Fender HRD tone troubles

austint01

I have a Fender HRD that I'm struggling to get sounds I'm happy with anymore. I almost thought about flipping it for something else thinking it just wasn't for me but I'm sure I remember it sounding better than it currently does. Its an older Tweed covered one and has a cream back 65w in it.

EQ changes don't seem to affect the sound much. Bass and mid on 0 and it's still boomy and woofy. If I crank the treble and presence it goes from dull to brittle without anything in between. It just doesn't sound very even at any settings I try.

So far I've tried swapping v3 for v1 which did add some top end back. So I swapped the duller one into v2 because I don't use the second channel.

I also tried swapping power valves but the spares I know are worn and it didn't affect the sound.

Maybe I just need to revalve it? Or possibly something else that a tech needs to look at? Anyone had a similar experience?

MattFGBI

I would say that it probably needs the valves changing if you feel the sound is not as good as it once was. 
Have you always had that speaker in there? 

hywelg

Have to ask, how loud are you playing it.? I dont recall mine being boomy at low volume but it certainly came alive at 4½ on the volume.

impmann

Valves and speaker.

The speaker may not be suiting the sound of the amp - that could be contributing to the woofy-ness, especially if the cone is tired. Fender amps do tend to have more bottom end than some others - and if you are using a Gibson style guitar into it, this may emphasise it. 

Valves - I've found with my Mk3 that all the internet advice I've read hasn't worked for my use of the amp. I've found that it sounds *best* with factory fit Groove Tubes - everything else I've tried has detracted from the sound that I liked from it in the first place. If you're finding that changing the valves around improves things a bit, it sounds like they are either tired or not quite 'right' then that will have a negative effect on the sound. I'd also check the bias on the output valves - when I tried Ruby Tubes in there (yuk - another piece of dud advice on another forum) they definitely had a sweet spot when set a little warmer than the GTs. 

austint01

MattFGBI said:

I would say that it probably needs the valves changing if you feel the sound is not as good as it once was. 
Have you always had that speaker in there? 

No, it came with a Jensen P12N which had more bass actually. Had it in about a year now. It doesn't sound as good as the Jensen when absolutely clean, but the Creamback vastly improves dirt sounds.

austint01

MattFGBI said:

I would say that it probably needs the valves changing if you feel the sound is not as good as it once was. 
Have you always had that speaker in there? 

No, it came with an alnico Jensen P12N. It sounded nice on sounds, but brought out the fizz in any distortion pedal. It also had more bass than the Creamback. I remember at the time of swapping it, I thought it was a nice compromise for clean and dirt. It has definitely sounded better I'm sure (I think...). It's hard to draw comparisons over probably a year since the new speaker with no reference recordings or anything.

hywelg said:

Have to ask, how loud are you playing it.? I dont recall mine being boomy at low volume but it certainly came alive at 4½ on the volume.

I probably play it about 3 at gigs. It has definitely kicked in by then. This issue is affected quiet and loud though. I can notice it when its barely ticking over.

impmann said:

Valves and speaker.

The speaker may not be suiting the sound of the amp - that could be contributing to the woofy-ness, especially if the cone is tired. Fender amps do tend to have more bottom end than some others - and if you are using a Gibson style guitar into it, this may emphasise it. 

Valves - I've found with my Mk3 that all the internet advice I've read hasn't worked for my use of the amp. I've found that it sounds *best* with factory fit Groove Tubes - everything else I've tried has detracted from the sound that I liked from it in the first place. If you're finding that changing the valves around improves things a bit, it sounds like they are either tired or not quite 'right' then that will have a negative effect on the sound. I'd also check the bias on the output valves - when I tried Ruby Tubes in there (yuk - another piece of dud advice on another forum) they definitely had a sweet spot when set a little warmer than the GTs. 

I'm using a PRS McCarty. To my ears the Creamback actually rolled off bottom end compared the Jensen. I got the impression from reading it was a bit like a Greenback so doesn't have massive amount of bass.

Can bias drift? I'll check where its set. What value did you end up at? 

austint01

MattFGBI said:

I would say that it probably needs the valves changing if you feel the sound is not as good as it once was. 
Have you always had that speaker in there? 

No, it came with an alnico Jensen P12N. It sounded nice on sounds, but brought out the fizz in any distortion pedal. It also had more bass than the Creamback. I remember at the time of swapping it, I thought it was a nice compromise for clean and dirt. It has definitely sounded better I'm sure (I think...). It's hard to draw comparisons over probably a year since the new speaker with no reference recordings or anything.

hywelg said:

Have to ask, how loud are you playing it.? I dont recall mine being boomy at low volume but it certainly came alive at 4½ on the volume.

I probably play it about 3 at gigs. It has definitely kicked in by then. This issue is affected quiet and loud though. I can notice it when its barely ticking over.

impmann said:

Valves and speaker.

The speaker may not be suiting the sound of the amp - that could be contributing to the woofy-ness, especially if the cone is tired. Fender amps do tend to have more bottom end than some others - and if you are using a Gibson style guitar into it, this may emphasise it. 

Valves - I've found with my Mk3 that all the internet advice I've read hasn't worked for my use of the amp. I've found that it sounds *best* with factory fit Groove Tubes - everything else I've tried has detracted from the sound that I liked from it in the first place. If you're finding that changing the valves around improves things a bit, it sounds like they are either tired or not quite 'right' then that will have a negative effect on the sound. I'd also check the bias on the output valves - when I tried Ruby Tubes in there (yuk - another piece of dud advice on another forum) they definitely had a sweet spot when set a little warmer than the GTs. 

I'm using a PRS McCarty. To my ears the Creamback actually rolled off bottom end compared the Jensen. I got the impression from reading it was a bit like a Greenback so doesn't have massive amount of bass.

