HRD output valves

Emp_Fab

Once upon a time, I bought my HRD from new and it had blue Groove Tubes for power valves.  Not long after, one of them died, so I took the amp back to the shop and they just handed me a pair of Fender branded tubes.  (Actually Sovtek 5881's).  Since that day, I've not been happy with the tone.  It went very thick on the bottom end and rather boomy and I've just lived with it ever since.

I know strictly speaking, the output valves shouldn't really have a great influence on the tone, but I can't think of any other reason why it would suddenly change when the new tunes went in.  It's biased slightly conservatively too.

What would you suggest I replace the Fender 6L6 / 5881's with to get rid of the muddy bottom end and bring back some clarity ?  I mostly want to get it back so I don't have the EQ controls all at bonkers settings to try to compensate.

I don't mind replacing the preamp tubes too if there are any that jump out as big improvements over the stock ones.

Lastly, the bloody volume....  The sodding thing is uncontrollable with that huge jump in output between 0 and 2 on the dial.  It already has a log pot in there, so that mod is out.  I'm having to stick an an EQ pedal in the FX loop to attenuate it for band practice !  I'm wondering if a 12AT7 or AY7 would help with that instead ?

Any suggestions please ?  Ta muchly !

photek

Have you had it serviced? Mine sounded really flat and uninspiring when it needed caps replacing.

impmann

I run Groove Tube 6L6s in mine - it sounds great. I hated it with Ruby Tubes in there (I had a spare set that I needed to fit in a hurry) and it sounded very different. I then bought exactly the same valves as it had when it was new and *bingo* it was back to being great again.

thebreeze

This is the answer for the volume problem:

http://www.thefretboard.co.uk/discussion/117410/fender-hrd-blues-master-volume-module#latest

ICBM

Emp_Fab said:

What would you suggest I replace the Fender 6L6 / 5881's with to get rid of the muddy bottom end and bring back some clarity ?

EH, Tung-Sol reissues, or NOS Philips, GE or RCA.

Emp_Fab said:

I don't mind replacing the preamp tubes too if there are any that jump out as big improvements over the stock ones.

Pretty much anything but JJs or Sovteks.

Emp_Fab said:

Lastly, the bloody volume....  The sodding thing is uncontrollable with that huge jump in output between 0 and 2 on the dial.

What's it like between 1.4 and 1.5?



I know it's the most common complaint about these amps, but it baffles me a bit - yes, the taper is rather steep... but it's not a switch. If you turn the knob carefully, you can set it to the right volume.

If you*really* can't find a spot where it's the right volume no matter how small a turn you make, you already have the solution...

Emp_Fab said:

I'm having to stick an an EQ pedal in the FX loop to attenuate it for band practice !

Which also should give you the opportunity to tweak the EQ...

Emp_Fab said:

I'm wondering if a 12AT7 or AY7 would help with that instead ?

A little, but not much. The main reason for using different valves is to open up the tone and increase clean headroom, although it will reduce the gain as well which will make the controls slightly less sensitive. The best combination for me is a 12AY7 in V1 and a 12AT7 in V3, with the stock 12AX7 in V2.

Also, before you do anything else, re-set the mains voltage to 240V if it hasn't already been done - Fender supply them set to 230V. There are two push-connectors on the end of the PCB nearest the switches, P4 which has a white/black wire as stock and P10 which has a black wire. Swap these two. This will reduce all the internal voltages, reduce the volume and gain a tiny bit, and take away some of the 'shoutiness' of the tone, as well as making the amp run cooler and more reliably. You will probably need to adjust the bias if it's already on the cooler side.

impmann

This solves all the volume control issues, looks like it was built with the amp, and is the best investment you can make if you own an HRD, IMHO. I use mine at home all the time now...

http://thefretboard.co.uk/discussion/117410/fender-hrd-blues-master-volume-module#latest

crunchman

I put some NOS Phillips in my old HRD.  They did improve it, but changing the speaker made a bigger difference.  If you have the older version with the Eminence speaker, it would probably be a significant improvement if you can find a Weber 12F150.  The WGS equivalent of a C12N would probably do a similar job as well.

Emp_Fab

Thanks very much for the help folks.  It is greatly appreciated!

Emp_Fab

I've ordered a pair of NOS JAN Philips 6L6WGBs.  Let's see what they do..

stephen.wood125

Emp_Fab said:

I've ordered a pair of NOS JAN Philips 6L6WGBs.  Let's see what they do..

