Let's Repair this 100w H/H Combo solid state amplifier 

@@TheGuitologist thanks Brad 🙏 Yes, they’re British. Thunderously loud with fantastic cleans. They were around in Australia in the 70s until by Laney took them over.

HAHA! What a great anecdote. Thanks for sharing

Great info, Jonathan!. I didn't know most of those users.

@@theguitaramptech and I think Bernard/Barney Sumner in Joy Division?

Thank you so much Larry.

Great comment, Kirk. You can tell a lot about a person’s musical taste by the amps they choose. I like your style. Both are great amps. be happy with your JC.

Thanks, Clay. The buzz is more than likely your filter capacitors. The volume dropout could be a few things that your tech can find. If the filter capacitors haven't been done on the Vibrolux, please get them changed. Ask him not to change any coupling capacitors unless he's 100% sure they are leaking. Let me know how you get on.

It has a mighty sound

I use mine to gig.... i run a modeller through it and use a 2 x12 v30 cab. I only ever use studio mode at that is ear spliting. The stage mode is so loud it physically stuns you!! Great amp of a bygone era

Cool Ed. I was also in a band in the 70s, where I had a Twin and the other guitar player had this model HH. The amp in the repair sounded even better than I remembered from my youth. I believe solid-state amps have their place in musical history when they stop trying to sound to sound like a valve amp.

@@theguitaramptech, here in the States, John Fogerty of Creedence Clearwater Revival became famous while playing through a solid state Kustom amp. The Lab Series amps have some fans (including BB King). Peavey made lots of solid state amps that were used by working musicians. I once had a Marshall Lead 20 that was a decent sounding SS amp except for cheesy low quality pots that were always a bit noisy even when new.

Your dad's probably my age :). I certainly prefer the H/H Clean sound. It makes for a great pedal platform. I hope the amp is still in the family.

Yep!

Perfect answer. You have demonstrated the beauty of individual tastes, Mario. For me, I loved the H/H cleans, but not the dirty. The other guitar player in the band of my youth had a H/H. It more than kept up with my Twin. Good memories of that H/H.

I didn't know that Tim. Thank you

Thank you Slavko!

@@theguitaramptech one question mate??? I have same model head HH, but does not come with reverb tank 👐, so can I install one like that amp you just fixed????

I mean upgrade it with the reverb ????

@@slavkomakarovski1158 that’s not so easy, Slavko. You need to add circuitry to drive the reverb tank, recover the wet sound, and then mix it back into the signal path. A huge job. If it was me, I wouldn’t do it. I would much prefer to have a nice reverb pedal. Cheaper. Easier. 😁

Thank you for your kind words. I’m happy that you’re getting something out of it. I just wish I had more time to do more regular videos. Too many amps to repair. 😂

Thanks Robert!

Wow. I have never seen one in the "flesh". I bet it sounds killer!

@theguitaramptech still probably needs a treble boost pedal in front of it, but at least it has bass, treble and presence,........and five channels so you and your four other guitarist buddies can play it like a musical huka pipe. I will be exploring it in the months to come.

@@thebenefactor6744 Excellent!!

You are Soooo right, Rick

They were pretty well made, Simon. We had similar Aussie made amps, but more tube amps in the 70's, like Wasp. I struck gold (not!) with my solid state Savage in 1975. It was loud...until it blew up, like all the other Savages..

Interesting; here in the States I've never seen or heard of an HH amp.

That would be awesome with the JBLs. Heavy as a block of concrete...but awesome. I have not heard any solid state amps with a great overdrive sound. Its just a totally different beast.

Yes. Less hum field and weight

Its interesting with the pronunciation differences. I haven't come across a Sessionette in Australia. Those transistor amps are great...until they break, and then its a battle to find those obsolete transistors.I currently have a JC120 on the bench with a very obsolete TA7122AP inline IC. None of the "reputable" suppliers have heard of it. I am buying 4 from China...wish me luck!

