The humble 12AX7 vs the lesser used 5751?

[Soliloquy]

[quote name='dood' post='1123452' date='Feb 11 2011, 12:52 AM']Yeah, i'm a big fan of the Harma Diamond STR - They are a premium selected and tested JJ made ECC803S clone as you rightly say. Brilliant tone - I may end up with another, just fancied trying something a little different. Would love to find me a nice Tesla Short Plate E83CC![/quote]


Hi Dan,

What are you using the valves in ?

Is it the Hartke ?

[Dood]

[quote name='Soliloquy' post='1124270' date='Feb 11 2011, 07:51 PM']Hi Dan,

What are you using the valves in ?

Is it the Hartke ?[/quote]


I've got a stock JJ in the Hartke and another valve pre has a GT but yeah it'll be for the LH. Should be interesting to see what difference there is between a Harma and a JJ.

[Soliloquy]

I have a JAN PHILIPS 5751 for sale if anyone is interested.

I got a Shuttle 6.0 in a trade a week or so ago, and experimented with a couple of different valves. The stock Ruby was very gritty sounding. I've now traded the Shuttle for an LM2, it's going fitted with a JJ Electronics 12AX7.

[Dood]

I nearly went for the Jan Philips, but I managed to bag myself a bit of a special 5751 - I thought I'd treat myself! Details to follow, but I think I'll keep you all waiting!

[Ancient Mariner]

[quote name='dood' post='1130949' date='Feb 17 2011, 01:08 PM']I nearly went for the Jan Philips, but I managed to bag myself a bit of a special 5751 - I thought I'd treat myself! Details to follow, but I think I'll keep you all waiting! [/quote]

Tease!

[AttitudeCastle]

[quote name='bigjohn' post='1121296' date='Feb 9 2011, 12:59 PM']All depends on yer gear doesn't it really?

And how much gain you want / need.

If you need less gain that's available from your gear and you're looking to tighten up your tone, or want to emphasise your mids, I'd swap em out and see how it goes.


I'm pretty sure (from memory and a quick a google) that JCM800s use ECC83s and they're gain monsters.

My SVT-IIP has 2 12AX7s in and hardly distorts even at extremities.

So I can't see either of these amps becoming better / more usable with a swap.[/quote]

I have no idea why the JCM800 bass amps were discontinued! They are fantastic,

I played a guitar one with some parts from the Bass version in (very chop shop) so the treble control couldn't go above 3 or it was tinny hissy city!

They can "crackle" nicely when you up the gain and dig in, and full on break up at 11!

My brother uses some valves a marshall tech reccomended him in his guitar rig, which are gainy too the max, they distort nicely even on the clean channel when pushed with a hard signal and the high gain channel is another story!

I'm interested in ECC83s, they sound good as far as a amps i've heard and thats about all i know about valves Interesting read that article though!

[Alien]

[quote name='dood' post='1121242' date='Feb 9 2011, 12:28 PM']I've not really seen much of a mention of the 5751 when it comes to bass gear to be honest - and it's gain isn't that much below a 12AX7. IIRC 12AX7 = 100, 5751 =70 and the 12AU7 is about 30? So would it be a worthy valve to roll with?[/quote]

The 12AT7 / ECC81 has a gain factor of 60, compared to the 5751's 70, which makes it the most similar in terms of gain. They come up quite often at reasonable prices, possibly because everybody seems to want the ECC83 / 12AX7 instead.

A

[nick]

[quote name='umph' post='1124259' date='Feb 11 2011, 07:44 PM']you sure they're 803's? they have a different pin out. Great valves non the less though, worth a small fortune if you have some of the originals![/quote]

According to Watford Valves they are : [url="http://www.watfordvalves.com/product_detail.asp?id=1423"]Harma STR ECC83[/url]

[Dood]

[attachment=73273:172415_1...397885_o.jpg]

Well the cheeky lil chappy has arrived. I don't think I'm gonna get time to install it or do any proper listening tests till tomorrow - but I thought a teaser would be nice for ya!

Dood

[Dood]

p.s. - who is geeky enough to try identify this one then?

[umph]

[quote name='nick' post='1133642' date='Feb 19 2011, 06:01 PM']According to Watford Valves they are : [url="http://www.watfordvalves.com/product_detail.asp?id=1423"]Harma STR ECC83[/url][/quote]

oh another remake thats nothing like the original

[Dood]

[quote name='umph' post='1142346' date='Feb 26 2011, 02:10 PM']oh another remake thats nothing like the original [/quote]

Technically it's not a remake - as these particular Harma valves are all premium tested JJ's. Despite it not being a perfect replica of the Telefunken / Tesla E83CC it's still a bloody good valve for the money. I rate them.

[nick]

[quote name='umph' post='1142346' date='Feb 26 2011, 02:10 PM']oh another remake thats nothing like the original [/quote]

Sonically as well as aesthetically?

[voxpop]

[quote name='dood' post='1142339' date='Feb 26 2011, 02:04 PM']p.s. - who is geeky enough to try identify this one then?[/quote]

Think it's a general electric of sum sort... I use the the green label jan 5751 GE in my Vox.

