HH TPA series Power Amplifiers. - Page 6 - UK Vintage Radio Repair and Restoration Discussion Forum

teetoon · 19th Sep 2015, 9:49 pm

Hello Kamran. I will try to answer some of your questions but please remember I am not an amp designer, I just repair them using the exact parts as were original.

There is nothing rare about the transistors and a quick look on ebay shows plenty of suppliers offering worldwide postage at reasonable prices.

The TPA 100D uses, 2N3440, 2N5415, BC107c, BC177c and outputs are either 2N3773 or MJ15003. All these are still available.

Diodes on your board all seem to be IN4148. If you look at the original board pic I posted you will see there is a zener diode to the bottom left hand side. I think it was 24v. Not sure what difference it makes that you don't seem to have this.

The circuit board tracks in the picture are continuous, there are no breaks or modifications. That particular amp did not appear to have been repaired so was very reliable for a 40+ year old amp.

Also the circuit diagram does not have voltage reference points marked.

I wouldn't want to discourage you but, if I was making a copy of this amp, it would be an exact copy. Especially as all parts are still available.

Hope this doesn't sound harsh

. I respect your enthusiasm but I think you are making this overly complicated by trying to modify a proven design which was made to be ultra reliable and in constant use for broadcast monitors. Some of these amps were in use 24/7 and most of the ones I had were still using their original parts.

In summary, I think you need to look for an original circuit board and copy that.

David.

kamran yousaf · 21st Sep 2015, 9:25 am

Sir David,

Bundle of thanks for the such great help in this regard I have covered a lot of issues and now my amp is working almost fine. But its was a little bit difficult to read the schematic because it was not in a good resolution and If i could be able to read the Voltages mention on different points in () then it would be more helpful anyhow now I am much confident about this amp. If you can email me its schematic by your mob or computer at *Removed by Moderator* then it can answer my remaining questions Thanks.

kamran yousaf · 30th Sep 2015, 8:25 am

Dear All,

I have used a preamp using NE5532 with TPA 100D it gives me the exceptional response.

kamran yousaf · 16th Dec 2015, 8:44 am

Sir David,

Good Morning hope you are good and busy in your daily commitments but i have a question after a long time i hope you will not mind it please actually a just wants your feed back about the comparison of TP100D and MA100 in the sense of power quality input and out put response Thanks.

teetoon · 17th Dec 2015, 12:42 am

Hello Kamran.
As to comparison between the TPA 100D and MA 100, they are a completely different animal.
The TPA 100D was designed as a monitor amplifier for use in broadcast environments etc and delivers 100 watts into 15 ohms and more than 225 watts into 4 ohms. To my ears the sound quality is very good with only a small amount of crossover distortion probably dependant on the matching of the output devices ( 4 x 2N3773 ).
The MA 100 is actually a mixer amplifier but for the sake of comparison, a power amp only version was available known as the S 130. These are 120 watts max into 4 ohms ( only 2 x 2N3773 outputs ), so less than half the power of the 100 D. These amps were part of the HH musician range and as such did not to my ears offer the same quality.
I used a pair for my early disco system and they could best be described as a bit clinical and not at all warm in the bass. Very reliable though even when run really hard. They got very hot too.
I still have both types and comparing them in recent years they are just as I remember. The TPA's sound lovely and the M series amps sound like a reasonable 70's PA. Can't knock the reliability factor though.

David.

kamran yousaf · 5th Jan 2016, 10:43 am

My Dear All,

Will you(Anyone) please share S500D Front and back of Power amp PCB in high resolution Thanks.

kamran yousaf · 9th Feb 2016, 7:31 am

Quote:

Originally Posted by teetoon

I still have both types and comparing them in recent years they are just as I remember. The TPA's sound lovely and the M series amps sound like a reasonable 70's PA. Can't knock the reliability factor though.

Sir David,

I have great wish that I wants to see you in my life, And if you can help/Guide me in this regard I will be very grateful Thanks.

NelsonUsi · 25th Feb 2016, 12:47 am

Hello Kamran and all other members (from new join)

The S 500-D has three PCBs, 1x input module and 1 each side of heat sinks supplying (live) to the bases of the o/p transistors eg. (heatsinks are live).

What is the problem you have, it would help get you the information you need.
I have access to all diagrams for this amp as well as the published user manual.

