67 vs 69/70 Marshall, do they sound that different?

[Littlewyan]

I've been toying with the idea of building a 69/70 50W Lead Marshall and I'm now wondering, will it actually sound that different to my JTM50?

I've gone through a lot of clips and they seem to sound surprisingly similar.

[Littlewyan]

Apparently, no one knows 0.o

[bill bokey]

I think they would be quite different both in tone and feel.

The JTM50 has a bass preamp, less gain and a softer touch. It's often hard to hear and feel those differences on video

[Tazin]

The 69/70 is brighter and more aggresive sounding compared to the '67 JTM50.

[Littlewyan]

Thanks guys

Next question, is it better to build my own or save up for a 72/73 50w Head...............

The 72/73 will cost more obviously, but it could go up in value. However if I continued to play it would the increased wear and tear counteract it going up in value? Parts may fail over time and would have to be replaced.

[Tazin]

I guess it all depends on whether you think you need to own a genuine Marshall or whether you can live with the Marshall sound coming from a clone amp. I will add that a 72/73 50w will sound slightly different from a 69/70.

[neikeel]

As stated above in general the JTM50 (f you built it to original spec.) is broadly speaking less aggressive (and also less harsh) than an early (69/70) or later 72 on metal panel amp.

Although to be honest my JTM50 has plenty of gain on tap when set correctly using my 4x12s and an attenuator, although just to be contrary I have just finished restoring a 64 JTM45 with RS trannies that has amazing amount of gain on tap (just tying to figure out why!!) the simpler circuits do depend upon good quality components including resistors, caps and transformers.

I think that the best all round 50w is the late 68/early 69 lead spec amp. I built one with Marstran trannies, added SDMs 2 in 1 mod and it is a keeper with my originals.

I have a spare new 50w chassis from Valvestorm and an original '71 board and other bits if you want a head start? (and I am in the UK).

[Littlewyan]

I think I'd feel better about using an amp that I built, simply because I'd be worried about something going wrong with an original Marshall. If a part fails in my new amp then its not so bad.

Its funny you should mention a JTM45 having lots of gain, because Johan Segeborn did some videos of JTM45s not too long ago and one of them had a lot of gain! Sounded lovely.

I was going to use Classic Tone Transformers again for this one. I wanted the HT to be around 420V. I originally wanted 380V but I think it'll be a bit squishy for my taste and I think I'm right in saying that 420V is more era correct for a 69/70.

I couldn't buy the original 71 board off you, save that for a restoration. My amp isn't going to use era correct parts so it will be wasted on me. I was going to use Modulus Amp's JTM45 Chassis and Michael was going to make up some metal faceplates for me. How much would you sell the chassis for? Where do you get your metal faceplates from? Michael sent me a sample of his and its really nice.

[Roe]

...I have just finished restoring a 64 JTM45 with RS trannies that has amazing amount of gain on tap (just tying to figure out why!!) the simpler circuits do depend upon good quality components including resistors, caps and transformers.
...

Some of the early amps allegedly had PTs that sagged more. They were rated for less current than the 1202-55

[neikeel]

...I have just finished restoring a 64 JTM45 with RS trannies that has amazing amount of gain on tap (just tying to figure out why!!) the simpler circuits do depend upon good quality components including resistors, caps and transformers.
...

Some of the early amps allegedly had PTs that sagged more. They were rated for less current than the 1202-55

Mine is and RS PT running around 450v on the plates. At the moment it has my testing Marshall logo'd (Sovtek thin base) 5881s. Being snobbish I was going to replace them with GECs or some EL37s but it sounds so good think I'll keep them.
Sorry to hijack thread!
The chassis is the galvanised 50w. Robert lists these at $65 (so add VAT and duty if importing to UK). Depends if you are going laydown or stand up PT (mine vs the Modulus). I can throw a set of valve sockets for £50 total?

[Littlewyan]

I was going to use a laydown transformer. Where do you get your metal faceplates from?

[Roe]

...I have just finished restoring a 64 JTM45 with RS trannies that has amazing amount of gain on tap (just tying to figure out why!!) the simpler circuits do depend upon good quality components including resistors, caps and transformers.
...

Some of the early amps allegedly had PTs that sagged more. They were rated for less current than the 1202-55

Mine is and RS PT running around 450v on the plates. At the moment it has my testing Marshall logo'd (Sovtek thin base) 5881s. Being snobbish I was going to replace them with GECs or some EL37s but it sounds so good think I'll keep them....

Does the RS seem to sag more than the -55?