[JKDJedi]

Does the amp work with the 6AS7 tube in it??

With just one tube yes, and with both yes, just was expecting the output to get somewhat louder or comparable to one 6as7g tube, jot the case with the dual setup.

 

[L0rdGwyn]

Well I got the two Telefunken MH4 tubes today and kind of upset.
The box was to pristine it was a new reproduction box.
The tube is perfect old tube but it has nothing on it no writing at all not even the tube number.
How do I know if it is really a Telefunken? on the bottom of the base both tubes have a number 2 and under it is FL.
Does anyone know what these letters mean?

Glenn, was doing some digging on this. I think they are made by Philips in Eindhoven, Holland. Here is one that looks identical, it is an E424, which was a Philips tube, a REN904 equivalent. Same code on the bottom 2 FL. I don't think they are Telefunkens, looks like that seller had some bad info...

Still gorgeous tubes though.

https://www.ebay.com/itm/Philips-E4...Audio-Tube-Valve-Rohre-Amplifier/253958550653

 

[L0rdGwyn]

I have two General Electric 6BL7GTA (1959) and an adapter (two to one) that I'd like to give away or at least get any offers for, I've just had a fiasco of problems getting the right adapter for my Darkvoice amp (from China, from Bulgaria...nothing works ) and am throwing in the towel on this project/experiment, please take this thing away from me! I'm sure the adapter was wired for a parallel wired amp as it does not work well on mine (In series wired) PM me

That adapter was undoubtedly made by @Deyan , he might be able to help you out or get you a working replacement.

With just one tube yes, and with both yes, just was expecting the output to get somewhat louder or comparable to one 6as7g tube, jot the case with the dual setup.

Edit: oh I see, the adapter works but you were hoping for more gain. The Darkvoice is a cathode follower, so the output tubes are wired for unity gain, meaning any output tube will essentially have no gain, doesn't matter which one you use, won't get louder.

 

[JKDJedi]

That adapter was undoubtedly made by @Deyan , he might be able to help you out or get you a working replacement.



Edit: oh I see, the adapter works but you were hoping for more gain. The Darkvoice is a cathode follower, so the output tubes are wired for unity gain, meaning any output tube will essentially have no gain, doesn't matter which one you use, won't get louder.

Output tube is the 6as7g? And because of the design of the Darkvoice even if I had 8 tubes with adapter the gain will be the same, interesting.

 

[L0rdGwyn]

Output tube is the 6as7g? And because of the design of the Darkvoice even if I had 8 tubes with adapter the gain will be the same, interesting.

Yes, the output is the 6AS7G. It is a consequence of the circuit topology. If you Google "cathode follower unity gain" you can read about it.

 

[UntilThen]

Nothing. Especially this:

I had gone for less than a day and Taylor Swift has taken over the thread.

 

[UntilThen]

Thank the Gods! My prayers have been answered.

Prayers not required. Glad that is what you're looking for. Don't apply too much or it'll overflow. It will hold. It's super glue for glass.

 

[UntilThen]

Bravo @gibosi, first theoretical offering I've heard that comes closer to reality. At least the reality that some of us experience.
Have to applaud you for your clarity of thought and diligent work.

Also for daring to go where few would go. LOL, I have heard stories that in darker times, people were burned alive in the public square for suggesting that the Earth orbited around the Sun, or the Earth was round, or rectifier tubes had their own unique sound. I know, hard to believe, but it's true. Well, maybe not for rectifier heresy, we know rectifier tubes did not exist at that time...
But in fact, and ironically, the people doing the burning were called 'The Rectifiers.'

The Scientific Method is alive and well, the inquiry is open and active, the Unified Rectifier Theory is within reach.

Seriously, gibosi, thanks. Well done. Appreciate this information and all the tube information you continuously contribute to the thread.

You've a sense of humour Ros but us rectifier users are practising an art in the end times where it's dark. So we need rectifiers to light the way.

I also would like to thank gibosi for work well done. Head-fi is better off with him. He shared with me a document he wrote on 4 volt rectifiers of the different type and class. That is a fantastic contribution. Thanks again Ken.

 

[UntilThen]

Martens, designer of ALO Audio Studio Six on tube rectification: “I do realize that yes, most often the first impulse of many (most?) Electrical engineers upon seeing a tube rectifier in use is to say: ‘Hey, why don’t you just use some good fast diodes in there and a timed soft-start circuit? You can get rid of that big, hot and wasteful tube rectifier!’ Well… the virtue of a properly implemented tube rectifier also makes itself known in the resulting sound of the amp.”

 

[UntilThen]

I think my upcoming Glenn 6EL3N is better! <mic drop>
(BTW, I think that will be its final name)

Mate you have my blessing to call your amp that. This reminds me of 'Six Bladed Knives' by Dire Straits, a nice song.

 

[UntilThen]

I have two General Electric 6BL7GTA (1959) and an adapter (two to one) that I'd like to give away or at least get any offers for, I've just had a fiasco of problems getting the right adapter for my Darkvoice amp (from China, from Bulgaria...nothing works ) and am throwing in the towel on this project/experiment, please take this thing away from me! I'm sure the adapter was wired for a parallel wired amp as it does not work well on mine (In series wired) PM me

My first tube amp is a Darkvoice 336se. One day while talking in the Darkvoice 336se tube rolling thread, someone pop in suddenly and said, 'Darkvoice 336se is the bane of my life. It's the start of my tube amps addiction that ultimately led me to the EC 445'.

For best result in the DV 336se, use a Tung Sol 5998 in the power slot but that will cost almost as much as the amp.

 

[2359glenn]

Glenn, was doing some digging on this. I think they are made by Philips in Eindhoven, Holland. Here is one that looks identical, it is an E424, which was a Philips tube, a REN904 equivalent. Same code on the bottom 2 FL. I don't think they are Telefunkens, looks like that seller had some bad info...

Still gorgeous tubes though.

https://www.ebay.com/itm/Philips-E4...Audio-Tube-Valve-Rohre-Amplifier/253958550653

Thanks for the info.
I got screwed as usual when I buy expensive tubes.
This guy is selling fakes by putting them in reproduced Telefunken boxes.
I am sure they are good tubes but not what I thought I was buying.

One thing interesting about this tube is they have a built in capacitor between the plate and cathode.
Probably to stop oscillations, It is made of two plates lined up with each other one attached to the plate and one attached to the cathode interesting.

 

[whirlwind]

Deyan's adapters have arrived. Thank you sir for the fast service.

The adapters will stay on the tubes now.



My Osram KT53 have two different constructions...I will be on the lookout for another that looks like this.



Glenn, if you are not happy with the tubes maybe you can get a refund

 

[L0rdGwyn]

Thanks for the info.
I got screwed as usual when I buy expensive tubes.
This guy is selling fakes by putting them in reproduced Telefunken boxes.
I am sure they are good tubes but not what I thought I was buying.

One thing interesting about this tube is they have a built in capacitor between the plate and cathode.
Probably to stop oscillations, It is made of two plates lined up with each other one attached to the plate and one attached to the cathode interesting.

Will you keep them, Glenn? Could maybe ask for a partial refund since they were not as advertised.

 

[Xcalibur255]

Thanks for the info.
I got screwed as usual when I buy expensive tubes.
This guy is selling fakes by putting them in reproduced Telefunken boxes.
I am sure they are good tubes but not what I thought I was buying.

One thing interesting about this tube is they have a built in capacitor between the plate and cathode.
Probably to stop oscillations, It is made of two plates lined up with each other one attached to the plate and one attached to the cathode interesting.

Wouldn't a capacitor that old be problematic?