Also there are two small difference versions of the S 500-D. Early version have a 7pin DIN port above Channel 2 (right hand) line input (1/4inch jack) at rear of amp. Later version, no DIN port. Basic diagram is identical in both.

I use 4 of 500-D for bass and sub bass (below 40HZ) C-Audio for mid and top.
Presently struggling myself to find the cause of a nasty intermittent full on 62V DC on one channel of one amp, but glad to help if I can.

Regards
Nelson Usi

kamran yousaf · 2nd Jun 2016, 11:23 am

Sir,

Can you just share details of its power amp, schematic , PCB, up and down snap shots Thanks.

kamran yousaf · 2nd Jun 2016, 11:34 am

Quote:

Originally Posted by teetoon

Anyway here are some pics of the TPA 100D and a pic of the schematic. Sorry I don't have a scanner>

How are you Mr. David,

Can you please upload schematic Image in high resolution (zip file), definitely you will have a nice camera or mobile phone now Thanks.

Edward Huggins · 4th Jun 2016, 10:50 pm

I remember when these HH amps were the Dog's Bxxxxxx! I think they also had a version with a crude circuit in the AF stage that introduced a form of 2nd harmonic distortion to make then sound, er, "Valvey".... Edward

Valvepower · 5th Jun 2016, 9:21 pm

Hi,

I figure that was the VS Musician series of amplifiers. This range was supposed to be the death knell for the valve guitar amplifier – oh well better luck next time

Originally the Valve sound module was potted so you couldn’t see the ingenious stuff inside, but as time and tide went on the replacement modules appeared without being potted! For my sins I fixed these things in the local music Shop back in the 70’s and early 80’s as they were an HH dealer. I remember a few of the potted dud modules gathering dust on the shelf in the workshop, as they had a penchant for going belly-up on a regular basis.

I found the circuit of the valve sound module on the Vintage Amps Forum – thanks to Bojaman in 2007. Oh well it was a FET amplifier and some diode clipping - wot no ECC83’s

The EQ was a standard cut/boost LC ‘graphic’ type equalizer circuit. Rory Gallagher in his early days used a similar LC circuit in the guise of the Hawk booster.

I figure the J174 FET feeding the master volume pot is some sort of limiter/clamp? Or is there something missing to make it a switch?

Terry.

ITAM805 · 5th Jun 2016, 11:30 pm

Thanks Terry, I'd often wondered what the 'secret' was in depths of the potted box in the VS range, not that they sounded like a valve amp to me ! My last gigging amp that I sold a couple of years ago was a monster V-S Bassamp 115 combo that really did give me a hernia

Extremely loud for tranny combo, the guts being just a standard HH 100W chassis. It was probably due to the 15" speaker and enclosure design.

I bought a Bass Machine which was a kick*ss 250W Mosfet job, to replace the aforementioned combo but it went wrong on it's first gig and I retired before I got round to repairing it !

Diabolical Artificer · 6th Jun 2016, 6:31 am

Kamran, I have the S500-D and can take a few pics for you, give me a few days though. Not sure if I can do track side of PCB, that means taking the amp apart. Got a schematic for the power amp somewhere,but the not for the pre, which is a plug in. TT/David probably does'nt have one.

Do you have an S500-D or are you busy making HH clones out there in India? : ) The V series are worth looking at, all the way up to the V900. Big, very, very heavy amps.

Andy.

kamran yousaf · 7th Jun 2016, 10:10 am

Sir,

You are right and I am from Pakistan.

IamLars · 16th Jun 2016, 7:53 pm

Hi,

I have had a TPA 50-D for some time but I have never tested it. However, the "slots" for fuses in the front panel are empty (1 x 2.5A AC , and 2 x 6.3A DC). Can anyone give me a specification of these fuses (Voltage , size/type) so that I can source them somehow.

