RAT Electronics Hot Rod Valve Special

JerkMoans

Comrades!

As I go through the perennial quest for perfect tone, whatever that is, I've had my head turned by a Victoria Amp and now I'm jonesing for it like crazy.

For years my main squeeze for home use has been this little Rat Amps modded Valve Jr.  Modded to heck by a fellow in Cornwall who sells on eBay as andydokken, and who has a ton of info up on his website at http://www.ratvalveamps.com/epiphone-valve-junior-sp-879237018

Thinking of moving it on to raise funds, but I haven't a clue how much it might be worth.  A quick search reveals one went for £295 on Fleabay a couple of years ago.  Anyone have any idea whether that's about right?  Too little?  Too much?  It's in immaculate condition, home use only.  If it's not worth much I'll probably hold onto it as it's a little gem, but if it is worth a few hundred squids I could use the cash for my next faithless betrayal of another bit of kit I swore I'd never sell  

All constructive comment, as ever, v gratefully appreciated.

Boromedic

Hey mate, I'd hang on to it to be fair but in order to help I found one went on eBay for £225 about 2 weeks ago:

Look at this on eBay  http://www.ebay.co.uk/itm/182735530882

Good luck with whatever you decide

JerkMoans

Boromedic said:

Hey mate, I'd hang on to it to be fair but in order to help I found one went on eBay for £225 about 2 weeks ago:

Look at this on eBay  http://www.ebay.co.uk/itm/182735530882

Good luck with whatever you decide

Thanks for that: hmmm.  At that money it's not really worth shifting - can let my daughter have it as to get anything half as nice would probably costs about twice as much!  Great research skills!

Boromedic

No worries and I agree with you that there is little point selling tbh, great little amps.

JerkMoans

In exciting news, my son’s mates have been using this to make a racket, and it now barely works - only one set of, er, settings can get a sound out of it.

my guess is that the valves need replacing, but where to start? Is this something a fellow can do for himself, or will it require biasing and similar voodoo qualities..?  Is it possible for a well meaning if ham fisted amateur to attempt without frying myself and immolating the house?

ElectricXII

It's cathode biased, so you should be able to just replace the valves and play.

JerkMoans

ElectricXII said:

It's cathode biased, so you should be able to just replace the valves and play.

Well that sounds quite reassuring...  I'll get the back off tonight and see what's needed.  If you never hear from me again, tell the fair Mrs Moans she can write on my tombstone 'It's the way he'd have wanted to go'  

Alex2678

Do you know which particular setting seems to bring it back to life or does it seem like a combination of the controls?

JerkMoans

Alex2678 said:

Do you know which particular setting seems to bring it back to life or does it seem like a combination of the controls?

Basically all switches down, in max position: Bias 3 / Gain 2 / Pentode makes it work.

Any variation leaves just Simon and Garfunkel's sound of silence...

Alex2678

Do the other controls work as normal when it’s set like that with the switches?

JerkMoans

Alex2678 said:

Do the other controls work as normal when it’s set like that with the switches?

Volume, tone etc?  Yeah: seem to... 

JerkMoans

JerkMoans said:

Alex2678 said:

Do the other controls work as normal when it’s set like that with the switches?

Volume, tone etc?  Yeah: seem to... 

Does that make a difference...?  

Alex2678

Just trying to eliminate things really, do you have any spare valves you could try or are you going to have to buy some?

JerkMoans

Alex2678 said:

Just trying to eliminate things really, do you have any spare valves you could try or are you going to have to buy some?

I’ll have to buy some. Given that I’ve had the thing >15 years without replacing any, it’s not such a chore  

Kittyfrisk

If it's a 12AX7 & EL84 that you need to debug the issue, I have some used but good ones that you can have?

JerkMoans

Kittyfrisk said:

If it's a 12AX7 & EL84 that you need to debug the issue, I have some used but good ones that you can have?

That's v kind.  

I am away in Oxford at the moment so can't pull the thing apart to check, but judging by the blurb and pictures at https://www.ratvalveamps.com/epiphone-valve-junior-sp-879237018 I think it's a 6L6 / 6V6 (whatever the difference may be) and either a ‘EL84’ (according to the text) or GZ34 or EZ81 (as per the pictures).  

Should be back in civilisation tomorrow night, so might have an investigative crack at it then, once I have rinsed the fetid stench of dreaming spires from my person  

andy_k

I have got a couple of Rat valve amps, an epi similar to yours, and a pair of Marshall class 5s, sweet little amps, and he no longer does any of them.
I'd be a bit wary of just replacing valves, if it's 15 years old it could be some of the electrolytic caps, and one bad thing could have a knock on effect, might be worth sending it to a decent Amp tech to have it properly serviced, at least it is small enough to post.
I think it is a 12ax7 el84 set up, with the GZ being used as the rectifier, and I'll have a peek at mine over the weekend, he did do some variations on this model, but I think it is worth hanging on to it, and keeping it working properly.

JerkMoans

andy_k said:

I have got a couple of Rat valve amps, an epi similar to yours, and a pair of Marshall class 5s, sweet little amps, and he no longer does any of them.
I'd be a bit wary of just replacing valves, if it's 15 years old it could be some of the electrolytic caps, and one bad thing could have a knock on effect, might be worth sending it to a decent Amp tech to have it properly serviced, at least it is small enough to post.
I think it is a 12ax7 el84 set up, with the GZ being used as the rectifier, and I'll have a peek at mine over the weekend, he did do some variations on this model, but I think it is worth hanging on to it, and keeping it working properly.

Thanks for the advice, and I agree re worth keeping it working.  Thought I'd just see if a valve swap solved the problem, and if it (then) seemed to be something more complex, seek a tech.

*edit* - and you’re absolutely spot on re the valve id  

JerkMoans

So, this is what one sees when one gets the back off, which was a swine of a job - either glue, or all the beer my son's mates have poured into it over the years meant the thing was stuck fast, and I practically had to get the bastard chisels to it...

All nice and neat inside.



And what of the valves?

First up, a 12AX7EH, dated July 2002.



Second up, an EL84/6BQ5, dated July 2001.



@Kittyfrisk is plainly a witch, and shall be receiving a PM, prontissimo   

Kittyfrisk

Received & actioned 
Be interested to hear how it all works out  

JerkMoans

Kittyfrisk said:

Received & actioned 
Be interested to hear how it all works out  

…as teams of specially trained operatives in flame retardant hazmat suits pick through a smouldering crater in N London…