos.



Yeah they are the same tube, just different bases. All of the German-made I have seen are EL11 (Telefunken, Siemens, RFT, Valvo) and have the 8-pin Y8A base. The EL3N obviously have the side contact P8A base, then there is the EL33 which has a standard octal base. All the same tube, just different manufacturers and bases, with adapters, any of them can be subbed. I'm surprised the EL33 haven't gotten more discussion around the tube threads since they are an octal equivalent. Billington at one point had a pretty large stock of them for good prices. All of the EL33 I have seen have been Mullard / Phillips.

I agree the EL33 has what IMO would be the best socket/pins as being the octal equivilent to the EL3N can't be a bad thing.

 

[leftside]

This thread sent me listening to EL3Ns and EL11s yesterday (both of mine are Phillips). One of my EL3Ns is a bit noisy. Sadly so is 1 of my EL11s. Both sets are usable but it is not silent. I did go looking yesterday for EL11s too and I am glad I didn't add to the head-fi bid-off. IMO both of these are warmer, but quite spacious and a good compliment for crisper outputs.

Most are noisy in my amp as well. It's probably due to the extra gain of these tubes. They are typically used in most amps as power, not driver tubes. I think this extra warmth might simply be a little distortion (which measures terribly, but can be pleasing to the human ear). They don't sound "warm" in my amp, but the bass is definitely "different".

I'll be looking for an KT66/6L6/EL3/EL34/EL37 selector switch in my next amp if possible/reasonable. @A2029 thinks "oh no - here we go again...."

 

[leftside]

That's a staggering number of good tubes together ! I can see there are 4 x Tung Sol 5998, 2 x Mullard EL38, 2 x Bendix 6080wb, 2 x Mullard EL8 and a Mullard ECC32. What are the 3 most prominent sound characteristics you can think of to describe this combination.

This is certainly one amp to beat them all in terms of flexibility of tube combinations.

The driver tubes are not used at the same time. The selector switch enables the circuit for the tubes selected. The TS + 2 6080 or 2 6AS7 is my favorite power combo. 6 TS is just a little "too much". Sound wise, there isn't too much difference between the various brands of power tubes due to the circuit design. I'm considering this a "good thing" (for me), as I do find sonic differences between say 76/6J5/6N7 and that's good enough.

The amp is extremely detailed, with a defined powerful bass that I've never heard from another headphone amp. I'm completely honest when I say the 6 power tubes are overkill, and Mischa ensures me he can build a cheaper and smaller amp with the same sound signature and less power tubes. The 6 driver tube selections can be seen as great flexibility or a path to madness

 

[UntilThen]

Ah I thought the EL38 were used as power tubes but in this instance you had it in the c3g sockets as drivers. Just read your 1st page and realised that you can use 4 x 6336 as power tubes. I could use that 'warmth' in the winter of Sydney now.

Have you run it with 4 x 6336 as power tubes?

 

[leftside]

Ah I thought the EL38 were used as power tubes but in this instance you had it in the c3g sockets as drivers. Just read your 1st page and realised that you can use 4 x 6336 as power tubes. I could use that 'warmth' in the winter of Sydney now.

Have you run it with 4 x 6336 as power tubes?

I don't have those tubes. I bet 4 would be nice and toasty.

 

[A2029]

NEW PRODUCT: BLUE HALO (Amplifier)

BLUE HALO is a dedicated amp for high impedance headphones such as the Sennheiser HD600/650/800, ZMF Verite/Verite C, Beyerdynamic, etc. (anything with 200+ ohm impedance). It's a design that eliminates the need for 6AS7/6080/5998 power tubes for output power. It has two 6J5 sockets and a 6SN7 socket. You can plug in a pair or 6J5, a single 6SN7, or both at the same time. With the use of adapters (purchased separately), hundreds (even thousands) of other types of tubes can be used within the sockets as well (including C3G, 12AU7, 12BH7, and many many others). A 12V switch is also included at the back of the unit in order to use 12V tubes. It produces ~1 watt into 300ohms, more than enough for all high impedance headphones.

