Here are Things learned about Tube Amps in 2018 .
They are in no particular order. Perhaps some useful info about your amp.
I thought I would share them before they faded out of my head
Loudness
Your ears respond to sound like a compressor. So when you ears hear the sound from a 10 watt amp and a 100 watt amp, you don’t hear an amp that is ten times louder. Your ears hear sound that is two times louder. So you might be disappointed to that your new 100 watt Marshall is not twice as loud as your previous 50 watt Marshall.
This is a different issue to speaker efficiency. Some speakers are more efficient than others in converting the electric signals to sound. The classic example is the standard Celestions versus the Alnico blues in Vox AC15/30’s The Alnico magnets make the speaker more efficient so at the same volume setting it is actually louder. You can really hear the difference so they must be significantly more efficient because you can hear the difference.
Marshall JCM900’s
Most folks think that all Marshall amps use EL34 tubes in their output stage. It is kind of a Marshall ” trade mark” . Many of the JCM900’s do NOT use El34’s ! The use the 5881 which is a variant of the 6L6 tube. It is still a 25 watt valve. A number of the companies selling valve kits wrongly offer the EL34 for all JCM900 variants. You can check this by removing the back of the amp and there is usually a gold coloured sticker inside the amp or on the chassis saying use 5881’s. Make sure you check for this sticker.
Weak Vibrato in Siverface and Blackface Fenders
This is something I have known for a few years by I thought it was worth mentioning. You might notice that the vibrato in your original Blackface or Silverface amp is a bit weak. If the valves are in good nick then it is almost certainly the opt-coupler that is wearing out. The onto-coupler takes the signal from the oscillator and modulates the audio. It is made with a little neon light that is strapped next to a light dependent resistor. The two components ae wrapped in heat shrink to exclude external light The neon light gets weak over time and for these reasons the depth of the modulation diminishes. You can buy replacements. It is worth replacing this unit in vintage amps andthis brings the vibrato back to life.
Fender Hot Rod Deluxes and DeVilles go whisper quiet
If you find your Hot Rod or Deville amp goes really quiet then it is worth checking the resistors on the cathode for anode of the phase splitter. You can tell this if you turn the amp to full volume and you can just about hear the guitar when you hit a chord. Your ear needs to be next to the speaker. The resistors will not look burned. You will need to check them with a multi-meter. I believe they blow open circuit not because their wattage is too small . Thy are small resistors and what seems to get them is that the volts are too high for these little guys. When replacing them use higher rated resistors.
Tube Prices
Valves are old technology and their is lot of manual work done to make them. This makes them more sensitive to labour costs as compared to modern products which are made in highly automated factories.
The Russian valves had a big increase in factory prices in May 2018 but that was the first price increase in many years. Since 2022, there is now 35% sanctions import duty on all Russian tubes. This really jacks up the price.
JJ electronic tend to increase their prices every year and usually in the back half of the year.
All tubes are imported and the exchange rate therefore has an impact on pricing. JJ Electronic are bought in Euros and Russian valves are bought in US $.
At the end of March 2018 the £ was worth $1.40 and $1.26 in mid December 2018. Furthermore the £ was worth €1.13 in March and €1.12 in mid December. You can see that the £ has been very stable versus the Euro but a bit of a disaster against the US $.
We have to pay import duty on Russian valves but as JJ Electronic is in Slovakia there is no duty and no customs clearance charges. This might all change after March 2019.
The combination of price increases and exchange rates has meant inevitable increases. Let us all hope the £ gets stronger in 2019 and we are able to reduce valve prices !
Now that we have mentioned 2019, I wish all the very best to you and your families and friends for 2019 ( this was written December 19, 2018 so if you are reading this in late 2019 or later, I hope all your hopes and dreams came true)
Who are valvetubeguitaramps.com?
We are a family owned company based in Scarborough, UK. Headed up by Stewart Gebbie, the website burst onto the market in 2015. Stewart is a graduate electronics engineer having spent decades in the semiconductor industry working across Europe. He spent time working in the USA and a good number of years in the digital audio semiconductor business. His passion is valves and has been repairing valve amps for close on 50 years !! ( he did start very young !)
Valvetubeguitaramps is an officially appointed dealer for vales coming out of Slovakia and the world’d largest factory in Russia. All products are directly imported into the UK. No middle men. From the factory to us to you.
Using a suite of valve testers, all valves are tested once they arrive and in the past year we have shipped to South Korea, Indonesia, Cambodia, Australia, New Zealand, USA , Canada and most of the European countries.
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