Not everyone used this pronuciation. Maybe a regional thing? I lived 25 minutes away from this firm when they were located in Cambridge in the 70's and they were certainly known as HH, but hey, what's in a name. Interestingly, the early version of the HH amps were not as bullet-proof as we might have hoped. Here's some very informative history from the website of MAJ Electronics who have first-hand experience working at HH and are the first port of call for spares/repairs/advice in the UK - check them out!. "2. Power amplifier failure. This was a big problem. The first units I ever saw in 1971-2 used Darlington based output stages similar to the second series TPA 50D and had driver pcb numbers AO 3073, (and AO3073/2 - second attempt, getting there...) I dont think the transistor based TPA AO3071 was ever used in the music range. The Darlington units were state of the art and well designed but turned out to be totally inadequate from a gigging point of view. There is a slight difference between a TPA 50D being used sensibly by a qualified BBC engineer using a controlled signal source connected to a correct speaker load using impeccable cables and young son hammering a Les Paul or a Strat at full power+++ and then some through an IC100 or S connected to as many speakers as he can find (Impedance? Wosthat?) using dodgy bell wire speaker leads and sellotape wrapped arcing sparking shit jack plugs. That slight difference is that it bangs and costs money to repair and doesn't do your reputation as a manufacturer any good. Ah.. So they changed to using a conventional bipolar output stage (AO 3103 pcb, through issues 2/3/5/6) and the problems grew less, but still didn’t quite go away. I maintained then and still do that the problem was not the actual output devices themselves, but the driver stages. The driver transistor part of a typical Darlington output transistor is fabricated on chip to supply the theoretic need of the output transistor part - not big enough in our thrash music world. The discrete TO-5 drivers used on the AO3103/5/6 were better but still only just adequate. In December 1974 the AO3103/7 pcb with its two grunt overkill RCA 40871/2 plastic driver transistors appeared across the range and the problem was minimised. The AS00014 pcb used in the VS and later units was a further development of this, getting rid of all the TO-5 devices and inheriting more sophisticated short circuit protection courtesy of the S500-D (Crown). This was a great move has proved to be a very reliable design."

HH for me always..... London since 1965

Great comment, Mike. I only monitor crossover distortion on in oscilloscope. My oscilloscope will read both Peak and RMS where my fluke will measure RMS values. So when I look at power output of an amplifier, I will either use the RMS value on the scope or fluke. They correlate extremely closely.

I found it with a Google search, Peter. Here you go: elektrotanya.com/hh-electronic_ic100_sch.pdf/download.html

@@theguitaramptech Thank you!

Hi Ken. First step is always check the fuse. Second step: check the voltages around your power supply. Disconnect stages where possible in your search to isolate the area where the fault lies. Such an old amp it could be anywhere, but I would focus on the power supply. . Just go through it step-by-step and I think you’ll find the problem.

@@theguitaramptech Thanks, mate. I'd checked the fuse & supply all the way to the transformer but the problem wasn't there; the amp was fine but there was a bad connection on the signal wire that had decided to work anyway for 3 weeks before deciding not to work at all! Sounds a lot better with a clean copper connection rather than a plastic sandwich......:)

@@k3np465 good detective work!

Thanks Sean. I’m sure you understand that I can’t advise you on an amp that I have not seen. There’s a good chance you may need to replace the filter capacitors. Replace like with like and take care with the polarity.

@@theguitaramptech thanks man, yeah I completely understand. Solid advice

Replacement caps are 4700uf in the main filter part. I used to repair lots of these amps with there ever growing fault list. Even the reverb tank needs replaced. These little amps worked great back in the day. The main power to3 transistors are npn types..

Thanks for the excellent question, Bryan. The not-so-excellent answer is "it depends". If you are gigging with the amps and you depend on reliability and performance, then I would definitely change the filter capacitors. If you are noodling around at home, you can get away with it for longer. It's like oil changes on a car. If you're racing, you change the oil after every race. If you are just going to the corner store, you can change your oil once a year. Good luck with the Trace. Great sounding amps.

@@theguitaramptech "Oh oh, the infamous Trace Elliott [bass] amp has f----d up again". David Lindley, at a gig with his band ElRayo-X around 1988 or 89 (bassist Jorge Calderon, who also played with Warren Zevon, was using one). I never heard of HH, must be an Aussie thing. H&K, yes....

Wow! A valve HH! Very cool. The best place to start is the power supply. Find a schematic and check that your voltages are close. Then try a different set of power valves (don't forget they will need to be biased).

@@theguitaramptech Thank you for your help..best regards.

Its always a difficult decision about amp saftey. I nearly always err on the side of increased safety. I decided to leave the illumination intact from memory.

I've just recapped my HH V-S Musician amp (1976) and had a reall challenge finding 4700 mf, 63v caps with a 35mm diameter to fit the original clips. Ebay was finally my reluctant friend providing a pair of Nichicon caps from China that have a good rap online and have worked well so far...

​@@andrewsutton7007please report back later on to know if they're worth it! 👍🏻

An excellent tip regarding the magnet! 🙏

@@theguitaramptech , I had to drill out some rivets on a McIntosh amp just the other day in order to remove the oval plates that held the original "twistlock" style of can-caps and install capacitor clamps like the ones on this amp. Unfortunately, the magnet only works if the rivets are steel and not if they're brass.....

Exactly right Ian. For 100Hz buzz look to filter caps. For 50Hz hum look to earthing, tubes, heater hum balance. Thanks 🙏

That does sound hot, but those transistors do seem to run very hot and keep on going. They're obsolete now so start searching for a matched replacement pair.. Check that you have the correct value of fuse for both of the output transistors. I think they're 4A, but please don't believe me.