BLUE HALO is designed to have a clean, neutral, detailed and smooth sound with great bass. Tube rolling alters the tone of the amp at your preference (e.g. warmer tubes, more detailed tubes, more mids, etc.). The tubes get "supercharged" so that they can produce as much power as 6AS7/6080 power tubes, while fully determining the tone. Not having the 6AS7/6080 tubes means one less gain stage between the input and output = More clarity. The high voltage power supply uses only high quality wax/oil filled polypropylene film caps. Output capacitor are also high quality wax/oil filled polypropylene film capacitors. This means there are zero electrolytics within the signal path - something that no other OTL tube amp has!

BLUE HALO does not use tube rectification, it uses my own custom designed circuit using critically damped and resistivily bounded HEXFRED rectification followed by a high voltage Maida style super regulator and utilizing a wax/oil polypropylene capacitor. This is a much better alternative to tube rectification as it leads to better overall tonal quality, better bass and cleaner overall tone. This also gives deeper blacks and bigger soundstage than tube rectification. It also uses regulated DC on the heaters for a silent black background and zero hum.

BLUE HALO has a base build that includes Neutrik RCA & XLR inputs, Neutrik TRS and 4pin XLR outputs, CNC Engraving, QQQ sockets, Alps Blue velvet pot, and high quality copper internal wiring.

Potential upgrade options include: Lundahl power transformer, Stepped Attenuator (e.g. Acoustic Dimension, Goldpoint, Khozmo, etc.), Kiwame power resistor upgrade, Vishay/Dale RN55/RN60 signal resistor upgrade, Supercharger capacitor upgrades, vibration isolation feet, tube socket upgrades, and RCA/XLR connector upgrades. VU Meters are also possible.

More Photos of BLUE HALO here: https://photos.app.goo.gl/yhVnwuC9Tp25vXdD8

If interested in a custom build, please contact for more details, pricing and build time.

 

[L0rdGwyn]

Looks fantastic, awesome work @A2029 looking forward to hearing impressions, maybe even laying ears on one some day!

 

[whirlwind]

Looks nice!

 

[LoryWiv]

...The tubes get "supercharged" so that they can produce as much power as 6AS7/6080 power tubes, while fully determining the tone. Not having the 6AS7/6080 tubes means one less gain stage between the input and output = More clarity. The high voltage power supply uses only high quality wax/oil filled polypropylene film caps. Output capacitor are also high quality wax/oil filled polypropylene film capacitors. This means there are zero electrolytics within the signal path - something that no other OTL tube amp has!

Really intriguing, thanks @A2029! Wondering if this design / tube implementation impacts tube lifespan or other operating characteristics.

 

[A2029]

New Product: PURE POWER C2029 (Power Conditioner + Surge Protection)

The PURE POWER C2029 is built for those looking to clean up noise from their house power lines. It has high, medium and low current outlets so that you can plug a whole audio system into the conditioner. The high current line features zero current limiting for heavy current devices (up to 15 Amps) while still offering mild line filtering. The low current outlet offers a high amount of filtering for low current devices (up to 4 Amps), and is best suited to digital devices most sensitive to line noise. Low current devices with switching power supplies can also be plugged into the low current outlet for the most decoupling of their RFI/EMI noise from the rest of the audio system. Medium current outlet offers a middle ground between filtering and un-impeded current flow (up to 8 Amps), and can sound best with medium current analog devices such as headphone amplifiers. All outlets are decoupled from each other and RC damped to reduce power line ringing during transformer pulses. All lines are triple surge protected against massive surges (up to 40 kA!!) by combinations of UltraMOVs and GDTs, all without affecting the delivery of filtered AC.

Base build uses Leviton 5262-GY outlets with nice brass backstraps and tremendous gripping force. Cheaper outlets use steel backstraps, meaning that ground currents have to run through high resistance magnetic steel. Not here I say! Further outlet upgrades are available on request. Also possible to put analog current and voltage panel meters on the front to get an indication of line voltage and current.

Here we can see the BLUE HALO amp stacked on top of the C2029 conditioner (same footprint):

The Pure Power C2029 is available as a stand alone build, or paired with the Blue Halo amplifier. If interested in a build, please contact for more details, pricing and build time.