Robin Wood Amps?

Acdeezee86

Anyone had any experiences with Robin Wood Amps? They seem to specialise in upcycled versions of classic amps: https://www.robinwoodamps.co.uk/ - just from the images they look solid and very sensibly priced!

 I've seen a few posts here and there, but would love to hear any other views.

Dave_Mc

I'm no amp tech so I can't comment on the build quality but I've got his 5F2-A Princeton clone, and to my ears it sounds killer. I've got a Jensen P8R in mine. EDIT: You're probably already aware but if not just bear in mind that even the 5 watters will be very loud even with a low efficiency speaker like a Jensen P8R.

ecc83

I know nothing of the guy and I am sure his amps are perfectly fine. However, reading his site info he trots out the old saw that "the amps retain lethal voltages even after switch off" Well yes! They do/did if you let them but it is a trivial bit of extra work to fit a drain resistor across the main capacitor that will ensure the volts die to zero in under a minute.

Dave.

mrkb

Some of the yellow cabling on the LHS of this image looks manky - is he using reclaimed cables?

ecc83

mrkb said:

Some of the yellow cabling on the LHS of this image looks manky - is he using reclaimed cables?

Magnifying that image, the whole thing looks rather 'grubby' but then these are "reclaimed" amplifiers and so long as they meet spec' and are safe (PAT cert' with each one I hope?) who minds a bit of muck?

And! On safety, I DO wish people would boot and sleeve mains connections!

Dave.

bertie

any else read this as "Robin Hood"  amps ?   

fretfinder

bertie said:

any else read this as "Robin Hood"  amps ?   

Yes I did!

“Feared by the bad, loved by the good…!” 

Alex2678

mrkb said:

Some of the yellow cabling on the LHS of this image looks manky - is he using reclaimed cables?

I think those are coming from the transformers and he does definitely use reclaimed transformers, though I think you can pay extra for him to use new ones

bertie

on his website he makes it clear he uses reclaimed transformers and speakers and they will have an unknown life expectancy. 

Acdeezee86

Thanks all for the comments - good to rely on better trained eyes and minds than mine!

Just to add that in an email exchange he did ask whether I was ok with reclaimed transformers, valves and speakers, which I suppose means that new ones are an option.

goldtop

ecc83 said:

mrkb said:

Some of the yellow cabling on the LHS of this image looks manky - is he using reclaimed cables?

Magnifying that image, the whole thing looks rather 'grubby' but then these are "reclaimed" amplifiers and so long as they meet spec' and are safe (PAT cert' with each one I hope?) who minds a bit of muck?

And! On safety, I DO wish people would boot and sleeve mains connections!

Dave.

I know it's convention, but surely it only makes sense when the rest of the device is low voltage? 

In a valve amp where there's high voltages everywhere, it's a potentially (sic) misleading to insulate the mains-side connections and think 'job done'.

theterracat

Great to see people chatting about Robin Wood Amps. I can share my own direct experience:  in terms of service level, and crafting a unique product, I think they offer amazing value for money.  I had them build me a custom 5f10 (Fender Harvard tweed era circuit) early last year. That amp was not on his 'menu' but he was willing to give it a go after I had a nice chat with him, and from my perspective the result has been excellent. I was playing it last night actually, and it's a lovely old warm set of tones. I was happy for him to use mostly upcycled components -- except for the transformer, because apparently the one for this circuit was quite hard to source used/upcycled. Picture below.

Comms during the build were great; he gave me sporadic updates, and occasionally asked about design choices. The reclaimed wood cabinetry that I chose for him to use (he gave me a bunch of options) has a unique look that I really dig and I was pleased with his work. Would happily work with him again. Particularly if I wanted an old Champ or Princeton circuit, this would be the way I would do it.

goldtop

Using recycled/reclaimed/salvaged components is a great idea. It's not scalable, of course, and each project must present its own headaches (a.k.a. opportunities), so what he's doing is commendable. And probably a lot more rewarding than cranking out identikit amps.

ecc83

goldtop said:

ecc83 said:

mrkb said:

Some of the yellow cabling on the LHS of this image looks manky - is he using reclaimed cables?

Magnifying that image, the whole thing looks rather 'grubby' but then these are "reclaimed" amplifiers and so long as they meet spec' and are safe (PAT cert' with each one I hope?) who minds a bit of muck?

And! On safety, I DO wish people would boot and sleeve mains connections!

Dave.

I know it's convention, but surely it only makes sense when the rest of the device is low voltage? 

In a valve amp where there's high voltages everywhere, it's a potentially (sic) misleading to insulate the mains-side connections and think 'job done'.

In a modern PCB valve amp it is possible to insulate most of the high voltage points although a t**t with a screwdriver can still catch a jolt if they really try! I do agree that such protection is impossible with turret board construction but surely we should make safe as much as we can? In any case a well booted chassis is neater and LOOKS like somebody cared?

Dave.

ecc83

goldtop said:

Using recycled/reclaimed/salvaged components is a great idea. It's not scalable, of course, and each project must present its own headaches (a.k.a. opportunities), so what he's doing is commendable. And probably a lot more rewarding than cranking out identikit amps.

I agree and despite my small reservations I think this is an excellent idea. I am immensely keen on recycling and using resources better. These amplifiers can be repaired almost ad. inf. or at least as long as valves can be economically sourced.

Dave.

goldtop

ecc83 said:

goldtop said:

ecc83 said:

mrkb said:

Some of the yellow cabling on the LHS of this image looks manky - is he using reclaimed cables?

Magnifying that image, the whole thing looks rather 'grubby' but then these are "reclaimed" amplifiers and so long as they meet spec' and are safe (PAT cert' with each one I hope?) who minds a bit of muck?

And! On safety, I DO wish people would boot and sleeve mains connections!