Can bias drift? I'll check where its set. What value did you end up at? 

austint01

hywelg said:

Have to ask, how loud are you playing it.? I dont recall mine being boomy at low volume but it certainly came alive at 4½ on the volume.

I probably play about 3 at gigs. I notice the issue both quiet and loud though.

I don't think I've ever had it at 4.5, you must rock pretty hard

austint01

impmann said:

Valves and speaker.

The speaker may not be suiting the sound of the amp - that could be contributing to the woofy-ness, especially if the cone is tired. Fender amps do tend to have more bottom end than some others - and if you are using a Gibson style guitar into it, this may emphasise it. 

Valves - I've found with my Mk3 that all the internet advice I've read hasn't worked for my use of the amp. I've found that it sounds *best* with factory fit Groove Tubes - everything else I've tried has detracted from the sound that I liked from it in the first place. If you're finding that changing the valves around improves things a bit, it sounds like they are either tired or not quite 'right' then that will have a negative effect on the sound. I'd also check the bias on the output valves - when I tried Ruby Tubes in there (yuk - another piece of dud advice on another forum) they definitely had a sweet spot when set a little warmer than the GTs. 

So what bias value did you end up at? There was a massive amount of variation of opinion online when I first re-valved it.

impmann

TBH, I can't remember - I'd need to measure it... but it now has the GTs back in there, so its a bit academic! The Rubys sounded different (bland and lifeless, in truth), so perhaps it is valve related.

MattFGBI

60ma is where the recommended bias is. 

ICBM

MattFGBI said:

60ma is where the recommended bias is. 

For both valves! Using the internal test point which is common to both, ie 30mA per valve.

Not 60mA per valve if using an external bias meter…

Just in case anyone who doesn't know that was reading it .

I doubt it's a power valve or bias issue though, it sounds more like preamp valves if it's valves at all.

A Tweed Hotrod Deluxe with a huge amount of low-end and a Creamback… hmmmm… I probably wouldn't mind one of those .

Danny1969

It's 60mV at TP30 isn't it ? is there a better current reading way to take it ?

austint01

With the amps age does it need a re cap? Would new caps affect the sound?

TheCount

12au7 in V1. Do this first - it's cheapest. Did it to my BDRI, was the difference between keeping it and getting shot of it

ICBM

Danny1969 said:

It's 60mV at TP30 isn't it ?

Yes, but it's best if you use the other end of the same resistor - the unlabelled solder point about 3/4" in front of it going directly into the amp, next to the end of the PCB - as the ground reference, and not any other ground. If you use (eg) the chassis, there is enough resistance between that point and the test point to thrown the reading off and give you an artificially high apparent reading, which will mean you bias the amp too cold and it can sound harsh.

Danny1969 said:

It's 60mV at TP30 isn't it ? is there a better current reading way to take it ?

Not really, unless you want to use either an external bias adaptor - which will do the same thing, but one valve at a time - or to meter the voltage drop across the OT, which is the most accurate but dangerous if you don't know what you're doing.

crunchman

60mV is the Fender recommendation and is pretty conservative.  A lot of people think it sounds better hotter.  I had mine hotter than that before I sold it.  If you work on the 70% of maximum plate dissipation that some people use as a guideline you can get up to 70mV plus depending on your plate voltage and the valves you are using.  You would need to find the specs of the power valves you are using though, and then do some sums.  I had Phillips 6L6WGB in mine which didn't have the max plate dissipation the 6L6GC, and the 5881 types might be slightly different again.

You are probably safe up to 70mV at the test point with any of the regular types unless you are seeing a really high wall voltage.  My old flat used to be about 246V the amp is specced for 230V so the plate voltage was about 456V rather than the 430V on the schematic.  I used to bias it so that it was slightly on the hot side at home.  When I was playing out it was probably running slightly cooler.

You don't have to go that high though.  The 70% of the max plate dissipation guideline is generally regarded as a maximum value.  If you like the sound at 60mV then leave it there as the valves will last longer. 

Having said that I don't think it sounds like the power valves are the most likely problem.  I would agree with what's been said above that it's more likely to be the preamp valves if it's valve related.

austint01

crunchman said:

60mV is the Fender recommendation and is pretty conservative.  A lot of people think it sounds better hotter.  I had mine hotter than that before I sold it.  If you work on the 70% of maximum plate dissipation that some people use as a guideline you can get up to 70mV plus depending on your plate voltage and the valves you are using.  You would need to find the specs of the power valves you are using though, and then do some sums.  I had Phillips 6L6WGB in mine which didn't have the max plate dissipation the 6L6GC, and the 5881 types might be slightly different again.

You are probably safe up to 70mV at the test point with any of the regular types unless you are seeing a really high wall voltage.  My old flat used to be about 246V the amp is specced for 230V so the plate voltage was about 456V rather than the 430V on the schematic.  I used to bias it so that it was slightly on the hot side at home.  When I was playing out it was probably running slightly cooler.

You don't have to go that high though.  The 70% of the max plate dissipation guideline is generally regarded as a maximum value.  If you like the sound at 60mV then leave it there as the valves will last longer. 

Having said that I don't think it sounds like the power valves are the most likely problem.  I would agree with what's been said above that it's more likely to be the preamp valves if it's valve related.

I think I'll start with pre amp valves and come back with hopefully some success. Thanks.

austint01

So the outcome of this was I just bought a full set of Tungsol preamp valves and JJ power valves.

I swapped in the Tungsols and it made no difference to sound or the noise floor.

I swapped in the JJs and the amp came back to life! I still need to re bias it but it was definitely the power valves!

Can't wait to get it sorted and crank it up to see how it sounds now