scott wrote:the funniest thing about the Traynor YVM-1 (50W tube PA) is that it's got a master volume knob that is totally useless in a guitar amp context... it's a volume knob that affects all the channel's volumes, but there are no gain stages, no *nothing* between the channel volumes and the master volume. so if you're using a single channel for guitar, it's the equivalent of having two volume knobs instead of one... not a preamp volume and master volume, but just two volume knobs one after the other. too funny.

there's a Laney tube PA on eBay right now that I would love to use as a platform for modding. it's in the US even. already too many projects and not enough time though.

Although a lot of PA amps have differant preamp sections, there are also others that utilise the same preamp that the manufacturer's guitar amps use. The old Marshall PA amps come to mind, as they followed this configuration, with the exception that they had two more inputs/volume controls than their guitar/ bass heads.

As far as switching the output tubes over to 6L6's, I generally agree that this is a fairly simple procedure, though some British amps , like a lot of Selmers and Sound City's used cathode biasing, so you will most likely have to change a few capacitors in the biasing stage should you want to use 6L6's. --This is still a very minor thing, though.

This being said, I have have a mixed opinion of what Scott said about amplifier wattage. A 30 to 50 watt guitar amp is fine for bands that have fairly moderate stage volumes, with the 30 watt amp being the better of the two, as you can get some serious power tube saturation at relatively decent volumes. I agree with this 100%.

OTOH, a 30 watt amp isn't going to cut through an SVT and a really loud drummer, especially if the bassist compensates his volume to match the loud drummer. Then you'll need a 50 or 100 watt guitar amp to keep up. Sadly a situation that I've seen a lot of times, is that bands will throw restraint to the wind, and invariably a couple of band members will get into a rat race to see who will be the loudest, with the person with the lowest wattage amp getting buried.

With a 100 watt amp, you do have the option of pulling the outer pair of power tubes, and resetting the speaker output selector to the next lowest ohmage rating to get a 50 watt amp. This is a fairly commont thing a lot of guitar players resort to in order to reduce their stage volume, and I've done it myself.

When you pull the outer pair of tubes, you are changing the internal resistance of the amp, and must compensate this by reducing the ohmage at the output transformer to balance the resistance change caused by removing two of the power tubes. Orange Amplification used a variant of this scheme with their OR-80 amps. The transformers were the same exact transformers as their OR-120's, they just didn't wire the two extra tubes into the circuit, and the ohmage compensation was internally hard wired at the OPT.

Quick update but most importantly a thanks to all the chaps who've contributed - I've learned SO much and now have a solid base-line of amps I'm looking for.

I found a 69/70 Selmer T'nB 50 In a loacl shop and the guy asked 325 (british) for it - I went back later to check if it was the reverb version (nice for home practice and recording) and he said "385 - sorry mistake".....anyway that kind of took him out of the running price wise. Theres something on ebay near where I live that will be Sweeeeet if I win.

Love the fact that with the Selmer you can run a lead between the Bass and treble and use the volume knobs to mix the two....man that is cool.

Anyway with gain I'll likely be using a Harmonic Percolator replica so the issues revolving around cranking it to natural distortion may not be a major issue.

I figure I'll have an amp head within two weeks so need to look into the cab next....again if anyone has any UK-centric tips for a fantastic sound I'd like to hear your opinions.

One thing with cabs and speakers - From my hifi anal days I'm sceptical that vintage cones will not have deteriorated. in the same way that vintage guitar electronics don't actually mean practically better is there any advantage at all in using 30-40 year old speakers that have been well used??

Dave ManReads wrote:I found a 69/70 Selmer T'nB 50 In a loacl shop and the guy asked 325 (british) for it - I went back later to check if it was the reverb version (nice for home practice and recording) and he said "385 - sorry mistake".....anyway that kind of took him out of the running price wise. Theres something on ebay near where I live that will be Sweeeeet if I win.

Love the fact that with the Selmer you can run a lead between the Bass and treble and use the volume knobs to mix the two....man that is cool.

1. You played it, right?

2. Linking bright and normal Channels was also used with old Fender tweed amps as well as the old Marshalls. --I don't know how it works with the Selmer amps, but with the old Fenders and Marshalls, you plugged into the Normal (Bass on the Selmer?) channel and linked to the bright channel, and used the volume for the bright channel as an extra volume control.

Furthermore, guitar speakers are less susceptible to deteriorating cones due to the fact that the surround is either a doped (The shiny black stuff around the edge of the cone) pleated continuation of the paper cone, or doped fabric like a PA speaker. As you know, HiFi Speakers use a foam edge surround that is a lot more susceptible to dry rotting and UV induced deterioration. There are many guitar speakers that are between 40 and 50 years old that still work fine, and sell for a LOT of cash. --The old Pulsonic cone Celestions from the 60's like the G12M-25's (that apparently Selmer used along with Goodmans and Fanes) and the Alnico Celestions as used by Vox sell for close to $500 a piece with the original cones.