HIWATT CUSTOM 100??

I use the same amp . I can only compare your price to what they sell for locally(Australia) and 300 euro sounds good. Normaly they sell for about $800-$1000AUD here - which is about 400-500euro I think.
They're an awesome sounding bass amp. they seem to work best with 4x12s , 2x15s or really efficient speakers.

 

Is it a 2 input or 4 input DR103? If it's a 2 input, they have more gain and are well suited for guitar. If it's a 4-input, they have more clean headroom and work great for bass. Plus you can jump the channels for a thicker tone. If it has Partridge transformers then you're set! The 2 input model would probably work fine and you could probably have it modded for more headroom (just don't go drilling new holes or you will ruin the value).

I have an old 4 input 100 that I use occasionally. It has been modded with a voltage doubler for the bias supply and an adjustable bias pot. I currently run mine with Svet 6550's and it punches nicely! If you decide to get the Hiwatt I highly recommend this bias supply mod or you may be going through tubes quickly due to excessive plate current.

Tapp

 

Listen to tapp, he speaks truth.

I've got a Sound City 200 that I converted into a 4-input Hiwatt DR201 clone. Sounds killer with my Rick 4001 through my 8x10... dimed.

 

Built in 1979, Kingston upon Thames factory.
Same model as the ones Pete Townsend was using at the time.
More of a guitar amp really but should be o.k. (ish) for Bass.
It's 24 years old now so most likely will need every tube and capacitor in it replaced for it to be reliable.
Take that into account and you are probably looking at more like 500 - 550 Euros total.

 

Paul is correct but not every capacitor needs replacing, just the electrolytics. Mine is an early 70's model and has the original mustard coupling caps and they sound fine. I would definitely let a knowledgeable tech look at the head for you if you decide to buy it. Again, I would want to try this one before I bought it. It may not have enough clean headroom for you in stock condition. Look around for a 4 input model.

Tapp

 

I don't know, man, for $300 (roughly 300 Euros, I think), I'd snatch that bad boy up pronto. Hiwatts are amazing, amazing amps. Matter of fact, I've heard zillions of guitarists with Marshalls of various vintages and they all sound like a toy compared to a Hiwatt. Marshalls ahve taht whiny mid-range thing, Hiwatts are big boxes of tone, tone, tone. When I play guitar, it's a Gretsch with Hi Lo trons through a 100W Hiwatt of the same era as the one you're looking at- sounds exactly like Malcolm Young.

tone- wise, Hiwatt is to Jaguar as Hartke is to Toyota. They're just not even the same thing at all. I mean, those Hartke's are OK heads. They work, they produce a signal, bass is reproduced by all legal definitions, but a Hiwatt is a beast of an amp.

 

New set of 4 (El34 tubes) = 90 Euros (at least)
New set of pre amp tubes (5) = 80 Euros (at least)
New power supply filter caps (at a minimum) = 90 Euros approx.
Re - Biasing + labour to do the work = 150 Euros (at least)
Price of amp = 300 Euros

Total = 710 Euros bottom line.

If,however,you KNOW what you are doing, you already have a good stock of tubes/spares it could be very attractive..... otherwise..probably not.