[Dood]

[quote name='voxpop' post='1142643' date='Feb 26 2011, 06:34 PM']Think it's a general electric of sum sort... I use the the green label jan 5751 GE in my Vox.[/quote]


I posed the same question on my Facebook earlier and got another answer that is near as damn it right! It is indeed a GE. it's a NOS 5751 - manufactured in 1958! Again, for those of a geeky tendancy - it's a black plates, triple Mica. Can't wait to get the wee beast installed!

[umph]

[quote name='nick' post='1142590' date='Feb 26 2011, 05:54 PM']Sonically as well as aesthetically?[/quote]

aye. the originals are awesome.

[Owen]

I am being sucked into a valve vortex. I am fancying a Jule Amps Monique.

We need a valve bash so that those of us who are young in the ways of valves can plug in diferent valves and see what all the different ones do.

[umph]

[quote name='owen' post='1143291' date='Feb 27 2011, 01:39 PM']I am being sucked into a valve vortex. I am fancying a Jule Amps Monique.

We need a valve bash so that those of us who are young in the ways of valves can plug in diferent valves and see what all the different ones do.[/quote]
if it's up north i'll bring some of my horde

[Dood]

Well it has been a long day running A/B's in my Hartke head.

Some interesting results though not necessarily unexpected!

So here's how the day played out - I will do my best to not be biased! I ran up my amp head and left it for a good 20mins to settle. I spent about the next half an hour playing Bass with the EQ set to 'flat' and also bypassed the preamp so I could get a feel for the tone of the amp without a valve in the signal path at all. (Which in itself is quite a difference!)
After playing for a while I decided it was time to transplant. Out came the JJ ECC83 and in went the NOS GE 5751 pictured previously. Same thing again - leave for 20 mins and come back for a play.
I've repeated the above about four or five times throughout the day and so far I am happy with my thoughts on how the two valves sound. I realise that the JJ has accrued about 20 hours use, maybe more and the 5751 is considered NOS. I'd be interested to see how it compares in a few months time after being thrashed a bit!

The volume and tone controls stayed in the same position each time. However after the final run through I experimented with different settings to check for noise and what effect the valves had on the tone controls.



The results:

The first 3 differences I noticed straight away when I plugged in the 5751.

- A drop in overall output volume - Well, this I was expecting as the 5751 has a lower gain value. no problem. My basses have a very hot output which means that with the JJ valve my volume control on the amp is pretty low, even live. Still plenty of travel for that dial to go to add the volume back.

- A dramatic drop in background noise from the preamp. Especially when engaging the bright switch. I'm used to hearing additional hiss - yes, there still was, but greatly attenuated. - Even when I compensated for the drop in gain of the 5751 using the volume control to make up the output level - however, without that additional background hiss.

- Earlier in the thread I referred to the 'upward compression' of the 12AX7. Gotta say there was much less of this effect with the 5751. Myles Rose advised me this would be the case and I will see how I get on with it - or rather without it!! I think I miss it. Hmmmm

There were a few more subtle differences. I think, to my ears that the upper mids are less..errrm.. 'in your face'. I can't really describe it really. They're not scooped - just less obvious in comparison to the JJ. I feel this maybe because the JJ is meant to be a clone of a Telefunken/Tesla valve that is particularly good in microphone preamps as it accentuates frequencies in the female vocal range. I've read this many times and if this test is anything to go by, I'm inclined to agree. Not that my fiddling today has been even remotely technical!
The top end when ran up through my monitors is absolutely pristine. New strings sound just lovely! - I was expecting some additional bottom end prowess from the GE but I hadn't noticed a big difference if any. But lets give the lil fella a few hours to break in and then I'll go back and test again.

Ok, I've been playing CD's through the preamp for about two hours now, driving it fairly hard. I have to say that I *do* notice a difference in the sound. I'm afraid it's difficult to quantify the difference in terms of descriptions - but if I kept it really simple and said that the 5751 sounded clearer and more pleasing to my ear than the JJ then that's good enough. I'll try to expand on that if any of you can't get to sleep tonight and need something to do instead of counting sheep!!!!

That's about it for now - More rambling to come soon!

[edit] - Been playin music through the amp for a good few hours now and decided to drop my bass on for a bit of a jam. It appears that I now have a lot more bottom end than I did earlier! In a good way too!

[Owen]

OK valve people. All this valve talk reminded me that I had a spare valve that I bought because ...... ummm........

It is a Tung Sol Russian 12AX7, I put it in my Demeter HBP-1 this evening, replacing a EH one that was in there. Do I need to burn it in? How do I do that? On firing up it seemed less spongy than the EH. The EH was [i]almost[/i] compressing the initial transinent in any note. Compressing is too strong a word but I hope you get the drift. It's a whole new world!

[Dood]

Hey Owen - Funnily, I had a similar view of an EH valve I had in a pre once. Just use the valve as preamp as normal. I've read various reviews saying the likes of "oh it will need 8 hours of playing before it has settled" etc - but there's nothing else you have to do other than use it!

The Tung Sol is a good valve for sure! - I'm not sure on the situation now, but they were manufactured by EH at the Reflecktor factory in Russia - either before or after that the New Sensor corporation bought the name, but manufacture stayed at the same factory. Either way, it should reward you with a good tone. the EH yellow badged 12AX7's are Sovtek valves and usually the same models as GT, because both companies buy Sovteks in and rebadge them.