Here are Things learned about Valve 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 of your amp 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. […]
We have broadened our range of EL34‘s in our store. But which one is best for my amp? This is a handy quick guide to EL34’s We now have :- JJ EL34 JJ EL4 II JJ EL34L EH EL34 Tung Sol EL34B We offer all the above in matched pairs and quads. The EL34 was one of the last additions to the audio valve market and it was introduced by Mullard in the early 1950’s.
Which EL34 ? We explain differences on selected types Read More »
A Marshall JCM900 amp arrived. The JCM900 combo is basically a 100 watt twin 12 inch speaker combo and is a true Marshall stack in a matchbox. Nice and easy to transport. When new these amps supplied in two variants, with one having 4x EL34’s in the output and the other variant having slightly lower power with 4x 5881’s. This amp was dead. Zero output and a lovely hum. Inside the amp proudly displayed
I have now worked on two Marshall JCM2000 amps and both are around 10 years old. Both had very similar faults. The fault on both was that the amps sounded “rubbish” and both were cooking the EL34 output valves. Instead of running at about 45 mA of bias current the lowest adjustment you could achieve was over 100mA. recipe for output valve shortened lives and destruction. The fault is clearly in the bias circuit. I
Rectifier Valve ? Many of the vintage amplifiers such as the Vox AC30 , Fender Twin Reverb use a rectifier valve. Other amps use modern silicon diodes. The rectifier valve ( or diode) is a key part of your amplifier’s power supply. Its job is to “convert” or rectify the AC voltage coming from the transformer into the high DC voltage needed by your valves in your amplifier. The output valves need the highest voltage
This weekend, I worked on a lovely 6 year old, Marshall DSL50 amp head. This was the unit I mentioned in a previous post that was awaiting my attention. It was working however the output valves were mighty hot. I checked the bias on those two beautiful EL34’s and found I could not adjust the bias below 68mA. They were running at 90mA when I first tested the amp. (Update Feb 2018 : we now
New valve testers now installed. Click here and see how we are ensuring you get the best quality valves.
Genalex KT88, EH 6973 & Tung Sol 9591A in stock
We normally ship orders same day for orders received Monday -Friday before 1.45pm and before 10.30am on Saturday.