Thanks,

/Lars

19th Sep 2015, 9:49 pm	#101
teetoon Heptode Join Date: Dec 2010 Location: Barnstaple, N.Devon, UK. Posts: 557	Re: HH TPA series Power Amplifiers. Hello Kamran. I will try to answer some of your questions but please remember I am not an amp designer, I just repair them using the exact parts as were original. There is nothing rare about the transistors and a quick look on ebay shows plenty of suppliers offering worldwide postage at reasonable prices. The TPA 100D uses, 2N3440, 2N5415, BC107c, BC177c and outputs are either 2N3773 or MJ15003. All these are still available. Diodes on your board all seem to be IN4148. If you look at the original board pic I posted you will see there is a zener diode to the bottom left hand side. I think it was 24v. Not sure what difference it makes that you don't seem to have this. The circuit board tracks in the picture are continuous, there are no breaks or modifications. That particular amp did not appear to have been repaired so was very reliable for a 40+ year old amp. Also the circuit diagram does not have voltage reference points marked. I wouldn't want to discourage you but, if I was making a copy of this amp, it would be an exact copy. Especially as all parts are still available. Hope this doesn't sound harsh. I respect your enthusiasm but I think you are making this overly complicated by trying to modify a proven design which was made to be ultra reliable and in constant use for broadcast monitors. Some of these amps were in use 24/7 and most of the ones I had were still using their original parts. In summary, I think you need to look for an original circuit board and copy that. David.

21st Sep 2015, 9:25 am	#102
kamran yousaf Triode Join Date: Sep 2015 Location: Lahore, Punjab, Pakistan. Posts: 25	Re: HH TPA series Power Amplifiers. Sir David, Bundle of thanks for the such great help in this regard I have covered a lot of issues and now my amp is working almost fine. But its was a little bit difficult to read the schematic because it was not in a good resolution and If i could be able to read the Voltages mention on different points in () then it would be more helpful anyhow now I am much confident about this amp. If you can email me its schematic by your mob or computer at Removed by Moderator then it can answer my remaining questions Thanks. Last edited by AC/HL; 21st Sep 2015 at 11:57 am. Reason: Exchange of email address via PM please

30th Sep 2015, 8:25 am	#103
kamran yousaf Triode Join Date: Sep 2015 Location: Lahore, Punjab, Pakistan. Posts: 25	Re: HH TPA series Power Amplifiers. Dear All, I have used a preamp using NE5532 with TPA 100D it gives me the exceptional response.

16th Dec 2015, 8:44 am	#104
kamran yousaf Triode Join Date: Sep 2015 Location: Lahore, Punjab, Pakistan. Posts: 25	Re: HH TPA series Power Amplifiers. Sir David, Good Morning hope you are good and busy in your daily commitments but i have a question after a long time i hope you will not mind it please actually a just wants your feed back about the comparison of TP100D and MA100 in the sense of power quality input and out put response Thanks.

17th Dec 2015, 12:42 am	#105
teetoon Heptode Join Date: Dec 2010 Location: Barnstaple, N.Devon, UK. Posts: 557	Re: HH TPA series Power Amplifiers. Hello Kamran. As to comparison between the TPA 100D and MA 100, they are a completely different animal. The TPA 100D was designed as a monitor amplifier for use in broadcast environments etc and delivers 100 watts into 15 ohms and more than 225 watts into 4 ohms. To my ears the sound quality is very good with only a small amount of crossover distortion probably dependant on the matching of the output devices ( 4 x 2N3773 ). The MA 100 is actually a mixer amplifier but for the sake of comparison, a power amp only version was available known as the S 130. These are 120 watts max into 4 ohms ( only 2 x 2N3773 outputs ), so less than half the power of the 100 D. These amps were part of the HH musician range and as such did not to my ears offer the same quality. I used a pair for my early disco system and they could best be described as a bit clinical and not at all warm in the bass. Very reliable though even when run really hard. They got very hot too. I still have both types and comparing them in recent years they are just as I remember. The TPA's sound lovely and the M series amps sound like a reasonable 70's PA. Can't knock the reliability factor though. David.

5th Jan 2016, 10:43 am	#106
kamran yousaf Triode Join Date: Sep 2015 Location: Lahore, Punjab, Pakistan. Posts: 25	Re: HH TPA series Power Amplifiers. My Dear All, Will you(Anyone) please share S500D Front and back of Power amp PCB in high resolution Thanks.