@@theguitaramptech Hi and thanks for your reply, I dropped my amp off to my tech today, he's very good, so fingers crossed. Cheers Doug

Without having it on my bench, I can only give you general advice. First thing is to check your power supply voltages. As you've probably seen on some of my videos, I never go with just the uF value of a cap. I also check its ESR. If that's all good, its time to start tracing your sine wave input signal with an oscilloscope. Good luck.

@@theguitaramptech Thanks for the reply. The amp appears to have come to life with a continuous humming noise from the the speaker. There is nothing at all being generated from a guitar signal. Unfortunately I don't have an oscilloscope. I'm just checking voltages, resistance and capacitances with my meter. Everything appears to be ok. I'm wondering if those output transistors at the back under the plate might be the culprit?

I'd have to look up the schematics to be sure, but from memory they were bipolar.

As you know, it's impossible to accurately diagnose an amp remotely. However, check the Sustain footswitch socket. Your signal passes through it. Clean the contacts. Same story with the Channel1/2 switch. Good luck.

@@theguitaramptech Thanks for your tips. I will do that. Best regards.

I would agree with guitar amp tech...Us techs can't always give advice on working with live electronic equipment as a shock on the fingers is not nice!

I think you may be right with that recollection, Blusey. 👍

the first ones made actually had celestion alnicos in them..marc boland used one...most of them speakers were robbed by vox guys

You have discovered the main reason I don't like working on 70s and 80s solid state amps. Many of the semiconductor parts are obsolete and their equivalents are obsolete. You can literally waste hours in the search. Good luck, johnny.

@@theguitaramptech schematic say 2n3773 I'll try those but the capacitors are another story, having trouble locating 680uf 25v caps I found one dead and I haven't found any axial caps yet, and the other 2 are screw terminal, I could go schematics and try 4700uf but can only find pushin caps I suppose I can solder wires on but that would be in about 6-8 weeks when they arrive from China, Oh well good amp I want to keep it alive and well

@@johnnytheangel1 Don't worry about the 68uF. Pick a value that you can find up to 100uF. I always like to increase the voltage as a safeguard. Just make sure it physically fits. .

@@theguitaramptech unfortunately Jaycar in its infinite wisdom don't stock anything over 4700 so I got a couple of 4700uf at 63v and a couple 2n3773 transistors and we'll see how it goes

I would try either Element 14 (Farnell) or Antique Electronics Supply.

@@theguitaramptech Thank you I ordered it from Farnell and found out about linear versus log in the process! Courier is away more than the cost of the pot. Thanks.

@@michealhurley8412 yes, shipping costs plague us in Australia with every order. Americans don't know how good they've got it!

It’s a mystery still, Bob. The owner can’t shed any light.

Thanks for your msg. That’s too hard to diagnose remotely, Casey, with a description of pst. Check that you have no DC on any of the pots. If you do, do may have a leaky coupling cap.

@@theguitaramptech fair enough. I understand. I’ll explain a little more. I thought maybe it would be a very typical problem. It’s a quiet little crackle that’s happens every minute or two through just the woofer for about half a second. It’s a bi amped Yamaha hs7 studio monitor. Might be class d not sure. Anyway. That’s what it’s doin. I bought two of them used. The other speaker doesn’t do it. I have had this with other old hi fi amps, but I never knew what it was. I assumed old caps or something. These are only a few years old and I’m not going to fix them myself. I’ll just return them to guitar center and get different ones. Thanks!

HA!

@@theguitaramptech yeah man - those things are serious. Best to stick you your own music.

Well, I didn't know that, James. Thank you.

I know, right. Why would anyone clip out two capacitors, then return the amp to the customer? I’d love to find the answer to that one, Stefano

@@theguitaramptech I hate to fathom their reasoning.

@@theguitaramptech , I am working on a McIntosh MA230 hybrid integrated amp with solid state preamp and tube drivers and outputs. Somebody recapped it themselves from a "kit", after which it wouldn't work. They had miswired the entire power supply, installed one high voltage cap backwards ( it was bulging), forgot to hook up a ground reference for the negative side of the voltage doubler power supply, installed a capacitor backwards in the negative bias supply and reversed both the capacitor and diode for the low voltage supply to the solid state pre amp! They also cut a bunch of wires to the tone controls and the rotary wafer-type input selector switch in order to get the preamp board out for recapping, and then they spliced the wires back together incorrectly (colorblind perhaps?), so that once I fixed the power supply the unit powered up but the treble control worked backwards and had loud hiss on one channel. I sorted that out, but it still has an intermittent issue on one channel.....😖