HH Scott 299C Amplifier

[Sparcki]

Hi i have just aquired a HH SCOTT229c amplifier.
The previous owners daughter was sellingit and said her father was an audio technician back in the day.
Everything is original including westinghouse valves and full user manual with schematic. 1 valve 7958 has been damaged so i will order a new 1 or do i need 2 as a matching pair?
Personally i would like a valve tech to look over it before i power it up.
It was made in 1961, caps look original!
Looking for recommendation/ suggestions for service repair as necessary.
i am based in uk Newcastle upon tyne.

[Edward Huggins]

I think you mean a 7058? If so, you are unlikely to need two. You must buy this valve, not the VERY NEAR equivalents viz: ECC83 or the 12AX7. A superb amp!

[snowman_al]

Do not be tempted to switch it on!
It is likely to be a USA 117 volt power transformer fitted. So unless it has been converted to a 240 volt type will need a step down transformer.
Being from the 60s and as you say original, it will need bringing back to life slowly and carefully.
Are you sure you have read the valve number correctly? Output types are normally 7591 or 7189 depending on exact model. And yes they really should be replaced in pairs.
I expect there is someone up your way who can help.
Welcome by the way

[Sparcki]

Hi snowman it is a UK version bought from a store in Soho Street London.
thanks for your input.

Original user manual with schematic and bill from Soho Street.

[Ed_Dinning]

Hi Sparki, it should perform very well when serviced, please avoid the temptation to try it when you get your new valve until it has been serviced

Ed

[Sparcki]

Hi Ed anyone local you could recommend for a service.
I am an electrician so would not attempt power up unless on a variac.

[Diabolical Artificer]

I could service it for you, I've done a 299C before, but I'm not local. It would need carefully packing and sending by courier. Unfortunately there's not many good UK valve techs in the UK, I don't know of any round you. I can advise on packing.

If not,you could have a go yourself,there's a bloke on Youtoob, XrayTony who has done a few HH Scott refurbs, worth checking out. That said it isn't a straight forward procedure,still,with some guidance it may be possible.

Andy.

[snowman_al]

Jez Arkless is in Morpeth.
Jez1234 on this forum if you look down at ''Repair and Restoration Services Offered''.

(The output valves from the instruction book picture are 7591 types.)

[Edward Huggins]

Originally Posted by Edward Huggins

I think you mean a 7058? If so, you are unlikely to need two. You must buy this valve, not the VERY NEAR equivalents viz: ECC83 or the 12AX7. A superb amp!

It would help all concerned if the OP could verify the above.

[Sparcki]

Hi all according to the user manual and schematic valves are as follows
Four 12AX7/ECC83
Two 6U8/ECF82
One 5AR4/GZ34
Four 7591

[Sparcki]

Note in user manual from Hermon Scott

[Sparcki]

Taken from manual

[Sparcki]

I have now found the original service manual

[Sparcki]

Valves

[qualityten]

Yep. 7591 power valves. There is a lot of knowledge and support for HH Scott amplifiers on the US website Audiokarma. Not to steer you away from discussion here, but as additional info. There are restoration threads and detailed question discussions, plus a database with schematics. The Scott site also has schematics, which might be useful though you have one for yours.

I have a 222C, which does need a step down transformer. Be interesting to see whether yours was adapted for UK mains.

[JonSnell]

The original Scott 299 was intended for the US market and the power transformer was wound for 110volts A/C 60HZ
The frequency doesn't matter.
I have refurbished three of these and from my understanding the valve list isshown on the list.
I have fitted a 12AY7 as the first pre amplifier as they are less noisy than a 12AX7 or ECC83.
As already discussed, check the mains supply and please check the main smoothing capacitors for electrical leakage.

[JonSnell]

An ECF80 is acceptable as a replacement for the ECF82 however, attention must be given to the balance pre sets.

[Sparcki]

Hi Thanks jonsnell , my thumbnail states my HH scott was adapted for uk as it states ingnore 115v in paperwork.
Have you serviced these hh scott amplifiers before?

[Herald1360]

Originally Posted by JonSnell

The original Scott 299 was intended for the US market and the power transformer was wound for 110volts A/C 60HZ
The frequency doesn't matter.

Shouldn't matter..... but if the TX design was pared to the bone, a 60Hz TX may overheat even fed with the correct primary voltage at 50Hz. Problem being core saturation on voltage peaks since the magnetising current at 50Hz will be 20% higher than at 60Hz.

[Sparcki]

Many Thanks to Ed Dinning, for fixing my Scott HH valve amp, I have been restoring a Goldring Lenco GL75 and together they sound sublime.
I will have to start off loading my other amps now this is running and sounding fantastic.
Cannot thank Ed enough.