25th Feb 2016, 12:47 am	#108
NelsonUsi Retired Dormant Member Join Date: Feb 2016 Location: Tunbridge Wells, Kent, UK. Posts: 1	Re: HH TPA series Power Amplifiers. Hello Kamran and all other members (from new join) The S 500-D has three PCBs, 1x input module and 1 each side of heat sinks supplying (live) to the bases of the o/p transistors eg. (heatsinks are live). What is the problem you have, it would help get you the information you need. I have access to all diagrams for this amp as well as the published user manual. Also there are two small difference versions of the S 500-D. Early version have a 7pin DIN port above Channel 2 (right hand) line input (1/4inch jack) at rear of amp. Later version, no DIN port. Basic diagram is identical in both. I use 4 of 500-D for bass and sub bass (below 40HZ) C-Audio for mid and top. Presently struggling myself to find the cause of a nasty intermittent full on 62V DC on one channel of one amp, but glad to help if I can. Regards Nelson Usi

2nd Jun 2016, 11:23 am	#109
kamran yousaf Triode Join Date: Sep 2015 Location: Lahore, Punjab, Pakistan. Posts: 25	Re: HH TPA series Power Amplifiers. Sir, Can you just share details of its power amp, schematic , PCB, up and down snap shots Thanks.

4th Jun 2016, 10:50 pm	#111
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: HH TPA series Power Amplifiers. I remember when these HH amps were the Dog's Bxxxxxx! I think they also had a version with a crude circuit in the AF stage that introduced a form of 2nd harmonic distortion to make then sound, er, "Valvey".... Edward

5th Jun 2016, 9:21 pm	#112
Valvepower Octode Join Date: Aug 2008 Location: Rayleigh near Southend-On-Sea, Essex, UK. Posts: 1,878	Re: HH TPA series Power Amplifiers. Hi, I figure that was the VS Musician series of amplifiers. This range was supposed to be the death knell for the valve guitar amplifier – oh well better luck next time Originally the Valve sound module was potted so you couldn’t see the ingenious stuff inside, but as time and tide went on the replacement modules appeared without being potted! For my sins I fixed these things in the local music Shop back in the 70’s and early 80’s as they were an HH dealer. I remember a few of the potted dud modules gathering dust on the shelf in the workshop, as they had a penchant for going belly-up on a regular basis. I found the circuit of the valve sound module on the Vintage Amps Forum – thanks to Bojaman in 2007. Oh well it was a FET amplifier and some diode clipping - wot no ECC83’s The EQ was a standard cut/boost LC ‘graphic’ type equalizer circuit. Rory Gallagher in his early days used a similar LC circuit in the guise of the Hawk booster. I figure the J174 FET feeding the master volume pot is some sort of limiter/clamp? Or is there something missing to make it a switch? Terry. Attached Thumbnails Last edited by Valvepower; 5th Jun 2016 at 9:38 pm. Reason: Triping Errot

5th Jun 2016, 11:30 pm	#113
ITAM805 Nonode Join Date: Jul 2010 Location: Folkestone, Kent, UK. Posts: 2,172	Re: HH TPA series Power Amplifiers. Thanks Terry, I'd often wondered what the 'secret' was in depths of the potted box in the VS range, not that they sounded like a valve amp to me ! My last gigging amp that I sold a couple of years ago was a monster V-S Bassamp 115 combo that really did give me a hernia Extremely loud for tranny combo, the guts being just a standard HH 100W chassis. It was probably due to the 15" speaker and enclosure design. I bought a Bass Machine which was a kick*ss 250W Mosfet job, to replace the aforementioned combo but it went wrong on it's first gig and I retired before I got round to repairing it !

6th Jun 2016, 6:31 am	#114
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,657	Re: HH TPA series Power Amplifiers. Kamran, I have the S500-D and can take a few pics for you, give me a few days though. Not sure if I can do track side of PCB, that means taking the amp apart. Got a schematic for the power amp somewhere,but the not for the pre, which is a plug in. TT/David probably does'nt have one. Do you have an S500-D or are you busy making HH clones out there in India? : ) The V series are worth looking at, all the way up to the V900. Big, very, very heavy amps. Andy. __________________ Curiosity hasn't killed this cat...so far.

7th Jun 2016, 10:10 am	#115
kamran yousaf Triode Join Date: Sep 2015 Location: Lahore, Punjab, Pakistan. Posts: 25	Re: HH TPA series Power Amplifiers. Sir, You are right and I am from Pakistan.

16th Jun 2016, 7:53 pm	#116
IamLars Retired Dormant Member Join Date: Jun 2016 Location: Stockholm, Sweden Posts: 1	Re: HH TPA series Power Amplifiers. Hi, I have had a TPA 50-D for some time but I have never tested it. However, the "slots" for fuses in the front panel are empty (1 x 2.5A AC , and 2 x 6.3A DC). Can anyone give me a specification of these fuses (Voltage , size/type) so that I can source them somehow. Thanks, /Lars