18Watt.com

Just got a GDS 18watt kit completed and find the highs a bit fizzy with a G12M 25.
I've read a lot of poeple like the G12H 30 in there... but do I get the 55hz or the 75hz version ?
thnks for any suggestions !

The greenback is the most popular ceramic speaker for this circuit. If your highs are "fizzy" it could be an indication of an issue with your circuit. Posting a recording of it might help. Sometimes fizziness in the distortion means you may need to apply the Paul Ruby Mod.

Thanks,
Josh

I just did a search for that mod and found nothing I could understand...
Is there a schematic for this somewhere ?

Thanks,
Claude

Take a look at reference number 9: files/JMPGuitars_18_Watt_Superlite_TMB_Schematic.pdf

About the speakers.. i have a bunch of different celestions. Here's my opinion in a decending order:

1. Old 70's G12H30 75Hz: it don't get more beautiful than that one... by far
2. Chinese greenback G12M 25W: top sound!
3. Heritage G12h30 55Hz UK made: top sound, but the G12M is nicer.. less boomy
4. G12M65 UK made: a little under the G12M30 ..but still very ok
5. Vintage 30 UK and China: nice raspy sound.. I tend to like it.
6. Alnico cream 90W: wayyyyy overrated speaker. Not worth it at all. It never sits 15 minutes in an amp of mine.. generic highs and lows. Naaah.. don't like it at all

JMPGuitars wrote: ↑

Tue 08/02/22 8:04 am

Take a look at reference number 9: files/JMPGuitars_18_Watt_Superlite_TMB_Schematic.pdf

THank you !
Looking at that brings up a question I have, not sure this the right forum for it but: What is, in general, the motivation for ditching the Tremolo and going TMB, and how different in character would that channel be compared to the normal channel ?

Hebaton wrote: ↑

Tue 08/02/22 11:42 am

THank you !
Looking at that brings up a question I have, not sure this the right forum for it but: What is, in general, the motivation for ditching the Tremolo and going TMB, and how different in character would that channel be compared to the normal channel ?

You're welcome. The simple answer is whether or not you like tremolo. Some people love it, some people don't care about it. The real character and tone is primarily from the power amp section of the amp, but some people like having the extra tone shaping tools in the preamp section.

I much prefer the 20W 75Hz Heritage Greenback to the Heritage G12H30 55Hz. The G12H30 has a big low end, but I just don't care for the top end. The 20W Greenback is wonderfully warm, woody, with a detailed and chimey top end that is never strident or too forward. The low/mid crunch is great and breakup is smooth. It's a great match for the amp. They are both great speakers, so I'd say the choice ultimately rests with what you ear prefers, as well as the sound you are going for with your music. The G12H30 is a more sensitive speaker and as such, slightly louder with later breakup. If I had to pick one speaker to work with the 1x12 18W combo cabinet, it'd be the 20W Greenback. If it were a 2x12, it'd be two 20W Greenbacks. I play Custom Shop Les Pauls with unpotted, underwound PAF pickups. During the early 18W days, a lot of guys were mixing a G12H30 Anniversary with an Alnico Blue or a Greenback and a Blue. Hard to go wrong with any of them really.