Watching this with great interest! 

mudslide73

Emp_Fab said:

I've ordered a pair of NOS JAN Philips 6L6WGBs.  Let's see what they do..

I had some of those in a Deville and they were magnificent. I had some Webers in there too mind.

hywelg

Emp_Fab said:

I've ordered a pair of NOS JAN Philips 6L6WGBs.  Let's see what they do..

Where from? I'd be interested in a pair for my OTS

exocet

hywelg said:

Emp_Fab said:

I've ordered a pair of NOS JAN Philips 6L6WGBs.  Let's see what they do..

Where from? I'd be interested in a pair for my OTS

They're readily available. Watford have them or they often appear on eBay.

Siemens / Philips / Sylvania - all the same thing as far as this particular valve is concerned. Apparently they were used by US Military up until 1980 so plenty of NOS stock.

 https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/260866814062

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/273164035171

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/112743318683

Emp_Fab

I got mine from https://www.langrex.co.uk/products/6l6wgb-philips-ecg-nos/

I finally got around to fitting them this afternoon.  Changed the voltage setting to 240 as per @ICBM s advice and biased them to 67ma (33.5ma each).  Tried it for the first time at rehearsals tonight.

My honest very initial opinion...  They are different.  All the settings I used to have no longer apply.  It initially sounded MUCH louder, but brighter at the top end - clearer - and the dynamics seemed more responsive.  I spent a lot of the night tweaking, trying to find tonal nirvana but not quite getting there.  Basically, I fought with the bloody thing all night.  I couldn't get over how LOUD it was.  It was bonkers.  I tried turning it up to see just how loud it would go but got halfway up the dial before it started feeding back - with the guitar strings muted.

I have no idea what the hell is going on !  It's early days, but it's a totally different amp.  I'm not sure if it's better yet mind ! - it's just a completely different amp !

ICBM

The dynamics and clarity - and usually more apparent volume - is quite normal for NOS valves compared to new-production, in my experience. I'm not totally sure why it should be so, but it's something I've always preferred - it's much easier to take that away than to get it when it isn't there.

Sounds like you may need to run it with the EQ pedal in the loop again.

gubble

I've a set of Mesa branded valves in there (no idea what they really are).

But they do sounded different and better to my ear than the groove tubes that were in there.

Philtre

I'll need to replace the output valves on my HRD iii soon. The ones in there are Groove Tubes marked "GT-6L6-CHP" Performance 9. Should I try to locate a pair of these or would standard JJ 6L6 do the trick?

crunchman

If you get the same Groove Tubes valves, with the same rating, then you can get away without rebiasing the amp.  If you use anything else then you should rebias.  It's not hard, but on the mark one HRD I had, it did involve taking the chassis out of the amp, and you will need a multimeter. 

If you are sensible it's safe enough, but make sure you know where the bias measurement point is, and don't randomly poke around inside.  The bias measurement point isn't high voltage but other parts are,  If the trimmer does need adjusting, again be careful with the screwdriver that you don't go touching other things.  You should use an electrical screwdriver with an insulated handle.  That way if you slip you won't get a nasty shock.

If you aren't confident doing it yourself, then you have three options.

1: get the matching Groove Tube valves, but you can probably get the same valves without the Groove Tubes badge for half the price.

2: get whatever valves you like and pay a tech to bias it.  Shouldn't cost a lot as it isn't a big job.  Might work out a bit more expensive than replacing the Groove Tubes valves though.

3: get whatever valves you like and just bung them in.  You will probably get away with it, but the life of the valves may be shortened, and if you do get some that run extremely hot, or extremely cold, it might not sound great.  If you bung them in, and the plates of the valve aren't glowing red, and the amp sounds ok, then you are probably ok.

Having said all that, unless you are completely impractical, it's worth learning to bias it yourself.  It's not hard to do, and you will get the best life out of your valves.

Philtre

I know how to bias valves, and have already checked and re-biased my HRD iii. Thanks for infos, though. :-)

My concern is getting the same tone that I have with the GTs marked as "Performance 9". The Groove Tubes website http://www.groovetubes.com/ has a GT rating system.

Haych

FWIW I find the T.A.D 6L6WGC to be a great tube.  I don't know what they start as before T.A.D put their stamp on but they always sound really good to me.