Dave.

I know it's convention, but surely it only makes sense when the rest of the device is low voltage? 

In a valve amp where there's high voltages everywhere, it's a potentially (sic) misleading to insulate the mains-side connections and think 'job done'.

In a modern PCB valve amp it is possible to insulate most of the high voltage points although a t**t with a screwdriver can still catch a jolt if they really try! I do agree that such protection is impossible with turret board construction but surely we should make safe as much as we can? In any case a well booted chassis is neater and LOOKS like somebody cared?

Dave.

FWIW I've never seen a PCB with touch-proof insulation added throughout the circuit? It'd exasperate most amp techs, making maintenance and diagnostics unnecessarily time consuming and expensive.

I'm mostly concerned by the false sense of security given by an inconsistent approach to HV insulation. 

ecc83

goldtop said:

ecc83 said:

goldtop said:

ecc83 said:

mrkb said:

Some of the yellow cabling on the LHS of this image looks manky - is he using reclaimed cables?

Magnifying that image, the whole thing looks rather 'grubby' but then these are "reclaimed" amplifiers and so long as they meet spec' and are safe (PAT cert' with each one I hope?) who minds a bit of muck?

And! On safety, I DO wish people would boot and sleeve mains connections!

Dave.

I know it's convention, but surely it only makes sense when the rest of the device is low voltage? 

In a valve amp where there's high voltages everywhere, it's a potentially (sic) misleading to insulate the mains-side connections and think 'job done'.

In a modern PCB valve amp it is possible to insulate most of the high voltage points although a t**t with a screwdriver can still catch a jolt if they really try! I do agree that such protection is impossible with turret board construction but surely we should make safe as much as we can? In any case a well booted chassis is neater and LOOKS like somebody cared?

Dave.

FWIW I've never seen a PCB with touch-proof insulation added throughout the circuit? It'd exasperate most amp techs, making maintenance and diagnostics unnecessarily time consuming and expensive.

I'm mostly concerned by the false sense of security given by an inconsistent approach to HV insulation. 

With a PCB it is perfectly possible to have all the HT caps 'solder side'. The transformer wires come down to 6mm spades with insulating boots. Valve holder pins are also solder side. Thus, from the top of the chassis you have to be a bit stupid to cop a jolt. Diagnosis is not a problem, cathode and anode Rs can be accessed with a test probe but not easily with a digit. A needle sharp probe will pierce insulation.

Of course, further investigation will involve removal of the PCB and so we are then in the province of the expert tech with his/her training and experience of staying alive!

Been there, done it, got the T shirt.

Dave.

ICBM

The justification for sleeving just the mains connections is that if you're working on the amp, it's quite easy to switch off and forget that it's not completely safe because the mains connections are still live. *I know* you should never do anything like that, but people forget the simplest things sometimes, and when the power light is off it can trick you into a false sense of safety. Not that I've ever had anything like that happen of course - scout's honour.

If nothing else, even if you've turned off the wall socket - but not pulled the plug, which may be intentional so the amp remains earthed - the neutral is still normally connected (mains socket switches are single pole), and if you touch that it can be enough to trip the RCD in the distribution box, which is quite annoying when your bench light and the computer you're using for circuit diagrams and playing background music are all on the same circuit.

(NB, I was never in the scouts...)

Dave_Mc

bertie said:

any else read this as "Robin Hood"  amps ?   

I could be wrong, but I sort of assumed that was kind of the point? It's not his name (as far as I recall, anyway!), at any rate, so I'm assuming there's some reason behind the choice of name...

bertie said:

on his website he makes it clear he uses reclaimed transformers and speakers and they will have an unknown life expectancy. 

FWIW he told me that he'd actually had fewer problems with the used transformers than the new ones!

I do suspect it's worth going with new speakers, though- if you're after a specific vintage circuit it makes sense to go with the speaker it's "meant" to be used with to get it to sound "right".

theterracat said:

Great to see people chatting about Robin Wood Amps. I can share my own direct experience:  in terms of service level, and crafting a unique product, I think they offer amazing value for money.  I had them build me a custom 5f10 (Fender Harvard tweed era circuit) early last year. That amp was not on his 'menu' but he was willing to give it a go after I had a nice chat with him, and from my perspective the result has been excellent. I was playing it last night actually, and it's a lovely old warm set of tones. I was happy for him to use mostly upcycled components -- except for the transformer, because apparently the one for this circuit was quite hard to source used/upcycled. Picture below.

Comms during the build were great; he gave me sporadic updates, and occasionally asked about design choices. The reclaimed wood cabinetry that I chose for him to use (he gave me a bunch of options) has a unique look that I really dig and I was pleased with his work. Would happily work with him again. Particularly if I wanted an old Champ or Princeton circuit, this would be the way I would do it.

That looks very like mine! Except yours is probably a little bigger. Awesome. I suspect you're why he now offers the Harvard... and probably the brown panel Princeton, too.

I'd totally work with him again too, I just haven't got round to it (I'd need to see if he could fit VVR, even the Princeton is pretty loud!). I agree with you about the circuits, and it's pretty much what he says too- it's a great way to get to try a classic circuit to see if you like it without having to spend thousands. Quite a lot of these classic circuits aren't even available new from most manufacturers, so unless you live close to a shop which stocks some very specific boutique manufacturers' amps, it's hard to even get to try the things...

earwighoney

I have one of his brown panel Princetons.  Superb amp.

Dave_Mc

earwighoney said:

I have one of his brown panel Princetons.  Superb amp.

Oh wow, nice! What's the difference between the brown panel Princeton and the tweed Harvard? I had a look at the schematic a while back and they looked pretty similar apart from the tremolo on the Princeton (and the 6AT6 in the Harvard, but I think it's more of less half of a 5751, right?)...