umph

[quote name='Passinwind' timestamp='1423776974' post='2689026']
I just did a bit of benchmark testing in RMAA and saw a few subtle things that may need massaging, but it looks pretty good all in all. These figures are with both the high pass and the parametric EQ engaged, neither of which change the measurements all that much when bypassed.


[/quote]

what software do you use for making tests like these andd doing sweeps?

[quote name='Beer of the Bass' timestamp='1426517643' post='2718717']
That 400 watter must sound quite impressive! I notice you've only got bass and treble controls - is it a Baxandall/James tone stack or something else? I'd be curious to know who you're using for your custom transformers too.
[/quote]

yeah I stuck with a bax style stack, got it so it's actually flat the nightmare is finding the pots with the correct taper. I use John wood in nottingham for transformers, he really knows his stuff.

I like the 400watter because you can drown out the drums with it at about half volume which leaves some nice headroom!

Thought I should put up some pictures on here of the prototype builds I'm doing!

First up is a 5watt UL 6v6 based amp with a 6sn7 preamp and valve rectified HT.

Gonna be very unique sounding when its done and great for home recording. The transformer is special wound and good for well below 20Hz at full power.




Next is the 6Xel84 amp which is kind've like a hot rodded ac30, The valves are going to be a little underrun voltage wise for reliability so I'm expecting around 40watts from it in fixed bias and 20 in cathode bias mode (which is switchable).

It's also going to have channel switching built in with two seperate preamps.

I need to get some more up to date pictures of this project done.




And lastly is the 400Watt beast with 8KT88, I've had this doing 420W at 15Hz on the bench which is nothing to be sniffed at!




Photography isn't my strong point haha.

Thanks for the recommendation tom, got a new website to - [url="http://www.aitkenaudio.co.uk"]www.aitkenaudio.co.uk [/url]

I think part of the mojo of the muff is the big box! You can fit the circuit in a way smaller box than they have anyways

take it to john wood. http://jwoodaudio.com/

[quote name='vocrockguitars' timestamp='1382533866' post='2253285']
New pre amp tubes just released by rocket tubes. They come in 2 Variants. A low gain version labelled as CLEAN and a Higher Grade Version Labelled as NITROUS. We have put these in several amps and they sound very nice. Cryo Treated and other mod cons make these tubes an exciting new addition to the tube tone world. A great new Vacuum Tube. You can read info about them on
[url="http://www.rocket-tubes.com"]www.rocket-tubes.com[/url]

We are proud to be one of the first to get hold of these in the UK [attachment=146759:rocket-tubes-12ax7clean.jpg][attachment=146760:rocket-tubes-12ax7nitrous.jpg]
[/quote]

The website doesn't say a lot, there are no prices and i'd like to know what factory they came out of? I'm not a huge fan of the chinese cheapo 83's. Can't see the jacket doing a lot for microphonics.

quite a few other websites offer matching services like this.

[quote name='Billy Apple' timestamp='1381398688' post='2238406']
How do you know that?
[/quote]

had them on zee benchh, it's the same as the orange 200watter. They don't have the proper drive or OT's

[quote name='Billy Apple' timestamp='1381263996' post='2236784']
The amp spent the today in the factory. Matamp could not really pin point the crack I could hear, and they thought the humming noise from the transformer nothing to be concerned about. They replaced the power switch and re-soldered a few bits and pieces they thought looked dry. It was only pushing 160 watts and seeing as the power valves are knocking on 3 years there was talk of replacing them. But, each power valve was tested individually and found to be OK. The drop in power was traced to a duff pre-amp valve which was replaced. The power is back up and I've been saved a new quartet of KT88's for the time being.

Anyway, I'm collecting from my mates on Thursday, and hopefully that's it for the time being.
[/quote]

they only do about 156watts anyway

Take it to the factory, sounds likesomething is leaking dc somewhere!

[quote name='JapanAxe' timestamp='1381146226' post='2234874']
Why not just buy a cheap used Ashdown head and use the whole power amp section and transformer?
[/quote]

because the power transformers are pants and ticking timb bombs

should be fine, just keep the voltage down if its a ss one

is it balanced?

[quote name='The Bass Doc' timestamp='1367142854' post='2061562']
OK it's ugly and heavy but sounds superb. My Wallace AC5075XT:-

[attachment=133653:IMGP0003.JPG][attachment=133654:IMGP0002.JPG]

Built around 1969. 2 x KT88s.

In the early 70s when I was young and fit I used to gig a stereo wired bass into two AC100XTs (a lot bigger and heavier!) plus two Burman 4x12s.
[/quote]

do you have more pictures of the wallace? I've heard great things about them!

All these "boutique" amps are making me feel very happy about my wiring haha

[quote name='tayste_2000' timestamp='1378722063' post='2203561']
The 400w prototype pumps out 540w clean before you introduce any distortion to it so if you're buying it you need to have some serious cabs to take what is going to come out of that amp.
[/quote]

with a little help from someone it did

Hiya, I do have a svt-300 for sale which you're welcome to buy! shoot us a message

hmm it sets any valve to 35ma, thats just not enough for some valves in some conditions. It's a good idea poorly executed

om, morcobot, big business, dfa1979 are all ace

thats the matamp pcb in there, looks like its had some bodge work done though! those 6550s definatly shouldn't be in there

[quote name='Dave_the_bass' timestamp='1374002272' post='2144170']
Just to clarify, my follow up question was:

When using my octave pedal on one of the channel effects loops, in mix mode (Shuttlemax amp), why do I get a delay/echo effect?
[/quote]

thats a strange one

[quote name='flyfisher' timestamp='1373199293' post='2134559']
Are we talking RMS watts or peak watts or valve watts or different manufacturer's watts or . . . . (continued forever)?
[/quote]

watts a watts a watt

[quote name='Bobo_Grimmer' timestamp='1372348383' post='2124696']
Super. i'll look into it. May invest in something a little more rugged.
[/quote]

I recommend the gold lion or winged C varients, they seem to have the best life out of the valves I've used.

yeah, the marshall design doesn't lend itself to headroom either

if you struggled with the sound city for volume you're gonna struggle with the behringer

get it fully serviced and recapped and i'll bet it shuts up!