The Cayin HA300 amp is so powerful that my volume control is between 7 - 8 o'clock at normal listening levels when using my HD800 headphones. The 170HA is apparently even more powerful. Jeff.

I found his e-bay listing. I noted that he also has Mullard CV6 tubes for sale at the same price of 100 BP per quad-set. However, his plate current measurements of 19ma seem to be impossible as the best measurements that I have ever seen are ~9 - 10ma. Jeff.

What is the expected lifespan of the Acme 300B tube and what is the warranty time period? Jeff.

Tubes were in very good condition and very well packaged for travel.

That type A version looks like the spare version with the perforated holes that are larger. My stock SR3 earpads appear to have much smaller perforated holes. Jeff.

Where do I purchase replacement stock earpads for my iBasso SR3 headphone?

What is the purpose of that fuse? Does it protect the amp from damage if the output tubes short? I am asking that question because the Cayin HA300Mk2 amp also has another single fuse near the power cord input, which I presume is there to protect the power supply. However, each 300B tube also has...

My Cayin Ha300Mk2 amp has fuses that will protect the amp from damage if there is a short (or other catastrophic failure) of the output 300B tubes. Why does the Aegis amp not have fuses to protect the amp from damage if the output tubes short? Jeff.

Could you please expand on what you mean by using the term "lifelike" by describing more precisely the specific changes in tonality/timbre that you are experiencing with the Aegis amp that you could not accomplish with the Cayin HA300MK2 amp? Also, now that you are acquiring a greater variety of...

Do you have experience comparing the tonality of the ZMF Aegis amp versus the Cayin HA300Mk2 amp? I realize that the question is complicated by the fact that each amp's tonality will be greatly affected by the choices made when tube rolling. However, can one come to a reasonably valid...

They do not have Sylvania 22de4 tubes, only GE and Philips. Jeff.

I would like to purchase the Sylvania brand of 22de4 tubes (minimum of 4) for my Cayin HA300Mk2 amp - do you know of a seller who I could contact? Jeff.

What kind of adapter would I need to use to run my Susvara (XLR cable) from the speaker terminals? Could you please provide details? Why would it sound better? I presently never use my Susvara with the Cayin HA300BMK2 because it sounds thin and bright and not full-bodied. I only use my Meze...

I have noted that Wes has a pre-production model where the paintwork on the transformers have a lot of turquoise (bluish-green) color mixed with brown and black. Do the post-production models that will become available for sale soon also have this turquoise color? Another question. I am...

Do the 6S5S tubes require a different adapter than the Pinnacle tubes? Jeff.

I have a related question. What effect does deliberate tube mismatching have on the sound quality? For example, let's presume that one takes a single brand of single-triode driver tube (eg. Mullard CV6) and that one one tube example has a transconductance measurement of 3200 microHos with a...

I have found another source for Pinnacle 6J5GT tubes. https://www.laboratoriomusicale.net/en/6j5gt-pinnacle-nos-triode-tube-selection Note that they are cheaper than Langrex and they offer printed measurements of matching measurements. Jeff.

I have a question regarding the Pinnacle 6J5GT driver tubes that I purchased from Langrex. I was reading the following piece by Thomas Mayer - http://vinylsavor.blogspot.com/2013/03/tube-of-month-6j5.html He stated that if two of those tubes are used in parallel that it can result in too much...

I did extra pay to have them matched. If there are no measurements provided on the box or tube, how do I know that they were matched? Jeff.

I received 4x 6J5GT Pinnacle tubes from Langrex. I requested that the four tubes be matched because I wanted to use them as a matched quad-set in my Cayin HA300MK2 amp. The 4x tubes I received do not have details or any measurements so I have no evidence that they were matched. If you purchased...

Can these 274b rectifiers be used in a Cayin HA300 amp? Jeff.

You have great influence on me as I have followed your lead in purchasing GEC/Mullard CV6 tubes and Russian 6C8C tubes. So, I have therefore decided to purchase a quad set of these recommended 6J5GT tubes that are being sold by Langtrex. Jeff.

How do they sound from a musical timbre/tone perspective? Are they warm or clinical/thin/analytical sounding? Jeff.

I would definitely not recommend any Sophia Electric 300B tube as two of mine failed within <3 months of use. Jeff.

WE and Takatsuki and Elrog are mentioned as 300B tube choices. I know of one very important consideration - the WE 300B tubes have a 5-year warranty, which is priceless considering the cost of replacing a prematurely failed 300B tube. Jeff.