36 watter, lets get this party started !!

stevesuk · Post by **stevesuk** » Sat 01/31/04 7:59 am

I have attached a 5 minute sketch of a possible chassis layout to get the debate started

I propose a 20" X 6" ? head type chassis layout roughly like a JTM45 or 4 EL34 plexi (which seems to work) 4" shorter. usual 2 1/2" ish' height.

Most gurus reckon 2 1/4" space between valve centres. Place any can caps to the top or inside. A plexi 100w can fit everything in a 7" deep chassis so it should be possible. I will try different dimensions and bend up a chassis on Monday to try it out. As you can see from the attached drawing, graphic design is not my strong point, so I will hand draw it and cut out the holes etc. first.

Come on chaps, get involved

Steve UK

stevesuk · Post by **stevesuk** » Sat 01/31/04 8:50 am

I know it is bad form to reply to your own posts. This is an afterthought !!

I have removed and measured my JTM45 with KT66s that I remember now didn't fit when I had finished !! not enough space, so i had to move the OT.

Anyway it has 8 components all in a line all about 2 1/4" apart. It is 20" X 6 1/2" and i have attached a pic. If you can imagine the valves taking up the positions of the various cans, KT66s etc. It should take 7 or 8 valves easy !!
e.g. in order 1 X GZ34, 4 X EL84s, 3 ? X 12AX7s.

Steve UK

Professor · Post by **Professor** » Sat 01/31/04 11:52 am

i think it will all fit in the 18watt chassis especially if you were to use standup transformers.

i do like the idea of the tubes being on top of the chassis like a head layout. this could save production costs also by just offering one chassis for both head and combo.

stevesuk · Post by **stevesuk** » Sun 02/01/04 5:44 am

Vox UK (and agents in USA ?) can supply AC30 trannies with a big but!! It seems the OT and choke are worth investigating but SS "rectumfryer" Yuk !!

Q. Are transformers still available for older AC30 amplifiers?

A. We currently have a small stock of the Mains and Output transformers as well as the HT Choke for the AC30 Vintage & Limited Edition models made in the early 1990's by Rose Morris. These will work in all early AC30's but fitting may require mechanical modification to the chassis and valve rectifiers have to be replaced by a solid state diode bridge.

We also have transformers for the current range of amplifiers that can also be used in some older amplifiers.

Post by **Plexi** » Sun 02/01/04 11:25 am

A heads up on the trannys... There is not way i'd use the ones in the re-issiue..even though they do have a tube recto.. They are crap.. i have another on here right now..and it has a Bad PT.. thes are built pretty much like all the rest of the line..like marshall 900, JTM30,JTM60, and Vox AC15.. i'm pretty sure they are Drake.. I have changed too many in amps.. From just blown, to the most awfull hum mechanical vibrations i have seen in trannys...So i would find something else besides these..
Stay clear of them

Richie

Post by **Plexi** » Sun 02/01/04 11:28 am

Oh..

""Q. Are transformers still available for older AC30 amplifiers?""

Yes those are out there.. heyboer,and a few others build them ..HUGE beasts..lol I have one of the more original types from them..And they can make them with more modern leads..or can make them look exactly like the old ones.. I think those cost a little more..

Richie

stevesuk · Post by **stevesuk** » Sun 02/01/04 1:43 pm

Richie,
Thanks for the advice. I have had a look around, and the attached PT from VVTransformers seems interesting. Cheap too, as it includes tax and postage.

Here is the spec sheet.

http://www.vvttransformers.co.uk/vth107340.htm

I presume the reason the AC30 PT has a 6.3V @ 6 Ampere rating is the 3 extra 12AX7 valves for the reverb/tremelo. Is there really 11 valves in an all valve AC30 ? No wonder there isn't an ac30watt.com sister site. !!!

I am assuming 300V CT @ 180mA, 6.3V @ 4A and 5V @ 2A will be adequate.

Unfortunately they don't do a 4K OT, so on with the search.

Steve UK

Samycasanova · Post by **Samycasanova** » Mon 02/02/04 8:27 pm

Is this a clone of some sort of amp or is a new one ?

Post by **Plexi** » Mon 02/02/04 9:21 pm

Its the 18 watt circut.. but it will be useing 4-EL84s..so it will have twice the power/volume.. An 18 on steroids!!! Thats about it.. Just the power section will be kinda different, bigger trannys..

Richie

GlennG · Post by **GlennG** » Mon 02/02/04 11:28 pm

I`m sorta late to this party but I like what SteveUK is saying about the chassis. I have a Mojo Marshall small head box and 7 inches is the max depth demension including faceplates. The chassis depth without faceplates is 6.75 inches. With the rear panel in place, 7 inches is the inside front to back demension. In this cab a chassis could be 23" long and still fit inside. Might be nice to have extra room for cap-cans and what not. Sorry to ramble but I`m in the process of cutting down one of Graydons old (18 Watt) head chassis` to make it fit in a regular Marshall small head box. Its nice when chassis` will fit "off the shelf" cabinets. If this has already been brought up forgive my redundancy.

Glenn Gertis

GlennG · Post by **GlennG** » Mon 02/02/04 11:31 pm

This chassis is a bit to big for a standard "off the rack" Marshall small head box. 6.75" + faceplates would be just right

Glenn Gertis

stevesuk · Post by **stevesuk** » Tue 02/03/04 4:01 am

I am going to build a head chassis to fit a head or a combo cabinet. Ideal if your requirements change and you want to use a 4 X 12" for example. Put the amp chassis in a head box. Standalone put the amp chassis in a combo. Or just build two !!Â¬

Steve Uk

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36 watter, lets get this party started !!

36 watter, lets get this party started !!

Just curious !