Marshall 18 Watt Forum?

[boots]

I don't see too much discussion about Marshall 18 watt amps. There is a website didicated to them, but it seem to be defunct or under construction or something.

I'm surprised there is not a forum dedicated to them. I am thinking my next build might be an 18 watt clone, and was hoping to do some research first.

Does anybody know if there are any good threads on this site about 18 watters?

[M Fowler]

We can always discuss 18w Marshalls on this forum no problem plenty of us members from 18watt.com are members here.

We could move to the tech section to discuss.

Mark

[xtian]

I documented a recent 18-watt Lite IIb build.

https://tubeamparchive.com/viewtopic.php?t=17964

[M Fowler]

I was just over to 18watt.com and the forum is working fine to me?

It takes a little effort logging in to guess at the weird words you have to try figure out but after a few try's I get it.

Mark

[Colossal]

Hey Boots, I just checked and 18watt.com is working fine for me; perhaps it was just offline when you were there. Over the years, they've had a lot of technical difficulties with their database getting corrupted from hacking and often they would have to roll back the index to a past date, losing weeks worth of current posts. Links in "restored" threads would often point to non-existent or wrong files so they really got hosed. They seem to have gotten past that in the last year or so. I posted quite a few drawings of mods and other things in the 18watt.com community in years past but I think a lot of them got lost with the damage the BBS suffered; maybe some of it is still floating around, I dunno.

That said, there are plenty of guys here that have a lot of knowledge about and experience with the Marshall 1974 and its variants. There have been many documented 18W 2xEL84 and 2x6V6 builds here; everything from a detailed analysis of the Xits X10, Dr. Z inspired 18W variants, 18W Plexis, 18W Trainwreck inspired Liverpool and Rocket variants, etc.

I personally really love the EL84 sound. Search for threads and posts by MFowler, Xtian, Dartanion, ToneMerc, Lonely Raven, The Hall bros., Surfsup, RJguitars to name just a few and you'll find a wealth of information.

[rock_mumbles]

The 18 Watt forum software got broken a year and a half ago or so ...
so new users can't be added, and things like the gallery don't work ...

[Colossal]

The 18 Watt forum software got broken a year and a half ago or so ...
so new users can't be added, and things like the gallery don't work ...

...which is a shame. A lot of good information and discussion got lost.

[katopan]

Yeah, it's still a great discussion place for those of us who regularly check in and have an existing account. But a real shame no new members can be created. It's often the new blood and questions, build logs, etc that come with them that keep a forum going. I am worried that without some sort of rebuild some time soon the 18Watt forum may end up getting lost. There were some efforts being made quite a while ago but they didn't get anywhere. I assume cost is a factor although they were having trouble finding anyone with the skills to do the work too.

[boots]

Thanks guys, I'm sure I will have questions as the project materializes.

The first thing I should probably do is order a PT from AES before the end of September, since all Hammond products are 10% off.

Looks like the original amp used about 300 VDC for B+.

So probably I need something on the order of 275-0-275 for the PT?

[Colossal]

So probably I need something on the order of 275-0-275 for the PT?

Yep, 275-290VAC range is typical.

[katopan]

B+ is typically around 340Vdc. PT is 290-0-290 used with EZ81 rectifier. If you go SS recto use a 120 ohm sag resistor and even then you might have to drop 10V with a zener or use a bit lower voltage PT.

[dartanion]

Lot's of "issues" exist regarding the 18 watt forum. No need to go into it in detail, so I see no issue discussing them here. In fact, I encourage it!

[M Fowler]

I agree we need to discuss more on the Marshall 18w amp on this site it a favorite amp of mine whether the Lite, TMB or Tremolo versions.

Mark

[Colossal]

@katopan

Did you by chance ever try this power reduction method for the 18W Lite or other variant? (see attached). There was a good thread about it but, IIRC the discussion was a little hazy as to whether the mod was really useable or it just increased the local negative feedback at the power stage.

[katopan]

Haven't tried that one Colossal. I have just removed the cathode bypass cap and didn't like the sound. As you say it just adds a heap of local feedback to the power stage. Unfortunately that gets rid of half the pentode characteristic that makes the amp sound so sweet. I've done a lot of waveform plotting with my 18W (which I posted over there many moons ago). The pentode curve and screen compression contribute such a big part to how the amp sounds.

After I built my 18W and found it was way too loud for home use, I moved straight to whole amp VVR. A while later I was then one of the three people (with Wazak and Conger) who bounced around the idea of PI/PA VVR to get the better response of PA only compared to whole amp, but being able to ditch the post-PIMV. We all tested it out and reported back the success within days of each other. Never looked back for power reduction methods.