My Peavey 6534+ got a tune up


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Dec 23, 2014
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Adelaide, Australia
Well back before we recorded our demo in June my amp started to sound bad ... decided it was time for some new tubes. So I went online and did my research and in the end decided to replace the Ruby EL34BHT power tubes with another set the same, but I had to order them from the USA and they took a while, so the preamp tubes I ordered from a seller here in Australia arrived first and I had a go at installing them.

Well I only got as far as V1 and I mashed a socket. Must have had a crooked pin on the new tube. So I had to take it to the best tech in town - FM Audio - and Frank worked it right over for me while installing the tubes I gave him. He was able to get the bias into the right range without a bias mod after upgrading the screen resistors to a more usual EL34 value. Don't ask me what the value on them is because I forgot to write it down! Anyway the 6534+ can get into the right temperature without a bias mod, so that's good to know. Other issues he fixed might be because of bad quality checks at Peavey's end. The chassis was not aligned properly and there was a danger of damaging the PCB because the knobs protruded past the protective housing. Frank aligned it properly and redrilled the steel cap and located it against the wood like it should be, and the grille fits in properly now. He also said that the lead-free solder was sloppily applied so he removed all of it and replaced it with leaded (60/40) solder.

The preamp tubes installed were as follows (in order from right to left, looking at the back of the amp):

V6: Tung Sol 12AX7 (RHYTHM)
V1: Tung Sol 12AX7 (INPUT)
V2: Tung Sol 12AX7 (LEAD #1)
V5: Ruby 12AX7 AC5 HG (LEAD #2)

With the aid of a genuine NOS Mullard tube straightener I have since switched V2 and V5 so it is as follows:

V6: Tung Sol 12AX7 (RHYTHM)
V1: Tung Sol 12AX7 (INPUT)
V2: Ruby 12AX7 AC5 HG (LEAD #1)
V5: Ruby 12AX7 AC5 HG (LEAD #2)
V3: Tung Sol 12AX7 (EFFECTS LOOP)

I just found the Tung Sol in the V2 spot made the lead channel too strident. I like the sound now, darker with more sustain and I can have the presence where it was with the old JJ there.

As stated above the power tubes are a matched quad of Ruby EL34BHT tubes. They are actually cryogenically treated ones; that wasn't necessarily a preference but they were the best price I could get and they are sounding really good so I lucked out.

I hope this is helpful to anyone working with this series of amps (Peavey 5150/6505 series), and especially those who have a 6534+

Our demo was recorded with it in the first configuration. I did have to wind the presence back a fair bit to get my sound with that tube combination.

EDIT: With regard to the chassis alignment problem, here are a couple of photos that show what was wrong and how it was fixed.

The day I bought the amp:


The day I got it back from Frank:

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